diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/CurveCalculator.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/CurveCalculator.cs
index c39eaf958..476b8188f 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/CurveCalculator.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/CurveCalculator.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.ColorProfiles.Icc.Calculators;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
@@ -9,7 +8,7 @@ namespace SixLabors.ImageSharp.ColorProfiles.Conversion.Icc;
 
 internal partial class CurveCalculator : ISingleCalculator
 {
-    private readonly LutCalculator lutCalculator;
+    private readonly LutCalculator? lutCalculator;
     private readonly float gamma;
     private readonly CalculationType type;
 
@@ -41,7 +40,7 @@ internal partial class CurveCalculator : ISingleCalculator
         {
             CalculationType.Identity => value,
             CalculationType.Gamma => MathF.Pow(value, this.gamma), // TODO: This could be optimized using a LUT. See SrgbCompanding
-            CalculationType.Lut => this.lutCalculator.Calculate(value),
+            CalculationType.Lut => this.lutCalculator!.Calculate(value),
             _ => throw new InvalidOperationException("Invalid calculation type"),
         };
 }
diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/GrayTrcCalculator.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/GrayTrcCalculator.cs
index 8d823c1e9..dffbd8055 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/GrayTrcCalculator.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/GrayTrcCalculator.cs
@@ -11,8 +11,8 @@ internal class GrayTrcCalculator : IVector4Calculator
 {
     private readonly TrcCalculator calculator;
 
-    public GrayTrcCalculator(IccTagDataEntry grayTrc, bool toPcs)
-        => this.calculator = new TrcCalculator(new IccTagDataEntry[] { grayTrc }, !toPcs);
+    public GrayTrcCalculator(IccTagDataEntry? grayTrc, bool toPcs)
+        => this.calculator = new TrcCalculator([grayTrc], !toPcs);
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public Vector4 Calculate(Vector4 value) => this.calculator.Calculate(value);
diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.CalculationType.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.CalculationType.cs
index 253239cb7..2e6338de6 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.CalculationType.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.CalculationType.cs
@@ -5,6 +5,7 @@ namespace SixLabors.ImageSharp.ColorProfiles.Conversion.Icc;
 
 internal partial class LutABCalculator
 {
+    [Flags]
     private enum CalculationType
     {
         AtoB = 1 << 3,
diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.cs
index 172d80639..7ac21309d 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutABCalculator.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Numerics;
 using SixLabors.ImageSharp.ColorProfiles.Icc.Calculators;
@@ -11,22 +10,22 @@ namespace SixLabors.ImageSharp.ColorProfiles.Conversion.Icc;
 internal partial class LutABCalculator : IVector4Calculator
 {
     private CalculationType type;
-    private TrcCalculator curveACalculator;
-    private TrcCalculator curveBCalculator;
-    private TrcCalculator curveMCalculator;
-    private MatrixCalculator matrixCalculator;
-    private ClutCalculator clutCalculator;
+    private TrcCalculator? curveACalculator;
+    private TrcCalculator? curveBCalculator;
+    private TrcCalculator? curveMCalculator;
+    private MatrixCalculator? matrixCalculator;
+    private ClutCalculator? clutCalculator;
 
     public LutABCalculator(IccLutAToBTagDataEntry entry)
     {
-        Guard.NotNull(entry, nameof(entry));
+        Guard.NotNull(entry);
         this.Init(entry.CurveA, entry.CurveB, entry.CurveM, entry.Matrix3x1, entry.Matrix3x3, entry.ClutValues);
         this.type |= CalculationType.AtoB;
     }
 
     public LutABCalculator(IccLutBToATagDataEntry entry)
     {
-        Guard.NotNull(entry, nameof(entry));
+        Guard.NotNull(entry);
         this.Init(entry.CurveA, entry.CurveB, entry.CurveM, entry.Matrix3x1, entry.Matrix3x3, entry.ClutValues);
         this.type |= CalculationType.BtoA;
     }
@@ -36,49 +35,49 @@ internal partial class LutABCalculator : IVector4Calculator
         switch (this.type)
         {
             case CalculationType.Full | CalculationType.AtoB:
-                value = this.curveACalculator.Calculate(value);
-                value = this.clutCalculator.Calculate(value);
-                value = this.curveMCalculator.Calculate(value);
-                value = this.matrixCalculator.Calculate(value);
-                return this.curveBCalculator.Calculate(value);
+                value = this.curveACalculator!.Calculate(value);
+                value = this.clutCalculator!.Calculate(value);
+                value = this.curveMCalculator!.Calculate(value);
+                value = this.matrixCalculator!.Calculate(value);
+                return this.curveBCalculator!.Calculate(value);
 
             case CalculationType.Full | CalculationType.BtoA:
-                value = this.curveBCalculator.Calculate(value);
-                value = this.matrixCalculator.Calculate(value);
-                value = this.curveMCalculator.Calculate(value);
-                value = this.clutCalculator.Calculate(value);
-                return this.curveACalculator.Calculate(value);
+                value = this.curveBCalculator!.Calculate(value);
+                value = this.matrixCalculator!.Calculate(value);
+                value = this.curveMCalculator!.Calculate(value);
+                value = this.clutCalculator!.Calculate(value);
+                return this.curveACalculator!.Calculate(value);
 
             case CalculationType.CurveClut | CalculationType.AtoB:
-                value = this.curveACalculator.Calculate(value);
-                value = this.clutCalculator.Calculate(value);
-                return this.curveBCalculator.Calculate(value);
+                value = this.curveACalculator!.Calculate(value);
+                value = this.clutCalculator!.Calculate(value);
+                return this.curveBCalculator!.Calculate(value);
 
             case CalculationType.CurveClut | CalculationType.BtoA:
-                value = this.curveBCalculator.Calculate(value);
-                value = this.clutCalculator.Calculate(value);
-                return this.curveACalculator.Calculate(value);
+                value = this.curveBCalculator!.Calculate(value);
+                value = this.clutCalculator!.Calculate(value);
+                return this.curveACalculator!.Calculate(value);
 
             case CalculationType.CurveMatrix | CalculationType.AtoB:
-                value = this.curveMCalculator.Calculate(value);
-                value = this.matrixCalculator.Calculate(value);
-                return this.curveBCalculator.Calculate(value);
+                value = this.curveMCalculator!.Calculate(value);
+                value = this.matrixCalculator!.Calculate(value);
+                return this.curveBCalculator!.Calculate(value);
 
             case CalculationType.CurveMatrix | CalculationType.BtoA:
-                value = this.curveBCalculator.Calculate(value);
-                value = this.matrixCalculator.Calculate(value);
-                return this.curveMCalculator.Calculate(value);
+                value = this.curveBCalculator!.Calculate(value);
+                value = this.matrixCalculator!.Calculate(value);
+                return this.curveMCalculator!.Calculate(value);
 
             case CalculationType.SingleCurve | CalculationType.AtoB:
             case CalculationType.SingleCurve | CalculationType.BtoA:
-                return this.curveBCalculator.Calculate(value);
+                return this.curveBCalculator!.Calculate(value);
 
             default:
                 throw new InvalidOperationException("Invalid calculation type");
         }
     }
 
-    private void Init(IccTagDataEntry[] curveA, IccTagDataEntry[] curveB, IccTagDataEntry[] curveM, Vector3? matrix3x1, Matrix4x4? matrix3x3, IccClut clut)
+    private void Init(IccTagDataEntry[]? curveA, IccTagDataEntry[]? curveB, IccTagDataEntry[]? curveM, Vector3? matrix3x1, Matrix4x4? matrix3x3, IccClut? clut)
     {
         bool hasACurve = curveA != null;
         bool hasBCurve = curveB != null;
@@ -109,27 +108,27 @@ internal partial class LutABCalculator : IVector4Calculator
 
         if (hasACurve)
         {
-            this.curveACalculator = new TrcCalculator(curveA, false);
+            this.curveACalculator = new TrcCalculator(curveA!, false);
         }
 
         if (hasBCurve)
         {
-            this.curveBCalculator = new TrcCalculator(curveB, false);
+            this.curveBCalculator = new TrcCalculator(curveB!, false);
         }
 
         if (hasMCurve)
         {
-            this.curveMCalculator = new TrcCalculator(curveM, false);
+            this.curveMCalculator = new TrcCalculator(curveM!, false);
         }
 
         if (hasMatrix)
         {
-            this.matrixCalculator = new MatrixCalculator(matrix3x3.Value, matrix3x1.Value);
+            this.matrixCalculator = new MatrixCalculator(matrix3x3!.Value, matrix3x1!.Value);
         }
 
         if (hasClut)
         {
-            this.clutCalculator = new ClutCalculator(clut);
+            this.clutCalculator = new ClutCalculator(clut!);
         }
     }
 }
diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutEntryCalculator.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutEntryCalculator.cs
index c97578ee3..5cd934d2d 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/LutEntryCalculator.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/LutEntryCalculator.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
@@ -57,6 +57,7 @@ internal class LutEntryCalculator : IVector4Calculator
         return value;
     }
 
+    [MemberNotNull(nameof(this.inputCurve), nameof(this.outputCurve), nameof(this.clutCalculator), nameof(this.matrix))]
     private void Init(IccLut[] inputCurve, IccLut[] outputCurve, IccClut clut, Matrix4x4 matrix)
     {
         this.inputCurve = InitLut(inputCurve);
diff --git a/src/ImageSharp/ColorProfiles/Icc/Calculators/TrcCalculator.cs b/src/ImageSharp/ColorProfiles/Icc/Calculators/TrcCalculator.cs
index d2fc5d9b5..3eb8d2e00 100644
--- a/src/ImageSharp/ColorProfiles/Icc/Calculators/TrcCalculator.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/Calculators/TrcCalculator.cs
@@ -12,7 +12,7 @@ internal class TrcCalculator : IVector4Calculator
 {
     private readonly ISingleCalculator[] calculators;
 
-    public TrcCalculator(IccTagDataEntry[] entries, bool inverted)
+    public TrcCalculator(IccTagDataEntry?[] entries, bool inverted)
     {
         Guard.NotNull(entries, nameof(entries));
 
diff --git a/src/ImageSharp/ColorProfiles/Icc/IccConverterBase.Checks.cs b/src/ImageSharp/ColorProfiles/Icc/IccConverterBase.Checks.cs
index 94f906709..7495f9ace 100644
--- a/src/ImageSharp/ColorProfiles/Icc/IccConverterBase.Checks.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/IccConverterBase.Checks.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 
@@ -146,10 +145,10 @@ internal abstract partial class IccConverterBase
     private static bool HasTag(IccProfile profile, IccProfileTag tag)
         => profile.Entries.Any(t => t.TagSignature == tag);
 
-    private static IccTagDataEntry GetTag(IccProfile profile, IccProfileTag tag)
+    private static IccTagDataEntry? GetTag(IccProfile profile, IccProfileTag tag)
         => Array.Find(profile.Entries, t => t.TagSignature == tag);
 
-    private static T GetTag<T>(IccProfile profile, IccProfileTag tag)
+    private static T? GetTag<T>(IccProfile profile, IccProfileTag tag)
         where T : IccTagDataEntry
         => profile.Entries.OfType<T>().FirstOrDefault(t => t.TagSignature == tag);
 }
diff --git a/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.Conversions.cs b/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.Conversions.cs
index 20df08e37..a25b15152 100644
--- a/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.Conversions.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.Conversions.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.ColorProfiles.Icc.Calculators;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 
@@ -24,6 +25,7 @@ internal abstract partial class IccConverterBase
     /// <param name="toPcs">True if the conversion is to the Profile Connection Space.</param>
     /// <param name="renderingIntent">The wanted rendering intent. Can be ignored if not available.</param>
     /// <exception cref="InvalidIccProfileException">Invalid conversion method.</exception>
+    [MemberNotNull(nameof(this.calculator))]
     protected void Init(IccProfile profile, bool toPcs, IccRenderingIntent renderingIntent)
         => this.calculator = GetConversionMethod(profile, renderingIntent) switch
         {
@@ -73,13 +75,13 @@ internal abstract partial class IccConverterBase
 
     private static ColorTrcCalculator InitColorTrc(IccProfile profile, bool toPcs)
     {
-        IccXyzTagDataEntry redMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.RedMatrixColumn);
-        IccXyzTagDataEntry greenMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.GreenMatrixColumn);
-        IccXyzTagDataEntry blueMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.BlueMatrixColumn);
+        IccXyzTagDataEntry? redMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.RedMatrixColumn);
+        IccXyzTagDataEntry? greenMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.GreenMatrixColumn);
+        IccXyzTagDataEntry? blueMatrixColumn = GetTag<IccXyzTagDataEntry>(profile, IccProfileTag.BlueMatrixColumn);
 
-        IccTagDataEntry redTrc = GetTag(profile, IccProfileTag.RedTrc);
-        IccTagDataEntry greenTrc = GetTag(profile, IccProfileTag.GreenTrc);
-        IccTagDataEntry blueTrc = GetTag(profile, IccProfileTag.BlueTrc);
+        IccTagDataEntry? redTrc = GetTag(profile, IccProfileTag.RedTrc);
+        IccTagDataEntry? greenTrc = GetTag(profile, IccProfileTag.GreenTrc);
+        IccTagDataEntry? blueTrc = GetTag(profile, IccProfileTag.BlueTrc);
 
         if (redMatrixColumn == null ||
             greenMatrixColumn == null ||
@@ -103,7 +105,7 @@ internal abstract partial class IccConverterBase
 
     private static GrayTrcCalculator InitGrayTrc(IccProfile profile, bool toPcs)
     {
-        IccTagDataEntry entry = GetTag(profile, IccProfileTag.GrayTrc);
+        IccTagDataEntry? entry = GetTag(profile, IccProfileTag.GrayTrc);
         return new GrayTrcCalculator(entry, toPcs);
     }
 }
diff --git a/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.cs b/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.cs
index d9976dc2a..70562a309 100644
--- a/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.cs
+++ b/src/ImageSharp/ColorProfiles/Icc/IccConverterbase.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Numerics;
 using System.Runtime.CompilerServices;
@@ -18,7 +17,7 @@ internal abstract partial class IccConverterBase
     /// </summary>
     /// <param name="profile">The ICC profile to use for the conversions</param>
     /// <param name="toPcs">True if the conversion is to the profile connection space (PCS); False if the conversion is to the data space</param>
-    protected IccConverterBase(IccProfile profile, bool toPcs)
+    protected IccConverterBase(IccProfile? profile, bool toPcs)
     {
         Guard.NotNull(profile, nameof(profile));
         this.Init(profile, toPcs, profile.Header.RenderingIntent);
diff --git a/src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs b/src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs
index ebf407f9b..51e984c64 100644
--- a/src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs
+++ b/src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.Common.Helpers;
 using SixLabors.ImageSharp.Metadata;
@@ -31,12 +30,14 @@ internal static class TiffDecoderMetadataCreator
                 // ICC profile data has already been resolved in the frame metadata,
                 // as it is required for color conversion.
                 ImageFrameMetadata frameMetaData = frames[i];
-                if (TryGetIptc(frameMetaData.ExifProfile.Values, out byte[] iptcBytes))
+                DebugGuard.NotNull(frameMetaData.ExifProfile);
+
+                if (TryGetIptc(frameMetaData.ExifProfile.Values, out byte[]? iptcBytes))
                 {
                     frameMetaData.IptcProfile = new IptcProfile(iptcBytes);
                 }
 
-                if (frameMetaData.ExifProfile.TryGetValue(ExifTag.XMP, out IExifValue<byte[]> xmpProfileBytes))
+                if (frameMetaData.ExifProfile.TryGetValue(ExifTag.XMP, out IExifValue<byte[]>? xmpProfileBytes))
                 {
                     frameMetaData.XmpProfile = new XmpProfile(xmpProfileBytes.Value);
                 }
@@ -65,7 +66,7 @@ internal static class TiffDecoderMetadataCreator
         return imageMetaData;
     }
 
-    private static void SetResolution(ImageMetadata imageMetaData, ExifProfile exifProfile)
+    private static void SetResolution(ImageMetadata imageMetaData, ExifProfile? exifProfile)
     {
         imageMetaData.ResolutionUnits = exifProfile != null ? UnitConverter.ExifProfileToResolutionUnit(exifProfile) : PixelResolutionUnit.PixelsPerInch;
 
@@ -74,34 +75,34 @@ internal static class TiffDecoderMetadataCreator
             return;
         }
 
-        if (exifProfile.TryGetValue(ExifTag.XResolution, out IExifValue<Rational> horizontalResolution))
+        if (exifProfile.TryGetValue(ExifTag.XResolution, out IExifValue<Rational>? horizontalResolution))
         {
             imageMetaData.HorizontalResolution = horizontalResolution.Value.ToDouble();
         }
 
-        if (exifProfile.TryGetValue(ExifTag.YResolution, out IExifValue<Rational> verticalResolution))
+        if (exifProfile.TryGetValue(ExifTag.YResolution, out IExifValue<Rational>? verticalResolution))
         {
             imageMetaData.VerticalResolution = verticalResolution.Value.ToDouble();
         }
     }
 
-    private static bool TryGetIptc(IReadOnlyList<IExifValue> exifValues, out byte[] iptcBytes)
+    private static bool TryGetIptc(IReadOnlyList<IExifValue> exifValues, out byte[]? iptcBytes)
     {
         iptcBytes = null;
-        IExifValue iptc = exifValues.FirstOrDefault(f => f.Tag == ExifTag.IPTC);
+        IExifValue? iptc = exifValues.FirstOrDefault(f => f.Tag == ExifTag.IPTC);
 
         if (iptc != null)
         {
             if (iptc.DataType is ExifDataType.Byte or ExifDataType.Undefined)
             {
-                iptcBytes = (byte[])iptc.GetValue();
+                iptcBytes = (byte[]?)iptc.GetValue();
                 return true;
             }
 
             // Some Encoders write the data type of IPTC as long.
             if (iptc.DataType == ExifDataType.Long)
             {
-                uint[] iptcValues = (uint[])iptc.GetValue();
+                uint[] iptcValues = (uint[])iptc.GetValue()!;
                 iptcBytes = new byte[iptcValues.Length * 4];
                 Buffer.BlockCopy(iptcValues, 0, iptcBytes, 0, iptcValues.Length * 4);
                 if (iptcBytes[0] == 0x1c)
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.NonPrimitives.cs b/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.NonPrimitives.cs
index 219e78559..ffe47df7c 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.NonPrimitives.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.NonPrimitives.cs
@@ -144,7 +144,7 @@ internal sealed partial class IccDataReader
                 case IccTypeSignature.MultiLocalizedUnicode:
                     return this.ReadMultiLocalizedUnicodeTagDataEntry();
                 case IccTypeSignature.TextDescription:
-                    return (IccMultiLocalizedUnicodeTagDataEntry)this.ReadTextDescriptionTagDataEntry();
+                    return ((IccMultiLocalizedUnicodeTagDataEntry)this.ReadTextDescriptionTagDataEntry())!;
 
                 default:
                     throw new InvalidIccProfileException("Profile description can only have multi-localized Unicode or text description entries");
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.TagDataEntry.cs b/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.TagDataEntry.cs
index 9e89d24ff..5c6f1e85a 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.TagDataEntry.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/DataReader/IccDataReader.TagDataEntry.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Globalization;
 using System.Numerics;
@@ -332,12 +331,12 @@ internal sealed partial class IccDataReader
         uint clutOffset = this.ReadUInt32();
         uint aCurveOffset = this.ReadUInt32();
 
-        IccTagDataEntry[] bCurve = null;
-        IccTagDataEntry[] mCurve = null;
-        IccTagDataEntry[] aCurve = null;
-        IccClut clut = null;
-        float[,] matrix3x3 = null;
-        float[] matrix3x1 = null;
+        IccTagDataEntry[]? bCurve = null;
+        IccTagDataEntry[]? mCurve = null;
+        IccTagDataEntry[]? aCurve = null;
+        IccClut? clut = null;
+        float[,]? matrix3x3 = null;
+        float[]? matrix3x1 = null;
 
         if (bCurveOffset != 0)
         {
@@ -391,12 +390,12 @@ internal sealed partial class IccDataReader
         uint clutOffset = this.ReadUInt32();
         uint aCurveOffset = this.ReadUInt32();
 
-        IccTagDataEntry[] bCurve = null;
-        IccTagDataEntry[] mCurve = null;
-        IccTagDataEntry[] aCurve = null;
-        IccClut clut = null;
-        float[,] matrix3x3 = null;
-        float[] matrix3x1 = null;
+        IccTagDataEntry[]? bCurve = null;
+        IccTagDataEntry[]? mCurve = null;
+        IccTagDataEntry[]? aCurve = null;
+        IccClut? clut = null;
+        float[,]? matrix3x3 = null;
+        float[]? matrix3x1 = null;
 
         if (bCurveOffset != 0)
         {
@@ -477,7 +476,7 @@ internal sealed partial class IccDataReader
 
         return new IccMultiLocalizedUnicodeTagDataEntry(text);
 
-        CultureInfo ReadCulture(string language, string country)
+        CultureInfo ReadCulture(string language, string? country)
         {
             if (string.IsNullOrWhiteSpace(language))
             {
@@ -775,8 +774,8 @@ internal sealed partial class IccDataReader
     /// <returns>The read entry.</returns>
     public IccTextDescriptionTagDataEntry ReadTextDescriptionTagDataEntry()
     {
-        string unicodeValue, scriptcodeValue;
-        string asciiValue = unicodeValue = scriptcodeValue = null;
+        string? unicodeValue, scriptcodeValue;
+        string? asciiValue = unicodeValue = scriptcodeValue = null;
 
         int asciiCount = (int)this.ReadUInt32();
         if (asciiCount > 0)
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.Primitives.cs b/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.Primitives.cs
index e1eebb749..a668c6120 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.Primitives.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.Primitives.cs
@@ -189,7 +189,7 @@ internal sealed partial class IccDataWriter
     /// <param name="length">The desired length of the string (including potential null terminator)</param>
     /// <param name="ensureNullTerminator">If True, there will be a \0 added at the end</param>
     /// <returns>the number of bytes written</returns>
-    public int WriteAsciiString(string value, int length, bool ensureNullTerminator)
+    public int WriteAsciiString(string? value, int length, bool ensureNullTerminator)
     {
         if (length == 0)
         {
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.TagDataEntry.cs b/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.TagDataEntry.cs
index 6019a0bff..15e53a2b4 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.TagDataEntry.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/DataWriter/IccDataWriter.TagDataEntry.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Metadata.Profiles.Icc;
 
@@ -71,7 +70,7 @@ internal sealed partial class IccDataWriter
             IccTypeSignature.UcrBg => this.WriteUcrBgTagDataEntry((IccUcrBgTagDataEntry)entry),
 
             // Unsupported or unknown
-            _ => this.WriteUnknownTagDataEntry(entry as IccUnknownTagDataEntry),
+            _ => this.WriteUnknownTagDataEntry((entry as IccUnknownTagDataEntry)!),
         };
         return count;
     }
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/IccProfile.cs b/src/ImageSharp/Metadata/Profiles/ICC/IccProfile.cs
index 05be3eb5d..b93d5e9fa 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/IccProfile.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/IccProfile.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Security.Cryptography;
 
 namespace SixLabors.ImageSharp.Metadata.Profiles.Icc;
@@ -14,23 +14,23 @@ public sealed partial class IccProfile : IDeepCloneable<IccProfile>
     /// <summary>
     /// The byte array to read the ICC profile from
     /// </summary>
-    private readonly byte[] data;
+    private readonly byte[]? data;
 
     /// <summary>
     /// The backing file for the <see cref="Entries"/> property
     /// </summary>
-    private IccTagDataEntry[] entries;
+    private IccTagDataEntry[]? entries;
 
     /// <summary>
     /// ICC profile header
     /// </summary>
-    private IccProfileHeader header;
+    private IccProfileHeader? header;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="IccProfile"/> class.
     /// </summary>
     public IccProfile()
-        : this((byte[])null)
+        : this((byte[]?)null)
     {
     }
 
@@ -38,7 +38,7 @@ public sealed partial class IccProfile : IDeepCloneable<IccProfile>
     /// Initializes a new instance of the <see cref="IccProfile"/> class.
     /// </summary>
     /// <param name="data">The raw ICC profile data</param>
-    public IccProfile(byte[] data) => this.data = data;
+    public IccProfile(byte[]? data) => this.data = data;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="IccProfile"/> class.
@@ -177,6 +177,7 @@ public sealed partial class IccProfile : IDeepCloneable<IccProfile>
         return IccWriter.Write(this);
     }
 
+    [MemberNotNull(nameof(this.header))]
     private void InitializeHeader()
     {
         if (this.header != null)
@@ -193,6 +194,7 @@ public sealed partial class IccProfile : IDeepCloneable<IccProfile>
         this.header = IccReader.ReadHeader(this.data);
     }
 
+    [MemberNotNull(nameof(this.entries))]
     private void InitializeEntries()
     {
         if (this.entries != null)
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/IccProfileHeader.cs b/src/ImageSharp/Metadata/Profiles/ICC/IccProfileHeader.cs
index 959668aaf..cea2a6cc2 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/IccProfileHeader.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/IccProfileHeader.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Numerics;
 
@@ -19,7 +18,7 @@ public sealed class IccProfileHeader
     /// <summary>
     /// Gets or sets the preferred CMM (Color Management Module) type.
     /// </summary>
-    public string CmmType { get; set; }
+    public string? CmmType { get; set; }
 
     /// <summary>
     /// Gets or sets the profiles version number.
@@ -50,7 +49,7 @@ public sealed class IccProfileHeader
     /// Gets or sets the file signature. Should always be "acsp".
     /// Value will be ignored when writing a profile.
     /// </summary>
-    public string FileSignature { get; set; }
+    public string? FileSignature { get; set; }
 
     /// <summary>
     /// Gets or sets the primary platform this profile as created for
@@ -91,7 +90,7 @@ public sealed class IccProfileHeader
     /// <summary>
     /// Gets or sets profile creator signature.
     /// </summary>
-    public string CreatorSignature { get; set; }
+    public string? CreatorSignature { get; set; }
 
     /// <summary>
     /// Gets or sets the profile ID (hash).
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutAToBTagDataEntry.cs b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutAToBTagDataEntry.cs
index 9bf323263..9d404ddb1 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutAToBTagDataEntry.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutAToBTagDataEntry.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 
 // TODO: Review the use of base IccTagDataEntry comparison.
@@ -22,12 +22,12 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
     /// <param name="clutValues">CLUT</param>
     /// <param name="curveA">A Curve</param>
     public IccLutAToBTagDataEntry(
-        IccTagDataEntry[] curveB,
-        float[,] matrix3x3,
-        float[] matrix3x1,
-        IccTagDataEntry[] curveM,
-        IccClut clutValues,
-        IccTagDataEntry[] curveA)
+        IccTagDataEntry[]? curveB,
+        float[,]? matrix3x3,
+        float[]? matrix3x1,
+        IccTagDataEntry[]? curveM,
+        IccClut? clutValues,
+        IccTagDataEntry[]? curveA)
         : this(curveB, matrix3x3, matrix3x1, curveM, clutValues, curveA, IccProfileTag.Unknown)
     {
     }
@@ -43,12 +43,12 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
     /// <param name="curveA">A Curve</param>
     /// <param name="tagSignature">Tag Signature</param>
     public IccLutAToBTagDataEntry(
-        IccTagDataEntry[] curveB,
-        float[,] matrix3x3,
-        float[] matrix3x1,
-        IccTagDataEntry[] curveM,
-        IccClut clutValues,
-        IccTagDataEntry[] curveA,
+        IccTagDataEntry[]? curveB,
+        float[,]? matrix3x3,
+        float[]? matrix3x1,
+        IccTagDataEntry[]? curveM,
+        IccClut? clutValues,
+        IccTagDataEntry[]? curveA,
         IccProfileTag tagSignature)
     : base(IccTypeSignature.LutAToB, tagSignature)
     {
@@ -70,11 +70,11 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
             Guard.IsTrue(this.CurveM.Length == 3, nameof(this.CurveM), $"{nameof(this.CurveM)} must have a length of three");
             Guard.MustBeBetweenOrEqualTo(this.CurveA.Length, 1, 15, nameof(this.CurveA));
 
-            this.InputChannelCount = curveA.Length;
+            this.InputChannelCount = this.CurveA.Length;
             this.OutputChannelCount = 3;
 
-            Guard.IsTrue(this.InputChannelCount == clutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
-            Guard.IsTrue(this.OutputChannelCount == clutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
+            Guard.IsTrue(this.InputChannelCount == this.ClutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
+            Guard.IsTrue(this.OutputChannelCount == this.ClutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
         }
         else if (this.IsMMatrixB())
         {
@@ -88,11 +88,11 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
             Guard.MustBeBetweenOrEqualTo(this.CurveA.Length, 1, 15, nameof(this.CurveA));
             Guard.MustBeBetweenOrEqualTo(this.CurveB.Length, 1, 15, nameof(this.CurveB));
 
-            this.InputChannelCount = curveA.Length;
-            this.OutputChannelCount = curveB.Length;
+            this.InputChannelCount = this.CurveA.Length;
+            this.OutputChannelCount = this.CurveB.Length;
 
-            Guard.IsTrue(this.InputChannelCount == clutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
-            Guard.IsTrue(this.OutputChannelCount == clutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
+            Guard.IsTrue(this.InputChannelCount == this.ClutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
+            Guard.IsTrue(this.OutputChannelCount == this.ClutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
         }
         else if (this.IsB())
         {
@@ -127,28 +127,28 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
     /// <summary>
     /// Gets the color lookup table
     /// </summary>
-    public IccClut ClutValues { get; }
+    public IccClut? ClutValues { get; }
 
     /// <summary>
     /// Gets the B Curve
     /// </summary>
-    public IccTagDataEntry[] CurveB { get; }
+    public IccTagDataEntry[]? CurveB { get; }
 
     /// <summary>
     /// Gets the M Curve
     /// </summary>
-    public IccTagDataEntry[] CurveM { get; }
+    public IccTagDataEntry[]? CurveM { get; }
 
     /// <summary>
     /// Gets the A Curve
     /// </summary>
-    public IccTagDataEntry[] CurveA { get; }
+    public IccTagDataEntry[]? CurveA { get; }
 
     /// <inheritdoc/>
-    public override bool Equals(IccTagDataEntry other) => other is IccLutAToBTagDataEntry entry && this.Equals(entry);
+    public override bool Equals(IccTagDataEntry? other) => other is IccLutAToBTagDataEntry entry && this.Equals(entry);
 
     /// <inheritdoc/>
-    public bool Equals(IccLutAToBTagDataEntry other)
+    public bool Equals(IccLutAToBTagDataEntry? other)
     {
         if (other is null)
         {
@@ -165,14 +165,14 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
             && this.OutputChannelCount == other.OutputChannelCount
             && this.Matrix3x3.Equals(other.Matrix3x3)
             && this.Matrix3x1.Equals(other.Matrix3x1)
-            && this.ClutValues.Equals(other.ClutValues)
+            && this.ClutValues!.Equals(other.ClutValues)
             && EqualsCurve(this.CurveB, other.CurveB)
             && EqualsCurve(this.CurveM, other.CurveM)
             && EqualsCurve(this.CurveA, other.CurveA);
     }
 
     /// <inheritdoc/>
-    public override bool Equals(object obj) => obj is IccLutAToBTagDataEntry other && this.Equals(other);
+    public override bool Equals(object? obj) => obj is IccLutAToBTagDataEntry other && this.Equals(other);
 
     /// <inheritdoc/>
     public override int GetHashCode()
@@ -192,7 +192,7 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
         return hashCode.ToHashCode();
     }
 
-    private static bool EqualsCurve(IccTagDataEntry[] thisCurves, IccTagDataEntry[] entryCurves)
+    private static bool EqualsCurve(IccTagDataEntry[]? thisCurves, IccTagDataEntry[]? entryCurves)
     {
         bool thisNull = thisCurves is null;
         bool entryNull = entryCurves is null;
@@ -207,9 +207,13 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
             return false;
         }
 
+        DebugGuard.NotNull(thisCurves);
+        DebugGuard.NotNull(entryCurves);
+
         return thisCurves.SequenceEqual(entryCurves);
     }
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(Matrix3x3), nameof(this.Matrix3x1), nameof(this.CurveM), nameof(this.ClutValues), nameof(this.CurveA))]
     private bool IsAClutMMatrixB()
         => this.CurveB != null
         && this.Matrix3x3 != null
@@ -218,20 +222,23 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
         && this.ClutValues != null
         && this.CurveA != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(Matrix3x3), nameof(this.Matrix3x1), nameof(this.CurveM))]
     private bool IsMMatrixB()
         => this.CurveB != null
         && this.Matrix3x3 != null
         && this.Matrix3x1 != null
         && this.CurveM != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(this.ClutValues), nameof(this.CurveA))]
     private bool IsAClutB()
         => this.CurveB != null
         && this.ClutValues != null
         && this.CurveA != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB))]
     private bool IsB() => this.CurveB != null;
 
-    private void VerifyCurve(IccTagDataEntry[] curves, string name)
+    private void VerifyCurve(IccTagDataEntry[]? curves, string name)
     {
         if (curves != null)
         {
@@ -240,7 +247,7 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
         }
     }
 
-    private static void VerifyMatrix(float[,] matrix3x3, float[] matrix3x1)
+    private static void VerifyMatrix(float[,]? matrix3x3, float[]? matrix3x1)
     {
         if (matrix3x1 != null)
         {
@@ -254,7 +261,7 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
         }
     }
 
-    private static Vector3? CreateMatrix3x1(float[] matrix)
+    private static Vector3? CreateMatrix3x1(float[]? matrix)
     {
         if (matrix is null)
         {
@@ -264,7 +271,7 @@ internal sealed class IccLutAToBTagDataEntry : IccTagDataEntry, IEquatable<IccLu
         return new Vector3(matrix[0], matrix[1], matrix[2]);
     }
 
-    private static Matrix4x4? CreateMatrix3x3(float[,] matrix)
+    private static Matrix4x4? CreateMatrix3x3(float[,]? matrix)
     {
         if (matrix is null)
         {
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutBToATagDataEntry.cs b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutBToATagDataEntry.cs
index 033b80989..73b884c67 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutBToATagDataEntry.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccLutBToATagDataEntry.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 
 // TODO: Review the use of base IccTagDataEntry comparison.
@@ -15,19 +15,19 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
     /// <summary>
     /// Initializes a new instance of the <see cref="IccLutBToATagDataEntry"/> class.
     /// </summary>
-    /// <param name="curveB">B Curve</param>
-    /// <param name="matrix3x3">Two dimensional conversion matrix (3x3)</param>
-    /// <param name="matrix3x1">One dimensional conversion matrix (3x1)</param>
-    /// <param name="curveM">M Curve</param>
-    /// <param name="clutValues">CLUT</param>
-    /// <param name="curveA">A Curve</param>
+    /// <param name="curveB">B Curve.</param>
+    /// <param name="matrix3x3">Two dimensional conversion matrix (3x3).</param>
+    /// <param name="matrix3x1">One dimensional conversion matrix (3x1).</param>
+    /// <param name="curveM">M Curve.</param>
+    /// <param name="clutValues">CLUT.</param>
+    /// <param name="curveA">A Curve.</param>
     public IccLutBToATagDataEntry(
-        IccTagDataEntry[] curveB,
-        float[,] matrix3x3,
-        float[] matrix3x1,
-        IccTagDataEntry[] curveM,
-        IccClut clutValues,
-        IccTagDataEntry[] curveA)
+        IccTagDataEntry[]? curveB,
+        float[,]? matrix3x3,
+        float[]? matrix3x1,
+        IccTagDataEntry[]? curveM,
+        IccClut? clutValues,
+        IccTagDataEntry[]? curveA)
         : this(curveB, matrix3x3, matrix3x1, curveM, clutValues, curveA, IccProfileTag.Unknown)
     {
     }
@@ -35,20 +35,20 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
     /// <summary>
     /// Initializes a new instance of the <see cref="IccLutBToATagDataEntry"/> class.
     /// </summary>
-    /// <param name="curveB">B Curve</param>
-    /// <param name="matrix3x3">Two dimensional conversion matrix (3x3)</param>
-    /// <param name="matrix3x1">One dimensional conversion matrix (3x1)</param>
-    /// <param name="curveM">M Curve</param>
-    /// <param name="clutValues">CLUT</param>
-    /// <param name="curveA">A Curve</param>
-    /// <param name="tagSignature">Tag Signature</param>
+    /// <param name="curveB">B Curve.</param>
+    /// <param name="matrix3x3">Two dimensional conversion matrix (3x3).</param>
+    /// <param name="matrix3x1">One dimensional conversion matrix (3x1).</param>
+    /// <param name="curveM">M Curve.</param>
+    /// <param name="clutValues">CLUT.</param>
+    /// <param name="curveA">A Curve.</param>
+    /// <param name="tagSignature">Tag Signature.</param>
     public IccLutBToATagDataEntry(
-        IccTagDataEntry[] curveB,
-        float[,] matrix3x3,
-        float[] matrix3x1,
-        IccTagDataEntry[] curveM,
-        IccClut clutValues,
-        IccTagDataEntry[] curveA,
+        IccTagDataEntry[]? curveB,
+        float[,]? matrix3x3,
+        float[]? matrix3x1,
+        IccTagDataEntry[]? curveM,
+        IccClut? clutValues,
+        IccTagDataEntry[]? curveA,
         IccProfileTag tagSignature)
         : base(IccTypeSignature.LutBToA, tagSignature)
     {
@@ -71,10 +71,10 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
             Guard.MustBeBetweenOrEqualTo(this.CurveA.Length, 1, 15, nameof(this.CurveA));
 
             this.InputChannelCount = 3;
-            this.OutputChannelCount = curveA.Length;
+            this.OutputChannelCount = this.CurveA.Length;
 
-            Guard.IsTrue(this.InputChannelCount == clutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
-            Guard.IsTrue(this.OutputChannelCount == clutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
+            Guard.IsTrue(this.InputChannelCount == this.ClutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
+            Guard.IsTrue(this.OutputChannelCount == this.ClutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
         }
         else if (this.IsBMatrixM())
         {
@@ -88,11 +88,11 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
             Guard.MustBeBetweenOrEqualTo(this.CurveA.Length, 1, 15, nameof(this.CurveA));
             Guard.MustBeBetweenOrEqualTo(this.CurveB.Length, 1, 15, nameof(this.CurveB));
 
-            this.InputChannelCount = curveB.Length;
-            this.OutputChannelCount = curveA.Length;
+            this.InputChannelCount = this.CurveB.Length;
+            this.OutputChannelCount = this.CurveA.Length;
 
-            Guard.IsTrue(this.InputChannelCount == clutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
-            Guard.IsTrue(this.OutputChannelCount == clutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
+            Guard.IsTrue(this.InputChannelCount == this.ClutValues.InputChannelCount, nameof(clutValues), "Input channel count does not match the CLUT size");
+            Guard.IsTrue(this.OutputChannelCount == this.ClutValues.OutputChannelCount, nameof(clutValues), "Output channel count does not match the CLUT size");
         }
         else if (this.IsB())
         {
@@ -105,50 +105,50 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
     }
 
     /// <summary>
-    /// Gets the number of input channels
+    /// Gets the number of input channels.
     /// </summary>
     public int InputChannelCount { get; }
 
     /// <summary>
-    /// Gets the number of output channels
+    /// Gets the number of output channels.
     /// </summary>
     public int OutputChannelCount { get; }
 
     /// <summary>
-    /// Gets the two dimensional conversion matrix (3x3)
+    /// Gets the two dimensional conversion matrix (3x3).
     /// </summary>
     public Matrix4x4? Matrix3x3 { get; }
 
     /// <summary>
-    /// Gets the one dimensional conversion matrix (3x1)
+    /// Gets the one dimensional conversion matrix (3x1).
     /// </summary>
     public Vector3? Matrix3x1 { get; }
 
     /// <summary>
-    /// Gets the color lookup table
+    /// Gets the color lookup table.
     /// </summary>
-    public IccClut ClutValues { get; }
+    public IccClut? ClutValues { get; }
 
     /// <summary>
-    /// Gets the B Curve
+    /// Gets the B Curve.
     /// </summary>
-    public IccTagDataEntry[] CurveB { get; }
+    public IccTagDataEntry[]? CurveB { get; }
 
     /// <summary>
-    /// Gets the M Curve
+    /// Gets the M Curve.
     /// </summary>
-    public IccTagDataEntry[] CurveM { get; }
+    public IccTagDataEntry[]? CurveM { get; }
 
     /// <summary>
-    /// Gets the A Curve
+    /// Gets the A Curve.
     /// </summary>
-    public IccTagDataEntry[] CurveA { get; }
+    public IccTagDataEntry[]? CurveA { get; }
 
     /// <inheritdoc/>
-    public override bool Equals(IccTagDataEntry other) => other is IccLutBToATagDataEntry entry && this.Equals(entry);
+    public override bool Equals(IccTagDataEntry? other) => other is IccLutBToATagDataEntry entry && this.Equals(entry);
 
     /// <inheritdoc/>
-    public bool Equals(IccLutBToATagDataEntry other)
+    public bool Equals(IccLutBToATagDataEntry? other)
     {
         if (other is null)
         {
@@ -165,14 +165,14 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
             && this.OutputChannelCount == other.OutputChannelCount
             && this.Matrix3x3.Equals(other.Matrix3x3)
             && this.Matrix3x1.Equals(other.Matrix3x1)
-            && this.ClutValues.Equals(other.ClutValues)
+            && this.ClutValues!.Equals(other.ClutValues)
             && EqualsCurve(this.CurveB, other.CurveB)
             && EqualsCurve(this.CurveM, other.CurveM)
             && EqualsCurve(this.CurveA, other.CurveA);
     }
 
     /// <inheritdoc/>
-    public override bool Equals(object obj) => obj is IccLutBToATagDataEntry other && this.Equals(other);
+    public override bool Equals(object? obj) => obj is IccLutBToATagDataEntry other && this.Equals(other);
 
     /// <inheritdoc/>
     public override int GetHashCode()
@@ -191,7 +191,7 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
         return hashCode.ToHashCode();
     }
 
-    private static bool EqualsCurve(IccTagDataEntry[] thisCurves, IccTagDataEntry[] entryCurves)
+    private static bool EqualsCurve(IccTagDataEntry[]? thisCurves, IccTagDataEntry[]? entryCurves)
     {
         bool thisNull = thisCurves is null;
         bool entryNull = entryCurves is null;
@@ -206,21 +206,28 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
             return false;
         }
 
+        DebugGuard.NotNull(thisCurves);
+        DebugGuard.NotNull(entryCurves);
+
         return thisCurves.SequenceEqual(entryCurves);
     }
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(Matrix3x3), nameof(Matrix3x1), nameof(CurveM), nameof(ClutValues), nameof(CurveA))]
     private bool IsBMatrixMClutA()
     => this.CurveB != null && this.Matrix3x3 != null && this.Matrix3x1 != null && this.CurveM != null && this.ClutValues != null && this.CurveA != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(this.Matrix3x3), nameof(this.Matrix3x1), nameof(this.CurveM))]
     private bool IsBMatrixM()
     => this.CurveB != null && this.Matrix3x3 != null && this.Matrix3x1 != null && this.CurveM != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB), nameof(this.ClutValues), nameof(this.CurveA))]
     private bool IsBClutA()
     => this.CurveB != null && this.ClutValues != null && this.CurveA != null;
 
+    [MemberNotNullWhen(true, nameof(this.CurveB))]
     private bool IsB() => this.CurveB != null;
 
-    private void VerifyCurve(IccTagDataEntry[] curves, string name)
+    private void VerifyCurve(IccTagDataEntry[]? curves, string name)
     {
         if (curves != null)
         {
@@ -229,7 +236,7 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
         }
     }
 
-    private static void VerifyMatrix(float[,] matrix3x3, float[] matrix3x1)
+    private static void VerifyMatrix(float[,]? matrix3x3, float[]? matrix3x1)
     {
         if (matrix3x1 != null)
         {
@@ -243,7 +250,7 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
         }
     }
 
-    private static Vector3? CreateMatrix3x1(float[] matrix)
+    private static Vector3? CreateMatrix3x1(float[]? matrix)
     {
         if (matrix is null)
         {
@@ -253,7 +260,7 @@ internal sealed class IccLutBToATagDataEntry : IccTagDataEntry, IEquatable<IccLu
         return new Vector3(matrix[0], matrix[1], matrix[2]);
     }
 
-    private static Matrix4x4? CreateMatrix3x3(float[,] matrix)
+    private static Matrix4x4? CreateMatrix3x3(float[,]? matrix)
     {
         if (matrix is null)
         {
diff --git a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccTextDescriptionTagDataEntry.cs b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccTextDescriptionTagDataEntry.cs
index 7db26e5c5..6d21fe93b 100644
--- a/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccTextDescriptionTagDataEntry.cs
+++ b/src/ImageSharp/Metadata/Profiles/ICC/TagDataEntries/IccTextDescriptionTagDataEntry.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Globalization;
 
@@ -19,7 +18,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     /// <param name="scriptCode">ScriptCode text</param>
     /// <param name="unicodeLanguageCode">Unicode Language-Code</param>
     /// <param name="scriptCodeCode">ScriptCode Code</param>
-    public IccTextDescriptionTagDataEntry(string ascii, string unicode, string scriptCode, uint unicodeLanguageCode, ushort scriptCodeCode)
+    public IccTextDescriptionTagDataEntry(string? ascii, string? unicode, string? scriptCode, uint unicodeLanguageCode, ushort scriptCodeCode)
         : this(ascii, unicode, scriptCode, unicodeLanguageCode, scriptCodeCode, IccProfileTag.Unknown)
     {
     }
@@ -33,7 +32,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     /// <param name="unicodeLanguageCode">Unicode Language-Code</param>
     /// <param name="scriptCodeCode">ScriptCode Code</param>
     /// <param name="tagSignature">Tag Signature</param>
-    public IccTextDescriptionTagDataEntry(string ascii, string unicode, string scriptCode, uint unicodeLanguageCode, ushort scriptCodeCode, IccProfileTag tagSignature)
+    public IccTextDescriptionTagDataEntry(string? ascii, string? unicode, string? scriptCode, uint unicodeLanguageCode, ushort scriptCodeCode, IccProfileTag tagSignature)
         : base(IccTypeSignature.TextDescription, tagSignature)
     {
         this.Ascii = ascii;
@@ -46,17 +45,17 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     /// <summary>
     /// Gets the ASCII text
     /// </summary>
-    public string Ascii { get; }
+    public string? Ascii { get; }
 
     /// <summary>
     /// Gets the Unicode text
     /// </summary>
-    public string Unicode { get; }
+    public string? Unicode { get; }
 
     /// <summary>
     /// Gets the ScriptCode text
     /// </summary>
-    public string ScriptCode { get; }
+    public string? ScriptCode { get; }
 
     /// <summary>
     /// Gets the Unicode Language-Code
@@ -74,7 +73,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     /// </summary>
     /// <param name="textEntry">The entry to convert</param>
     /// <returns>The converted entry</returns>
-    public static explicit operator IccMultiLocalizedUnicodeTagDataEntry(IccTextDescriptionTagDataEntry textEntry)
+    public static explicit operator IccMultiLocalizedUnicodeTagDataEntry?(IccTextDescriptionTagDataEntry? textEntry)
     {
         if (textEntry is null)
         {
@@ -84,7 +83,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
         IccLocalizedString localString;
         if (!string.IsNullOrEmpty(textEntry.Unicode))
         {
-            CultureInfo culture = GetCulture(textEntry.UnicodeLanguageCode);
+            CultureInfo? culture = GetCulture(textEntry.UnicodeLanguageCode);
             localString = culture != null
                 ? new IccLocalizedString(culture, textEntry.Unicode)
                 : new IccLocalizedString(textEntry.Unicode);
@@ -104,7 +103,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
 
         return new IccMultiLocalizedUnicodeTagDataEntry(new[] { localString }, textEntry.TagSignature);
 
-        static CultureInfo GetCulture(uint value)
+        static CultureInfo? GetCulture(uint value)
         {
             if (value == 0)
             {
@@ -131,11 +130,11 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     }
 
     /// <inheritdoc/>
-    public override bool Equals(IccTagDataEntry other)
+    public override bool Equals(IccTagDataEntry? other)
         => other is IccTextDescriptionTagDataEntry entry && this.Equals(entry);
 
     /// <inheritdoc />
-    public bool Equals(IccTextDescriptionTagDataEntry other)
+    public bool Equals(IccTextDescriptionTagDataEntry? other)
     {
         if (other is null)
         {
@@ -156,7 +155,7 @@ internal sealed class IccTextDescriptionTagDataEntry : IccTagDataEntry, IEquatab
     }
 
     /// <inheritdoc />
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is IccTextDescriptionTagDataEntry other && this.Equals(other);
 
     /// <inheritdoc />