diff --git a/src/ImageProcessor/Common/Extensions/ComparableExtensions.cs b/src/ImageProcessor/Common/Extensions/ComparableExtensions.cs
index e13890898..595c727bf 100644
--- a/src/ImageProcessor/Common/Extensions/ComparableExtensions.cs
+++ b/src/ImageProcessor/Common/Extensions/ComparableExtensions.cs
@@ -127,7 +127,7 @@ namespace ImageProcessor
         /// <returns>The <see cref="byte"/></returns>
         public static byte ToByte(this float value)
         {
-            return (byte)(value.Clamp(0, 255) + 0.5f);
+            return (byte)(value.Clamp(0, 255));
         }
 
         /// <summary>
@@ -138,7 +138,7 @@ namespace ImageProcessor
         /// <returns>The <see cref="byte"/></returns>
         public static byte ToByte(this double value)
         {
-            return (byte)(value.Clamp(0, 255) + 0.5d);
+            return (byte)(value.Clamp(0, 255));
         }
     }
 }
diff --git a/src/ImageProcessor/Common/Helpers/PixelOperations.cs b/src/ImageProcessor/Common/Helpers/PixelOperations.cs
index 9767268bf..a876b45ef 100644
--- a/src/ImageProcessor/Common/Helpers/PixelOperations.cs
+++ b/src/ImageProcessor/Common/Helpers/PixelOperations.cs
@@ -24,6 +24,18 @@ namespace ImageProcessor
         /// </summary>
         private static readonly Lazy<byte[]> SrgbBytes = new Lazy<byte[]>(GetSrgbBytes);
 
+        /// <summary>
+        /// The array of bytes representing each possible value of color component
+        /// converted from gamma to the linear color space.
+        /// </summary>
+        private static readonly Lazy<byte[]> LinearGammaBytes = new Lazy<byte[]>(GetLinearGammaBytes);
+
+        /// <summary>
+        /// The array of bytes representing each possible value of color component
+        /// converted from linear to the gamma color space.
+        /// </summary>
+        private static readonly Lazy<byte[]> GammaLinearBytes = new Lazy<byte[]>(GetGammaLinearBytes);
+
         /// <summary>
         /// Converts an pixel from an sRGB color-space to the equivalent linear color-space.
         /// </summary>
@@ -36,6 +48,7 @@ namespace ImageProcessor
         public static Bgra ToLinear(Bgra composite)
         {
             // Create only once and lazily.
+            // byte[] ramp = LinearGammaBytes.Value;
             byte[] ramp = LinearBytes.Value;
 
             return new Bgra(ramp[composite.B], ramp[composite.G], ramp[composite.R], composite.A);
@@ -53,6 +66,7 @@ namespace ImageProcessor
         public static Bgra ToSrgb(Bgra linear)
         {
             // Create only once and lazily.
+            // byte[] ramp = GammaLinearBytes.Value;
             byte[] ramp = SrgbBytes.Value;
 
             return new Bgra(ramp[linear.B], ramp[linear.G], ramp[linear.R], linear.A);
@@ -105,7 +119,7 @@ namespace ImageProcessor
         /// <returns>
         /// The <see cref="float"/>.
         /// </returns>
-        internal static float SrgbToLinear(float signal)
+        private static float SrgbToLinear(float signal)
         {
             float a = 0.055f;
 
@@ -126,7 +140,7 @@ namespace ImageProcessor
         /// <returns>
         /// The <see cref="float"/>.
         /// </returns>
-        internal static float LinearToSrgb(float signal)
+        private static float LinearToSrgb(float signal)
         {
             float a = 0.055f;
 
@@ -137,5 +151,43 @@ namespace ImageProcessor
 
             return ((float)((1 + a) * Math.Pow(signal, 1 / 2.4f))) - a;
         }
+
+        /// <summary>
+        /// Gets an array of bytes representing each possible value of color component
+        /// converted from gamma to the linear color space.
+        /// </summary>
+        /// <returns>
+        /// The <see cref="T:byte[]"/>.
+        /// </returns>
+        private static byte[] GetLinearGammaBytes()
+        {
+            byte[] ramp = new byte[256];
+            for (int x = 0; x < 256; ++x)
+            {
+                byte val = (255f * Math.Pow(x / 255f, 2.2)).ToByte();
+                ramp[x] = val;
+            }
+
+            return ramp;
+        }
+
+        /// <summary>
+        /// Gets an array of bytes representing each possible value of color component
+        /// converted from linear to the gamma color space.
+        /// </summary>
+        /// <returns>
+        /// The <see cref="T:byte[]"/>.
+        /// </returns>
+        private static byte[] GetGammaLinearBytes()
+        {
+            byte[] ramp = new byte[256];
+            for (int x = 0; x < 256; ++x)
+            {
+                byte val = (255f * Math.Pow(x / 255f, 1 / 2.2)).ToByte();
+                ramp[x] = val;
+            }
+
+            return ramp;
+        }
     }
 }
\ No newline at end of file
diff --git a/src/ImageProcessor/ImageProcessor.csproj b/src/ImageProcessor/ImageProcessor.csproj
index 694ea1f8f..77ea223ad 100644
--- a/src/ImageProcessor/ImageProcessor.csproj
+++ b/src/ImageProcessor/ImageProcessor.csproj
@@ -77,6 +77,7 @@
     <Compile Include="Formats\Png\Zlib\StreamManipulator.cs" />
     <Compile Include="Formats\Png\Zlib\ZipConstants.cs" />
     <Compile Include="ImageExtensions.cs" />
+    <Compile Include="Numerics\Rectangle.cs" />
     <Compile Include="ParallelImageProcessor.cs" />
     <Compile Include="IImageProcessor.cs" />
     <Compile Include="Colors\Hsv.cs" />
@@ -210,7 +211,6 @@
     <Compile Include="ImageBase.cs" />
     <Compile Include="Numerics\Point.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="Numerics\Rectangle.cs" />
     <Compile Include="Numerics\Size.cs" />
     <Compile Include="Samplers\Resamplers\Lanczos5Resampler.cs" />
     <Compile Include="Samplers\Resamplers\Lanczos8Resampler.cs" />
diff --git a/tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs b/tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs
index a109d02a7..f364dd3f0 100644
--- a/tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs
+++ b/tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs
@@ -15,12 +15,12 @@ namespace ImageProcessor.Tests
             //{ "Contrast-50", new Contrast(50) },
             //{ "Contrast--50", new Contrast(-50) },
             //{ "Alpha--50", new Alpha(50) },
-            { "Invert", new Invert() },
+            //{ "Invert", new Invert() },
             //{ "Sepia", new Sepia() },
             //{ "BlackWhite", new BlackWhite() },
             //{ "Lomograph", new Lomograph() },
             //{ "Polaroid", new Polaroid() },
-            //{ "GreyscaleBt709", new GreyscaleBt709() },
+            { "GreyscaleBt709", new GreyscaleBt709() },
             //{ "GreyscaleBt601", new GreyscaleBt601() },
         };
 
diff --git a/tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs b/tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs
index 01c38bd43..34c8656cd 100644
--- a/tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs
+++ b/tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs
@@ -19,14 +19,15 @@ namespace ImageProcessor.Tests
         /// </summary>
         public static readonly List<string> Files = new List<string>
         {
-            "../../TestImages/Formats/Jpg/Backdrop.jpg",
-            "../../TestImages/Formats/Jpg/Calliphora.jpg",
-            "../../TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg",
-            "../../TestImages/Formats/Bmp/Car.bmp",
-            "../../TestImages/Formats/Png/cmyk.png",
-            "../../TestImages/Formats/Png/gamma-1.0-or-2.2.png",
-            "../../TestImages/Formats/Gif/leaf.gif",
-            "../../TestImages/Formats/Gif/rings.gif"
+            //"../../TestImages/Formats/Jpg/Backdrop.jpg",
+            //"../../TestImages/Formats/Jpg/Calliphora.jpg",
+            //"../../TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg",
+            "../../TestImages/Formats/Jpg/greyscale.jpg",
+            //"../../TestImages/Formats/Bmp/Car.bmp",
+            //"../../TestImages/Formats/Png/cmyk.png",
+            //"../../TestImages/Formats/Png/gamma-1.0-or-2.2.png",
+            //"../../TestImages/Formats/Gif/leaf.gif",
+            //"../../TestImages/Formats/Gif/rings.gif"
 
             // { "../../TestImages/Formats/Gif/ani.gif" },
             // { "../../TestImages/Formats/Gif/ani2.gif" },
diff --git a/tests/ImageProcessor.Tests/Processors/Samplers/SamplerTests.cs b/tests/ImageProcessor.Tests/Processors/Samplers/SamplerTests.cs
index c35ff951e..49ad6576b 100644
--- a/tests/ImageProcessor.Tests/Processors/Samplers/SamplerTests.cs
+++ b/tests/ImageProcessor.Tests/Processors/Samplers/SamplerTests.cs
@@ -47,7 +47,7 @@ namespace ImageProcessor.Tests
                     using (FileStream output = File.OpenWrite($"Resized/{filename}"))
                     {
                         //image.Resize(image.Width / 2, image.Height / 2, sampler).Save(output);
-                        image.Resize(500, 500, sampler, new Rectangle(0, 0, 100, 100), new Rectangle(0, 0, 500, 500)).Save(output);
+                        image.Resize(500, 750, sampler).Save(output);
                     }
 
                     Trace.WriteLine($"{name}: {watch.ElapsedMilliseconds}ms");
diff --git a/tests/ImageProcessor.Tests/TestImages/Formats/Jpg/greyscale.jpg.REMOVED.git-id b/tests/ImageProcessor.Tests/TestImages/Formats/Jpg/greyscale.jpg.REMOVED.git-id
new file mode 100644
index 000000000..bd909a4b1
--- /dev/null
+++ b/tests/ImageProcessor.Tests/TestImages/Formats/Jpg/greyscale.jpg.REMOVED.git-id
@@ -0,0 +1 @@
+aca934c81771312563d8db52eedd95bb01164048
\ No newline at end of file