diff --git a/src/ImageSharp/Processing/Processors/Dithering/OrderedDither.cs b/src/ImageSharp/Processing/Processors/Dithering/OrderedDither.cs
index b11411e32a..448eb3833b 100644
--- a/src/ImageSharp/Processing/Processors/Dithering/OrderedDither.cs
+++ b/src/ImageSharp/Processing/Processors/Dithering/OrderedDither.cs
@@ -262,7 +262,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Dithering
                 this.source = source;
                 this.bounds = bounds;
                 this.scale = processor.DitherScale;
-                this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(processor.Palette.Span.Length);
+                this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(processor.Palette.Length);
             }
 
             [MethodImpl(InliningOptions.ShortMethod)]