https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=32484

diff --git a/MagickCore/channel.c b/MagickCore/channel.c
index c68b305680737f2aabaf19333565efc5db136989..158e23aca40f278153fe2725a62dace1c99a434d 100644 (file)
--- a/MagickCore/channel.c
+++ b/MagickCore/channel.c
@@ -733,10 +733,7 @@ MagickExport Image *SeparateImage(const Image *image,
     }
   separate_image->alpha_trait=UndefinedPixelTrait;
   (void) SetImageColorspace(separate_image,GRAYColorspace,exception);
-  if ((IsRGBColorspace(image->colorspace) != MagickFalse) ||
-      (image->colorspace == XYZColorspace) ||
-      (image->colorspace == xyYColorspace))
-    image->gamma=1.000;
+  separate_image->gamma=image->gamma;
   /*
     Separate image.
   */