unsharp gives strange result in CMYK mode

[johanwieland321]

we use the unsharp mask feature for RGB images (Tif and Jpegs), and this works ok for us.
But now we have a bunch of images in CMYK modus which we don't want to colorconvert to other colorspace.
Just scale, change density and apply an unsharp
But the result while working with the CMYK images gives bad result, image colors are blurred.
ImageMagick version is 6.6.7-5 on OSX, but als tried it on a PC with version 6.6.5-9

command without changing size or resolution is
convert CMYKCLIP.tif -unsharp 4x1+4+0.5 unsharpcmyk.tif (source image is 600dpi)

see screenshot of result: 3 stages
left is source image (CMYK of RGB)
middle is result from RGB image
right is result from CMYK source



the only way to avoid this behaviour is to change the Sigma to zero, but then no unsharp masking is done.
did not find anything in documentation about not using -unsharp in cmyk mode

[magick]

We can reproduce the problem you posted and have a patch. Look for it in ImageMagick 6.6.7-10 Beta by sometime tomorrow. Thanks.

[Yap]

Please upload the binaries ver of ImageMagick 6.6.7-10 Beta. I also have the same issue.

[magick]

ImageMagick 6.6.7-10 will be released within a week.

[Yap]

I'm getting the same problem using unsharp in v10, I'm using ISOnewspaper30v4.icc which is CMYK.

[magick]

We can reproduce the problem you posted and have a patch. Look for it in ImageMagick 6.6.8-0 Beta by sometime tomorrow. Thanks.

[Yap]

I'll wait for the binary version so I can try it out. Thanks.

[Yap]

The -unsharp don't work for me. Using ISOnewspaper30v4.icc and -sharpen gives the strange results like before.

[magick]

We can reproduce the problem you posted and have a patch. Look for it in ImageMagick 6.6.8-2 Beta by sometime tomorrow. Thanks.