CMYK image getting black on applying unsharp mask
Posted: 2016-11-09T16:57:09-07:00
HI,
IM version: ImageMagick 6.9.6-3 Q16 x86_64 2016-11-09
Webp version: libwebp-0.5.1
I am trying to resize and apply unsharp mask to a CMYK image. If i do this with target format JPG, i see after applying unsharp mask the image blackens. But same is not true if i convert to webp. I wanted to know if there is anything special with this image. Also same is not true for all cmyk images.
CMYK image : https://drive.google.com/open?id=0B_Gde ... VpUMF9VRnM
For JPEG:
Before resize : https://drive.google.com/open?id=0B_Gde ... HdZZFV1bW8
After resize: https://drive.google.com/open?id=0B_Gde ... S0yYjh4LUk
After unsharp mask : https://drive.google.com/open?id=0B_Gde ... 0ZnTHhNblk
For Webp :
Before resize : https://drive.google.com/open?id=0B_Gde ... ndyUzJqbTQ
After resize: https://drive.google.com/open?id=0B_Gde ... WxicUVGUUk
After unsharp mask : https://drive.google.com/open?id=0B_Gde ... lp0dHc1d1k
Steps i am following :
IM version: ImageMagick 6.9.6-3 Q16 x86_64 2016-11-09
Webp version: libwebp-0.5.1
I am trying to resize and apply unsharp mask to a CMYK image. If i do this with target format JPG, i see after applying unsharp mask the image blackens. But same is not true if i convert to webp. I wanted to know if there is anything special with this image. Also same is not true for all cmyk images.
CMYK image : https://drive.google.com/open?id=0B_Gde ... VpUMF9VRnM
For JPEG:
Before resize : https://drive.google.com/open?id=0B_Gde ... HdZZFV1bW8
After resize: https://drive.google.com/open?id=0B_Gde ... S0yYjh4LUk
After unsharp mask : https://drive.google.com/open?id=0B_Gde ... 0ZnTHhNblk
For Webp :
Before resize : https://drive.google.com/open?id=0B_Gde ... ndyUzJqbTQ
After resize: https://drive.google.com/open?id=0B_Gde ... WxicUVGUUk
After unsharp mask : https://drive.google.com/open?id=0B_Gde ... lp0dHc1d1k
Steps i am following :
Code: Select all
Image image_;
image_.read(fileName_);
image_.quality(80);
image_.filterType(TriangleFilter);
image_.magick("JPG"/"WEBP");
image_.write("BeforeResize.jpg");
image_.resize( boost::lexical_cast<string>(400+"x"+ 400 + "!");
image_.write("AfterResize.jpg");
image_.unsharpmask(0.8,0.5,1.2,0.05);
image_.write("AfterSHarpen.jpg");