Legacy ImageMagick Discussions Archive

Sorry if this is a simple question, but I can't find info online.

I have substracted two images and would like scale the resulting diff image by some constant to make differences more noticeable. I'd imagine ImageMagick is able to do this, but I can't find the right commands for this. Can anyone point me to the right place, documentation?

If you want to multiply all the pixel values by a certain factor, such as 45, then "-evaluate Multiply 45". See http://imagemagick.org/script/command-l ... p#evaluate

"-auto-level" may also be useful.

Thanks, it works. I just achieved the same result using -color-matrix. It seems though there is something wrong with the examples here http://www.imagemagick.org/Usage/color_ ... lor-matrix

It doesn't work if colon is placed after input file name as in the example, the convert tool just keeps reading input from console (Windows 8.1).

The usage pages show Bash commands, not Windows commands. See http://www.imagemagick.org/Usage/windows/

For example, use double-quotes for Windows: Or, I believe better, don't use spaces so you don't need quotes:

voldemarz wrote:Thanks, it works. I just achieved the same result using -color-matrix. It seems though there is something wrong with the examples here http://www.imagemagick.org/Usage/color_ ... lor-matrix

It doesn't work if colon is placed after input file name as in the example, the convert tool just keeps reading input from console (Windows 8.1).

The colon ':' in "rose:" is part of the name of a built in image. for a file you would not have a colon unless you are specifying the image type of the file. EG: "type:filename"