How to use ImageMagick to batch desaturate images?

Question

I have an image that is black text with some gray and pale yellowish background. I basically want to keep the text as black as possible, and make the gray and yellow comparatively lighter...at the very least, turn yellow into a light gray. What's the most efficient way to do that in ImageMagick?

Answer 1

I'm not sure about the quality of ImageMagick's color transformations. Color is a complex and subjective area of research! I'd be a lot more comfident using an ICC profile that encoded the transformation you need, and applying it with lcms (which i've found is of the highest quality).

Now the problem becomes one of creating a transformation profile... i think Photoshop can save it's curves as profiles? maybe it's the other way around, and there are some profile tools that can use Photoshop curves as input...