Legacy ImageMagick Discussions Archive

Is there a way to make a pixel transparent based on its brightness level?

I would like to be able to make all pixels transparent that are in the bottom 50% of the brightness range. Let's call this image A, and say it is derived from a photo that is overexposed.

I would like to be able to make all pixels transparent that are in the top 50% of the brightness range. Let's call this image B, and say it is derived from a photo that is underexposed.

I would like to see what happens when I blend images A and B together. I hope to make an HDR image.

What version of IM on what platform? I'll assume v6 on Windows CMD.

justin9999 wrote:I would like to be able to make all pixels transparent that are in the bottom 50% of the brightness range.... top 50%...