[Working with Transparency]

Thanks, I tried the Black and Alpha plugin, which is close to what I'm looking for.

Is there a way to do this without the color conversion? That is, I want to keep the Hue and Saturation data.

The other problem I find with this Black and Alpha plugin is that it doesn't respect the original alpha value. That is, when I tried converting a rectangle with 50% transparency and 50% brightness, I expect to get a rectangle with 0% brightness and 75% transparency, but I actually got a rectangle with 0% brightness and 50% transparency.

 

For the blending, "pin light" says "This mode causes light parts of the blend image and dark parts of the base image to show through." This is not what I want. I want something more like "This mode replaces the alpha channel of the base image with the alpha channel of the blend image." Is there a plugin for this?

 

[Working with Transparency]

There are two related things I want to do:

 

One thing is for a layer turn white into transparent and white-ish things into partially transparent.

Specifically, for every pixel in that layer with H, S, V, A (w, x, y, z), I want to replace it with a pixel with H, S, V, A (w, x, 0, (100-y)%*z)

 

Another thing is I want to be able to control one layer's transparency with another layer.

So basically the idea is I have a layer on top in greyscale, and a layer below it with an image at full opacity, and I want to change the image's alpha values to the color values of the layer on top.

 

Is there any plugin or layer blend mode that would let me do this?