Using a greyscale image as a 'filter' for an image in a layer below

[slefevre]

Hello, I have an effect that I want to try to do.

 

I have an image whose colors I like, but the shading and contrast I don't. I have a black and white version of that same image, where I've gotten the contract where I want it.

 

I don't know how to explain this in computer graphics terms, so bear with me:

 

What I would like to do is have an effect where I put the black and white image on a top layer, and have it 'filter' the image below it. What I mean is that, if a pixel is white in the top layer, it becomes transparent and the pixel below is shown. If the pixel is 50% grey, I want it to be 50% transparent. If it's black, it's opaque.

 

Is there a way I can do this in paint.net natively, or with a plugin?

[Ego Eram Reputo]

I'm not 100% this will do what you want, but give it a try

 

[Red ochre]

Double click on the top layer in the layers window and set the blend mode to 'multiply'?

[MJW]

Here's a plugin I wrote quite a while ago that might do what you want. The current version is very unpolished. I think maybe I'll make it into a finished pugin soon.

 

It's called Split Hue and Brightness. It's in the Color submenu.

 

It separates the hue from the brightness. Specifically, if you put the image in two layers, set the top layer's blend mode to Multiply, then run the plugin with Brightness selected for the lower layer, and Hue selected for the upper layer, it will produce the original image (more or less). In your case:

 

Put the black-and-white version in the lower layer.

Put the color version in the upper layer.

Set the upper layer's Blend Mode to Multiply.

Run the plugin on the upper layer, selecting the Hue option.

 

Split Hue and Brightness (beta version): SplitHueAndBrightness.zip

 

(Note: since multiplication is commutative, either the black-and-white or the color image can be the top layer, as long as the top layer's Blend Mode is Multiply.)