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I want to create an image only with highlights in Blender using the following method:

Image -> increase lightness = Image 2

Image 2 -> covert to black and white = BW-Mask

apply BW-Mask to image 2 like in Gimp to get Image 3 than contains only highlights and the rest of the image is transparent.

Thanks in advance...

Paco de Lucia
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1 Answers1

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All you have to do is to multiply the image by a variable using the Converter --> Math node (This will automatically convert to BW).

Then you use the Converter --> Set alpha node while using the same image as the mask. enter image description here

Omar Emara
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  • Thanks Omar a lot for answering so fast. Your input was very helpful. My initial intention is to create a basic HDR effect on a movie by increasing the highlights. Now I have created tow versions of the input image: one with more highlights and the other with more shadows. I created masks according to your description to filter the images. Now I want to merge the pictures together using the color mix but I do not get desired result. Do you have an idea? – Paco de Lucia Nov 03 '16 at 11:31
  • Here is an overview of my workflow: https://goo.gl/EZklcA – Paco de Lucia Nov 03 '16 at 11:38
  • @PacodeLucia Contrast enhancement of HDRI image seems like an advanced topic for a simple node tree, When I have time I will explore some algorithms and implement a solution and get back to you. – Omar Emara Nov 03 '16 at 14:54