A simple question perhaps - I am getting my head around the nodes representing “blend modes” in a shader:

One of the most useful blend modes in Photoshop, Mari etc. is Overlay.

How do you guys recreate “Overlay” in a node graph where you only have Add, Subtract, Multiply or Divide?

https://en.wikipedia.org/wiki/Blend_modes [en.wikipedia.org]

Yep. Already been there jsmack. Sadly Overlay is not the most straight forward to reconstruct with simple math. Or more likely, my skills are not up to it.

The ‘photoshop’ blending modes are of limited use in shader building. Blend modes such as overlay only work correctly in gamma space, with 0-1 image data, whereas shading in mantra is in linear space, with possibly unbounded values. If you feel that you may still get some use from them, the w3c has code and examples for all the common blending modes in the SVG documentation.

Edit:
I'll try to see if I can find it again, later.

Hmm. I am comparing with Mari for example, where I work almost exclusively in linear space. It doesn't seem to affect Overlay there - which is super useful.

Composite VOP node
https://www.sidefx.com/docs/houdini/nodes/vop/composite.html [www.sidefx.com]

to bring this up to date: Labs Color Blend SOP.