Separation command for Surface and Shading

[Peter Werner]

I would love to see something like what Tandent Lightbrush supposedly does (see this article) implemented inside of Affinity Photo. 

 

It is basically like frequency separation, except that it separates illumination and surface detail instead. It could be implemented in conjunction with a blend mode that would re-combine these two passes, just like Linear Light re-combines the high-pass layer with the low-pass one for frequency separation. 

 

I don't know if the algorithm is described in a Siggraph paper or something like that, but I believe there have been several published approaches to estimating illumination and so on.

 

I was fully expecting for something to show up in Photoshop soon after because it would be spectacularly useful for photo editing, but so far Adobe hasn't done anything in that direction yet.

 

I'm not even sure if the original product is still around.

[Peter Werner]

Update: There is now an experimental Unity plugin that seems to achieve a very similar thing, and it has been released as open source. It can even generate an environment map of the scene lighting in the process. Unfortunately this apparently requires a normal map, a bent normals map and an ambient occlusion pass in order to work. I'm not sure if these could be approximated reasonably well for a still image, but since Lightbrush, as mentioned in my post above, seems to be more than up to the task, it would suggest that a sufficiently good approximation is possible.

 

Again, I think this would be a tremendously useful feature for photo editing.