Hi folks;

I use the Poser/Semideu ZDepth render a lot to simulate depth of field and atmospheric depth, and I wonder if anyone knows if it can be used to simulate light falloff?  I have a scene which is a bit flat, being lit with infinite lights; I don't want to mess with them and risk screwing it up, but I want the light to gradually fall off towards the rear of the scene and am thinking of doing it in Photoshop with the ZDepth render, but can't work out how to do it.

Any ideas?

Am I right in thinking the various image adjustment options in Photoshop will ignore selection mask... i.e. these options apply to the whole image, or layer?

If that's right, and it is only filters that can be applied to a selection mask, then I guess you'd have to use your z-depth derived selection mask(s) to make cut-outs of each depth level you want, and split these across a number of layers... I think that's the approach I'd go with and work something out from there?

e.g. maybe you could create a cut out of your background depth level(s) and create an overlay layer with that cut-out... i.e. have the cut-out on an overlay layer set to "Darken" mode perhaps... if you see what I'm getting at?

You'd likely want to fade the edges of your "Darken" mode overlays... especially if elements in your scene receded into the background more continuously, and you didn't want a sort of parallax effect.

Hopefully my description of what I mean makes some sense?

Not tried this technique... but it's my best immediate suggestion ;)

Thanks for the tip - when Poser finishes hogging my CPU I'll give it a go. Might try adding black fog as well and see if that works!

Well, it's an intriguing idea, and I'm having great success doing the exact opposite of you want (in other words, making an area with strongly contrasting light appear to be more even and diffuse). But I also don't have a test image anything like what you describe.

The only light falloff in Poser can only be accomplished with Inverse Square on the spot and point light sets.  That approach may be feasible for just Poser alone without major post render work.

Monkeycloud - any image adjustment in Photoshop can be applied to a selection, it's not limited to filters.

So for Paul's needs here I'd paste the zdepth mask into a new Channel, then load selection, refine mask if needed, and work on a copy of the layer (toggle visibility on & off to see if the chages are working). Then just a case of experimenting with levels, curves, brightness etc.

Also easy to add painted elements like smoke etc this way too.

Great image btw Paul!

Very nice, very Fallout (which I'm playing at the moment. Alas, very evil again... sigh).