So I wrote a little spreadsheet which helps out.

Enter (in column B) what you want the output component to be, and column C gives you what you should enter in the color picker.

I thought all color swatches and maps were corrected at render except for the User Defined node?

Poser Gamma Correction performs an anti-GC on image maps and color swatches, then the rendering kicks in, and then a GC is peformed on the result.This sandwich approach makes it very different from other forms of CG, which work on the final render only (as a post-process).

As a result, the Poser GC affects the effects of lighting / shading only while plainly lit areas stay intact. Vue GC works sort of similar, but different in its details.

See http://www.book.artbeeweb.nl/?p=317 for more.

Quote - I thought all color swatches and maps were corrected at render except for the User Defined node?

It does? I didn't realize that.

It's even worse, the first anti-GC part of the sandwich does not work on all numericals.

The User Defined node takes numericals, no actual colors involved.

But also the 50% white (=grey) Diffuse color at 100% value works different from the 100% white at 50% Diffuse value, as only the color swatch is affected.

So for simplicity: Poser GC reduces the contrasts and extremes of highlights and shadows (and other shading), but not color as such.

Quote - It's even worse, the first anti-GC part of the sandwich does not work on all numericals.

The User Defined node takes numericals, no actual colors involved.

But also the 50% white (=grey) Diffuse color at 100% value works different from the 100% white at 50% Diffuse value, as only the color swatch is affected.

So for simplicity: Poser GC reduces the contrasts and extremes of highlights and shadows (and other shading), but not color as such.

So I'm confused. Say I use a brick node. Do I have to worry about anti-gamma correcting the values I use for the colors?

brick node: no worry. If you make a wall out of it, and use plain lighting, then dark red (127,0,0) will come out as dark red. When you make a shiny ball out of it, you'll notice that the shadows will not darken that much and the highlights will be softer, compared to a non-GC render.

diffuse node: watch out. Dark red (127,0,0) a 100% will behave different from bright red (255,0,0) at 50%. This is because the (50%,0,0) color is anti-GC'd but the 50% value is not.
Also channel addition (diffuse + ambient + ...) works different under GC. This turns the older Vicky textures - with the cyannic teint in diffuse - into the long smoking zombie look when GC is switched on. Knownto PoserPro users since 2010, now in theatre for P9 users as well. Welcome aboard.

Quote - brick node: no worry. If you make a wall out of it, and use plain lighting, then dark red (127,0,0) will come out as dark red. When you make a shiny ball out of it, you'll notice that the shadows will not darken that much and the highlights will be softer, compared to a non-GC render.

diffuse node: watch out. Dark red (127,0,0) a 100% will behave different from bright red (255,0,0) at 50%. This is because the (50%,0,0) color is anti-GC'd but the 50% value is not.
Also channel addition (diffuse + ambient + ...) works different under GC. This turns the older Vicky textures - with the cyannic teint in diffuse - into the long smoking zombie look when GC is switched on. Knownto PoserPro users since 2010, now in theatre for P9 users as well. Welcome aboard.

Aha. Thanks