I know we kind of discussed this before in the context of using image maps for lights etc, but I'm having trouble with the simplest case. I have a stained glass window which is set up as a plane with an image map, and some other elements that are not transparent. There is a light behind it (a spotlight currently, although I had a point light before). I get a nicely outlined bit of illumination on the floor and even some atmospheric lighting... but it's all white.

I'm rendering in superfly. My render settings are the Optix Ultra Caustics preset (although I tried some others too without luck).

Here's the image:

For the shader I am using Cycles and have tried transparency, translucent, glass, and principledbsdf without luck. Here you can see all the options I've tried (not all of them are currently plugged in of course):

Even when I get rid of the map and just do TransparentBsdf and set the color to blue (for example), the light passing through it remains white. Am I missing something here?

Oh, also, the saturation is cranked up on the HSV node in case there was too much white in the image. The result is the same without the HSV node though.

What is your glass bsdf connected to?

the translucent and transparent bsdf's also appear to be not connected to anything.

Right, I wasn't actually using glass, translucent, transparent, and principled all at once. In the image it's just the principled that is connected but I also tried all three of the others in its place. I left them all in there to show how I had them set up in terms of colors and normals. Just imagine plugging any one of them in to the cycles surface node.

This is way easier than it seems like it would be. It's built into the Physical root node. Just check the "Colored Transparency" box.

Hmmm.

It's not the image map either, when I switch to just using blue:

That's like this:

Wait, I think I've got it. It appears to be that the glass has shadows turned off and that also somehow allows light to pass through but prevents it from getting colored (not sure why). Let me do some more tests.

I need to do some more work to balance the illumination of the window vs the light coming through, but at least that solves the underlying problem.

TransparentBsdf is good, glass and translucent let color through but too much scatter so it's basically just a big blur, which is probably as it should be. The above is mixing principledbsdf for the glass itself with transparent for the light passing through, and then I boosted the exposure in postFX.

Thanks for this. It was fun to learn. Never knew how to do it before. I gave it a try with the Physical Root, transparency at 1, and checked colored transparency. I used spotlights at 3000%, shadows on, and also emissions at 1 to brighten the windows.

Reduce the size of the spotlights to sharpen the transmitted images.

Ah, very nice. I don't really think of spotlight as having size but I guess they do. Reduced from 100% to 10% with no other changes. It's interesting that it only changes the size and not the total amount of light, unlike area lights.

That looks great, VedaDalsette, glad someone else is getting something out of this too!

ChromeStar, your reflected light is really sharp! Wow. I tried it again. This time I used only 1 spotlight instead of 3 like last time. I just used the render preset Optix High. I futzed around with how high and close and at what angle to put the light. I have no clue. The windows are set to emission 1, but, as hborre suggested, I lowered the intensity of the light. But I have emission of 1 coming off GROUND's background and ground. Doesn't seem to make a difference one way or another.

The light intensity in the 1st pic is at 200%. I couldn't get much reflected light any lower than that. The 2nd pic is at 500% and the third is at 2000%. I guess if I'd used your settings, it'd be crisper. And I made no changes to the materials in the figure. Someday, I'll want to use this technique, and now I know how!!! Well, sort of, hehe.

My spotlight is actually at 5000% but attenuation is set to inverse square. You would need a lower intensity if attenuation is set to constant (the default). It actually comes out a bit dark and I set Exposure at 2.0 in postFX (also saturation 0.01, contrast 0.005). My spot is pretty narrow (angle end 38.5 degrees) because it's only hitting one window. I might still change the spotlight size to 20% to be not quite as sharp, I don't know.

It's positioned at xTran 0, yTran 27.378, zTran -14.79. The window glass is basically at 0,0,0.

I do also have some emission on the glass.

I also decided to increase the density on the fog so I could get better light rays. That added a lot of render time.

I originally set this scene up to work in Firefly (a very long time ago). I don't know if there's a way to do it for real in Firefly, so I cheated and loaded the light with the same image as the glass, then set the glass to not cast shadows. That's why I had that setting wrong when I went to do it this way and I had forgotten all the details of what I had done. In case you're curious, it looked like this:

I feel like that was a pretty good result for 2006 me!

Thanks for that info. I think I was confusing light intensity with the actual light size. Doh! I think I might try and find a better figure to use for my next try. Love your foggy image. The fog, the shadows, the reflected light--gorgeous! And the Firefly image is impressive, too. 2006? Wow.

I found I have the Asian Court 1 figure with the Queen's Ballroom textures. I made no changes to the textures, just used the default set. I added no light, just used Ground with both ground and background ambient values white and set to 1. Then I rendered at Optix High with the 2 caustics boxes checked. Window material setup is below the image. I'm not saying this can't be made better, especially for color saturation, but it worked out of the box with a Poser Surface root node!

Reduce the size of the spotlights to sharpen the transmitted images.

In real life, the size of the light source sharpens or blurs shadows. Poser is mimicking real life in this.