Is it possible to apply an image map to a spotlight in Poser 12 using Superfly? I have not had any luck getting it to work (but it did work in P11). Also tried an area light. If it's possible, can someone show or describe how they set it up?

If that's not possible, any suggestions on how to set up an image as a filter, i.e. put a colored flat plane in front of the light? How far should it be from the light, what shaders would you use for it? I have not gotten it to work very well.

I'm trying to get a projected effect, so just using emissive surfaces is not a good solution here.

Right now the only way is to use a real gobo to do it. Make a trans-mapped plane with the desired image and set it right in front of the light. It's theoretically possible to setup a cycles light to use an image map but it's really convoluted and I've never achieved useful results.

OK, thanks. Can you suggest what shaders are best for that gobo? TransparentBSDF, RefractionBSDF with ior 1.0, PhysicalSurface with colored transparency, etc? Everything I try seems to result in very little light going through. I turned the light up to 10000% at short range and am still not happy with it (although I do get some color).

I've also tried without any success in P12 Superfly.  It just can't be done.  Maybe in P13?

Which is horrible because there were some great light gobos with some sets from sadly dead RDNA I have and now can't use unless I go back to P14.

How are you driving your transparency for your prop?  Include screencap.

At the moment I just have Cycles surface --> TransparentBSDF color --> ImageMap. That seems like it should work for a gobo, and there aren't really any settings to get wrong. Positioning and scaling the gobo seems a bit iffy though. I switched to a sphere for the gobo but it seems like I am not getting much detail, everything is blurring into one color.

Add the LightPath node to the arrangement as illustrated below to intensify the light transmission through the gobo.  I tested it on a flattened box and an area light with 100% intensity was too bright for my render.  I would start at 5% and increase incrementally.

Experiment with the settings on the node.

This is as far as I got creating a gobo with a variable color cellular node.  I managed to differentiate the colors by moving the area light away from the flat box prop, so distance and light intensity are key factors.  

That made utterly no difference -- I get exactly the same image with that arrangement as I do with just TransparentBsdf alone.

And on reading up on LightPath, that's the expected result. Light passing through TransparentBsdf doesn't become a transmission ray https://docs.blender.org/manual/en/2.79/render/cycles/settings/scene/render/light_paths.html so the value is always 0 https://docs.blender.org/manual/en/latest/render/shader_nodes/input/light_path.html , and everything goes to the TransparentBsdf node. Whereas if I reverse the TransparentBsdf and DiffuseBsdf nodes, nothing goes through the TransparentBsdf node and I don't get any light from the spotlight.

I think I have addressed the amount of light issue by better positioning the gobo and using a more uniformly bright image as the imagemap, but I'm still getting basically only one color. I currently have a hi-res sphere primitive as the gobo, parented to the light, positioned with xTran 0, yTran 0, zTran -0.55 (my units are Feet). I've tried scaling both the sphere and the imagemap up and down, but the projected light doesn't look anything like the image, it just looks uniformly colored.

It looks so difficult, if possible, to simulate gobos using P12. I also have an product called "IDL Lighting rig" I think, with pretty much cool effects:

I'm not astonished if Blender has a specific Gobo object

And something that would be really cool: the possibility to add objects defined externally, through a concept of plugin, even if it's slower, but that's something that should be designed in the heart of Poser, similarly to the internally defined lights.