Lighting Channels is a feature of Photorealistic Rendering packages which allows you to group lights and adjust and balance them directly in the rendered image – without having to change the lights in the Geometry and
re-render the model. This is much faster, and using sliders to directly modify the effect of the lights and see the changes immediately makes it much faster to balance lights.
the first time you use lighting channels it is handy to isolate the individual channels (turn them on one at a time) to see just which light sources are effected by the channel
In this first image, I turned off all the lighting except the sun.
This lets you see the direct sunlight both outside, and through the windows. And also to see which items are lit indirectly by reflections of the sun light.
Channel 7 in this model is used only for the parts of the hanging light which directly illuminate the ceiling.
Isolating just this light is unnatural, but gives you an idea of what objects are illuminated by the up-light effect of these lights.
I started by turning the sun and sky way down, so that the interior lighting had more effect.
In viewing the image, I can see that I want to increase the Up-lights in channel 7 to have more of an effect on the ceiling, to increase the self glow panels (image on right wall) to make it appear to be back-lit, And to increase the lights outside the windows, (Channel 2).
I will adjust each of these one at a time, and I may have to readjust the first ones and the later ones make the overall scene brighter.
Here is a YouTube Video showing the use of Lighting Channels with this same model