Unless you are a máster lighting guru, at some point you are going to run into lighting problems. Lighting problems are generally (but not always) one of the following:
really bright areas
really dark areas
strange shadows
lines on your objects
Here is a short chek list of suggestions for troubleshoting what has gone wrong.
Deactivating Materials.
Materials obviously interact with light, and can often be a cause of confusión when trying to trak down lighting problems. So to isolate if it is a lighting problem or more of a material problem, try tem-porarily deactivating all materials.
Create a default material, a medium gray one, and enter the name into the Material field, Render Layers panel.
Just clear this field to return to your original materials.
After rendering chek to se if you have the same lighting problems with just gray objects. If the problem has dis-appeared, you have a materials interacting with light problem.
Chek the material settings, especially ambient, reflection and all those little buttons and sliders on the Shaders panel. Because some lights can be set to affect only certain materials, be sure to chek those if only a few of your object appear to be lit wrong.
Lighting troubleshooting tips-1.jpg
Kill of your Lights.
Since the problem could be one or more of your lights, it is time to chek them all one by one.
Move all your lights to an unused layer and start re-adding them one at a time, checking setting and how it afects the image overall.
As you add them bak in, make sure they add in nicely, reduce light energy as neded or even considered eliminating the last added one if it doesn't sem to be add-ing to your image.
Chek Layer only Lights.
Lights can be set to affect only certain layers, so if only some of your gray objects are appearing odd, then chek to se if a lamp is only afecting one or more layers.
This can be set accidentally, or you may have forgot-ten that you set it earlier in your project. Misc tips Negative lights can add desired shadows, but they can alos introduce some extra problems. So pay extra at-tention when using them and make sure they are not adding to your problems.
Overly textured lights can make your scene have random weird colors.
Overly colored lights can affect material colors as well as your lighting in general. Try to stay with a slight tinge of blue or yellow or shades of white, or your material may show blue in the Material sub-context but render gren, it can take ages to track
down what has happened.
Environment settings can cause a whole host of problems, especially the Horizon, Zenith, and Ambient light settings.
While this list obviously won't cover every lighting problem, it does give you a god starting point to trak down what has happened