Certain colors not showing on Cycles Render I was recently working on a character model, and I encountered a problem while using the Texture Paint mode.
I unwrapped and assigned a texture to every piece of the model, and then went to the Texture Paint mode to work on it. When I finished the work I rendered it to check the result, and then I noticed certain colors of the texture didn't appear at all in the render.
The flat texture and the model in 3D view look like this:


Whereas the render looks like this:


For further reference, I'm using Cycles Render, and used the node editor to apply several shadings and displacement.
For the scene, I'm using two spotlights, both white in color, and black background.
Also, while in Texture Paint, I used the Multiply and Lighten blends for adding contrast, and the Overlay blend for applying the purple hue.
I'm using Blender 2.74.

Here is my node setup
You are using a mathematical multiply. You should be using an RGB multiply 

You can get the color multiply in the add menu Shift-A>Color>MixRGB and set the drop down the multiply.

The reason the math multiply doesn't work is that it simply multiplies a single value (per pixel) together, giving one output channel. The Color multiply multiplies each of the three channels (per pixel) and gives a three channel output.

This is how a multiply RGB node works, using the mathematical multiply:



Each color channel on the first image is multiplied by the corrosponding one on the second image. They are then added together to make a new image.

The factor merely mixes the multiplied image with the un-affected image.