Colors panel.

The Ramp button activates a color ramp which allows you to remap the colors of a texture to new ones. See Ramps for information on using ramps.

The color of a texture can be modified with the Brightness, Contrast, and Saturation buttons. All textures with RGB values, including Images and Environment Maps, may be modified with the RGB sliders.

R, G, B
Tint the color of a texture by brightening each red, green and blue channel.
Change the overall brightness/intensity of the texture.
Change the contrast of the texture.
Change the saturation of the texture.