1. What is it? Color cast is a tint of a particular color, usually unwanted, which affects the whole image evenly. Certain types of light can cause film and digital cameras to have a color cast. In general, the human eye does not notice the unnatural color, because our eyes and brains adjust and compensate for different types of light in ways that cameras cannot. In film, color casts can also be caused by problems in development. Improper timing or imbalanced chemical mixtures can cause unwanted casts.

2. When do I do this? When there is an unwanted color present in the image.

3. Instructions in Gimp Go here: How to Remove Color Casts With GIMP | eHow.com http://www.ehow.com/how_8451262_remov e-color-casts-gimp.html#ixzz1n8ATPBLlHow to Remove Color Casts With GIMP | eHow.com http://www.ehow.com/how_8451262_remov e-color-casts-gimp.html#ixzz1n8ATPBLl