… for Visual Effects

Tip #403: Blue or Green: Which Keys Better?

Larry Jordan – LarryJordan.com

Green and blue background yield different results.

This article, written by Charles Yeager, first appeared in PremiumBeat.com. This is an excerpt.

Chroma key compositing is the actual technique of layering two images together based on color hues. The solid color background essentially acts like a matte for your footage. Later, in post-production, you can remove the solid color background to make it transparent, allowing for compositing.

We use green and blue backgrounds because they are the furthest colors from human skin tones. But the two colors don’t give the same results. In an EXCELLENT article, Charles Yeager explains when to use green and when to use blue backgrounds. Here are the highlights:

Green Screens Pros:

• Results in a cleaner key because digital cameras pick up more information
• Requires less lighting
• High luminance is good for daytime scenes
• Uncommon color in clothing

Green Screen Cons:

• Color spill can be too heavy, especially on fine details and edges (or blonde hair)
• High luminance is not great for dark or night scenes

Blue Screen Pros:

• Less color spill is great for subjects with fine details and edges
• Lower luminance is good for dark or night scenes

Blue Screen Cons:

• Requires more lighting, which can be expensive
• Common clothing color, making it difficult to key in post