Shouldn't chroma key screen be blue or green?

Here's a link to a photographer who uses a white backdrop to separate his subjects from for compositing projects. I would think that masking a subject from a white background is not a good idea because the rim lighting highlights blend in too much with the background. Shouldn't the chroma key be blue or green?

http://web.me.com …f_difficulty_in​_post.html

On one of his other pages (portraits on white), he mentions that he's very careful to watch for clipping when lighting a white background so that he avoids light wrap.

Actually, for objects like the elements he used for that composite, I think over white is a very good idea. If nothing else, it avoids throwing a color cast of any kind.

He does some nice work, but I don't think he's using chroma key. For whatever image you're trying to make, you really should do a few tests with the subject & lighting you intend to work with. Then refine the results until you get what you want.

Since you used a descriptive title, the forum has done a mini-search for you. Look at the links at the very bottom left hand corner of this page, & you'll probably find more help in them.

If green/blue chroma keys cast undesired color fringes on the subject, then why do people buy green/blue chroma keys? I don't think I've ever seen a movie shot with a white chroma key. They're always blue/green.

I believe in the motto: Do as the successful do. And because Joel Grimes is successful at what he does, I'm tempted to forget the green chroma key and go with a white one instead. However, I can't stop from wondering why so many photographers use green screens instead. Could it be that Joel Grimes uses a software that works better with white chroma keys. ??

The green and blue are more suited to film and video because of movement. If you have a still object you are cutting out in PS. then you can theoretically use any color you want. Go purple if it works for you. The blue and green are used for movement because the special computers that use to be used for this task could calculate thes colors easier than others. They are also a special paint for the "Real" blue and green running 70 to 8o bucks per gallon.

I dont want to read each post here but i think using white is good as long as you dont have anything else to bright.

Makes it easier not to have color splash onto the subject and also when editting can use one of the blending layer modes to edit easly without having to crop out the subject or anything to difficult (Not saying what he did is easy but its just easier using white sometimes then using green or blue.)

Just my .02

He's not doing "Chroma Key" in this case. He's simply doing layer composites and white lets him cut out each element cleanly.

Blue or Green were originally used for CK in television because it was easy to drop the blue or green channel in a video signal. I've seen Blue, Green and even Red used but Red tends to clash with skin tones, Blue is often a clothing color which left Green as the most used color.

If you look at how F/X in movies are assembled, most of the matte work is done with black or white "hole cutters" or "HiCons" (short for High Contrast) created in the exact same shape as the object being layered. Pre Computer, the backgrounds were often hand painted (Google: Mat Painter or Matte Painter) and the HiCons were also painted by hand and everything was sandwiched in a special camera called an "Optical Printer" where all the layers were re-photographed together to make the finished effect.

There are some great F/X bloopers in the original Star Wars where X-Wing Fighters wink in and out of some scenes in the final battle because they missed a few frames of HiCon which blanks out the layer with the model on it.