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An Artist
01-14-2006, 01:57 PM
Hello,

I want to chroma key at home. I own a Canon Rebel XT, and a Canon Elura 80. I want to have PNGS of a person moving to put into flash. Therefore, I want to use my Canon Elura 80 to take video, convert them to stills, and animate the footage.

But what is the best way to do a chroma key at home? I don't have any lights or green screens.

Can anyone recommend what to do?

Thanks for your help.

blanius
01-14-2006, 07:57 PM
use black background and do Luma Key instead

An Artist
01-14-2006, 08:56 PM
use black background and do Luma Key instead


Thanks for the input. I must admit, this is the first I have ever heard of Luma Key. I have a lot to learn.

But this brings me to another problem. The people I will be photographing are going to be wearing dark colors. One person will have black hair.

Anyway around this?

robbmcaulay
01-14-2006, 10:06 PM
I have nooooooooooo idea what you're both talking about but common sense tells me that if you use a white background, invert the colours of the footage, perform whatever Luma Key is then invert it back...

Or have I got it all wrong? :D

Big Up Ya
01-15-2006, 12:58 PM
Chroma & Lumakey are both moving image terms and don't entirely apply to stills. The idea still works and is called deep etching or cut outs depending where you live. You need to shoot on either White, Chromablue or black background. Best is actually white for stills. I'd aoid black as you usually loose about a 3-5 pixel fringe from it whih results in a soft image. Blue is often used as there aren't many conflicting tones that you will find.

Then go into photoshop, use the pen tool and cut a path around the edge copy and paste to a new layer, selct your background and fill it any colour you need. Make sure the model is wearing clothes, and has their hair n a style that is going to be easy to cut out.

If your lighting is clean enough you can use the magic wand tool. Just play around with the tolerance levels (32pixels is default and normal - 1 pixel for each shade ie. if you want to select one shade, for example pure white, you put the tolerance on 1 and click on pure white)

You can use lasso if you want but it's going to look pretty crap unless you use the point lassoo and get in real close and have a fair bit of time and patience up your sleeve!

If you do use chromablue then you can use selective colour. Sample the colour and load it in. but it's going to in general loose it on shadows etc.

Pen tool is best. Resonably and relatively quick, completely editable and saveable. You can shoot it on any background you want this way though. Just make sure there arae no conflicting tones...ie black clothes on black bits of background.

You may need to feather on some things. Even as little as 1 or 2 pixels can help.

If you want to go down the backdrop roll route, get a colorama roll...pretty expensive though...from a pro photo shop.

Goodluck!