What is the best way to remove blue screen from images that are a little soft? I had some people shot against a blue screen and they are not totally in focus, which is ok in the end , because where I am putting them, they are going to be out of focus. But this does make it a little more difficult to cut them out. If I use color range, it leaves a slight blue halo in certain areas. Magic wand does not work either, because once I blur the mask, I still have some blue over spill, and I do not want to choke the mask. These are 16bit, so I can not use the extract. Any suggestions or tips on the fastest and most effective way to get rid of the blue screen and the blue spill into the transitions?
Make the best masks you can and worry about the blue halo only when all images are at their final location on their own layers. You may have to make a new layer on top, set to blend as hue and paint the new background color on it, over the blue fringes.
As a good starting point, since your background is blue, hopefully the subjects aren’t wearing much of it. Go into channels and duplicate the blue channel. then invert the channel (cmd-i). what your left with is a mask that should mask out much of the blue and keep your subject on its own. you can then use levels/curves to refine the mask and use your paintbrush tools to get rid of or add to the mask.
I would make an 8 bit copy of the image, run extract, and then convert back to 16 bit. Then incorporate the result back into your 16 bit master document.
Obviously, you won’t be preserving the bit depth of the this part of your image, but if you do all your color corrections, etc. BEFORE you go to eight bit, no one, including you, will notice the difference. In Photoshop, 16 bits does not give you any more range, it just gives you more fidelity within the range you already have. So don’t worry about it!
There are also plenty of spill suppression plugins, for free and for a price.
To take c watt’s suggestion one step further: you could do the extraction on a duplicate file which has been changed to 8-bit mode. Cmd, click to load a selection from the extracted image; make a layer mask, select it and drag the Layer mask Channel into your 16-bit file.
However for this sort of shot, where the mask has to mask a particular color, you could do better with the Magic Eraser.
Work on a duplicate layer.
When you have erased all of the unwanted blue, Cmd. click on the erased layer to make a Selection and use that to create a mask on the original layer.
Then delete the "erased" layer and touch-up the mask as necessary.
Ann and C Watt’s : Chris cox and others recommand not to do that way: extract has another function: color decontamination, wich might be useful in this case.
I know that there is a full chapter about blue/green screen in the old but venerable "Photoshop Channels Chops" by Biedny, Moody and Monroy
