You could try advanced blending options:
double click on a layer, that will bring up the layer styles dialog.
go to the bottom, in ‘blend if’, select blue if in RGB, cyan if in CMYK.
try dragging either slider until the blue dissapears.
Why not just erase the background on each frame, letting the master background show through?
When I erase the background there always seems to be a little edge against the skier since the quality of grabbed frames isn’t the best. This makes it look like I just cut and pasted. This does work just fine if the skier is against nothing but the sky but if part of the skier overlaps you can see the blue tint around the edge. I’ll try the advanced blending, I’ve never heard of that. Thanks.
Zoom in tight and erase with a feathered brush.
What about masking with radial black-white gradient followed by a similar linear gradient sequentially? The first should create the transparent halo and the latter more of a blend. You could then touch up with a brush and/or slight blending effects later. Give a few guassians to any broad areas of non-essential pixels beforehand. You could also duplicate the layers as a first step and apply some motion blur as a base to each layer, further lessening the need for guassian later and making the transition from crowd/ground to sky more natural. In this way you can play with the "shakiness" of your existing frames as an effect. Experiment with the radii of the masked gradients to reveal just the right amount of subject.
How about trying the DIFFERENCE blend mode? The parts that are identical will be black. Start by Difference-blending just the top two layers. Then Difference-blend that result with the next layer, etc. I would hope you would end up with just the skier in as many positions as you have shots against a black background which you can leave alone or fill with any other background of your choosing.
I have tried the DIFFERENCE blend mode but it takes to much of the image away. Example: The shirt of the skier. When I use the difference mode the shirt which is white against the blue sky turns blue. So after I have changed all the layers to difference I am left with a great looking sequence except that all the shirts look like the sky with just an outline of where the shirt used to be. It’s so close. Should I maybe change the shirt color and see if that makes any difference. Other than that, this seems to be the effect that I am after. Are there ways to change the settings of the difference mode? I also tried the "blend if" idea and once again, so close. I’ve tried the sliders in ever combination and it almost works and then parts of the skier start to disappear. Could the way the pros use really be painstakingly erase the background from every frame?
Thanks for the ideas. I will keep trying! Please let me know if you think of anything else.
