I've encountered a similar problem before and my apologies for asking again.
I'm trying a technique whereby I draw with oil pastels on clear plastic, photograph it and import into AM for use as a Cookie Cut decal.
I made a little run sequence, converted it to png files with a background in each frame of pure white ( 255,255,255 ) applied that sequence to a flat with the white selected as the key colour.
The first frame was as expected
The second came out solid rather than cut
I will go back tomorrow and convert them to alpha backgrounds but, in the meantime, can anyone kindly suggest what the problem might be ?
regards
simon