artifacts on subject shot against red background

[Luca F Lucarini]

Hey all. I recently shot an r n' b singer against a pretty heavily saturated red backdrop that had a light shining at it from behind. I didn't notice anything during monitoring but when I dumped the footage into Final Cut I was stricken to see lots of artifacting along her head and shoulders where the subject met the background. There wasn't a problem with similarly saturated green, orange and blue background. Anyone know why this would be happening? Are there any remedies?

[Boyd Ostroff]

I haven't personally seen this problem, but what is FCP monitoring setup? Are you using a real HD monitor with a capture card? Or are you using digital cinema desktop with a computer monitor? Using digital cinema desktop I have noticed some strange artifacts which concerned me, but when I played the tape on my camera connected to an HD LCD monitor via component video, the artifacts weren't there.

Maybe your issue is unrelated to this, but I just wanted to mention that digital cinema desktop doesn't really display full quality output.

[Matt Davis]

Originally Posted by Luca F Lucarini

Are there any remedies?

Apply the two-way colour corrector to the clip and drag the saturation way over to the left, then nudge it back until you get enough colour to look nice, but not enough to amplify those huge great big colour sampling blocks.

Red is at the low wavelength end of the visible spectrum and so detail (edges in this case) tends to go fuzzy/blocky quicker than green and blue end of the spectrum.

[Luca F Lucarini]

ok guys thanks for the tips. i suspect it is a monitoring issue. if not than destauration should (hopefully) do the trick.