Flickering in photos...

Question

Hello - I know I have approached this before, I had asked about pictures 'flickering' when given keyframes in Motion - I was told to apply the Flicker filter and to set it on Minimum. It still seems to flicker though - what is causing this? Should I try another filter, like De-Interlace? It seems to do it on a lot of the pictures - ok, thanks!

Answer 1

The flickering you see is an artifact of the interlaced nature of video. It is a result of either very thin (often horizontal) elements that exist on one scanline as is common in text/ titling or scanned images with a great deal of detail in high contrast. (Note: It does no good to import images hugely larger than the necessary pixel dimensions of the video sequence. All it does is force FCP to work harder at interpolation.)
As the alternate fields play, the offending element is essentially being turned on/off creating the impression of a flicker. The basic strategy is to get the element to exist over two scanlines so it is refreshed every time the field plays and/or to reduce the amount of contrast so the difference between ON and OFF is not noticeable.
Things to try (In increasing order of image degradation)
° (in FCP) field order>none
° (in FCP or Photoshop) reduce whites by 10% - reduces overly bright areas
° (in FCP) flicker filter - minimum
° (in Photoshop) motion blur>vertical> .2 - .5 pixels - blurs vertically only
° (In FCP or Photoshop) Gaussian blur> .2 - .5 pixels -blurs both horizontally as well as vertically
° (in FCP or Photoshop) deinterlace - throws away half the image and is generally not appropriate on scanned or still images.
One neat trick is to use the selection tool to limit area you apply the vertical and/or gaussian blur to only the troublesome part rather than indiscriminately soften the entire thing.
Remember: Unless you are viewing your work in the appropriate external NTSC/PAL monitor, you are playing blind. The computer monitor only shows you a proxy image.
good luck.
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