#1  
06-30-2019, 06:50 AM
koberulz koberulz is offline
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I'm constantly running into this issue, which I think is red and blue clipping? Luma seems to be fine, but the only way I can get the red and blue back into range is to almost entirely desaturate the picture.

Original frame attached, as well as a Color Tools histogram from my result, which is after running ColorYUV(off_u=-11,off_v=2,cont_u=-50,cont_v=-50).

Any thoughts?


Attached Images
File Type: png frame.png (553.2 KB, 17 downloads)
File Type: png histograms.png (7.5 KB, 21 downloads)
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  #2  
07-01-2019, 03:43 PM
traal traal is offline
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In the gradation tool, try pulling the upper right corner of the Red channel's curve down until red's peak in the histogram matches green's. Similarly, pull the lower left corner of the Blue channel up until the histogram also matches green's. Then sample some RGB values in the image of what should be neutral (white/grey/black), and check with your eyes for any color cast. (A calibrated monitor is useful here.) Also use the vectorscope to check skin tones.

Judging by the histogram, the scene could also use a little more contrast, maybe. Try it and see if it improves the picture without clipping anything.
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  #3  
07-01-2019, 04:23 PM
koberulz koberulz is offline
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I'm not trying to fully color-correct, just to make sure I get all the data pulled into Premiere for when I do the actual grading, without having anything clipped.

It's an issue that's shown up on a bunch of different tapes, so advice relating to this specific frame isn't so much what I'm after as methods to get rid of what I assume is clipping in the red and blue channels. Anything I do to one makes the other worse, unless I pull all the contrast and/or saturation out of the image.
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  #4  
07-01-2019, 06:11 PM
traal traal is offline
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Can you import the video into Premiere as YUV?
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