NegaFix: How to avoid saturation?
PostPosted: Thu Nov 12, 2015 7:10 pm
Good evening,
several of my scans of color negatives saturate in the R-channel and I am looking for a way to avoid that. I guess, this is a problem not specific to my films but is of general interest.
For positives it would be trivial, since I could reduce the analog gain. However, the analog gain is deactivated for negatives (I assume to keep the reference to the NegaFix profiles).
One would think that an obvious way out would be to scan the negatives with film type set to positive into a raw file and then, once loaded into HDR, switch to NegaFix there. I tried that and first compared the raw files, the one scanned with film type positive to the one scanned correctly with film type set to negative. As expected, the two raw files are identical (to within the noise), since they are raw files.
However, the colors obtained in HDR from the positive scan are markedly different from the colors obtained in the "regular" way, i.e. scanned with film type set to negative:
So I have two questions:
1) Why does one get different colors, if the raw files are identical? What do I do wrong?
2) Since the workflow described above does not seem to work, how can I avoid saturation in scans of color negatives?
Hermann-Josef Röser
several of my scans of color negatives saturate in the R-channel and I am looking for a way to avoid that. I guess, this is a problem not specific to my films but is of general interest.
For positives it would be trivial, since I could reduce the analog gain. However, the analog gain is deactivated for negatives (I assume to keep the reference to the NegaFix profiles).
One would think that an obvious way out would be to scan the negatives with film type set to positive into a raw file and then, once loaded into HDR, switch to NegaFix there. I tried that and first compared the raw files, the one scanned with film type positive to the one scanned correctly with film type set to negative. As expected, the two raw files are identical (to within the noise), since they are raw files.
However, the colors obtained in HDR from the positive scan are markedly different from the colors obtained in the "regular" way, i.e. scanned with film type set to negative:
So I have two questions:
1) Why does one get different colors, if the raw files are identical? What do I do wrong?
2) Since the workflow described above does not seem to work, how can I avoid saturation in scans of color negatives?
Hermann-Josef Röser