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I'm just trying to work out how to make a profile for my film scanner. If I were to get a calibration target slide and make a profile from it, how would I be able to use it for both negatives and slides?
Many thanks for any help.

Sorry, I didn't log in.

Aren't negatives and sliders physically different image sources with different grains? If that is the case then you need separate profiles for negatives and slides I believe.

You'll certainly need seperate profiles for slide vs. negative film. The grain structure and density are vastly different.

If the cells on the calibrated slide are large enough, it would make an excellent NI calibration target. I suspect they may be too small to produce good low frequency data.

FWIW, I have seperate profiles for each variety of slide film I use.

-Greg

Thanks very much for the help.

FWIW, I have seperate profiles for each variety of slide film I use.

Yes that would be ideal. Unfortunately all the slides and negatives I'm scanning are from the past as it were.

What I was hoping to do was to have a profile of the general noise from the scanner itself rather than the grain from the film. Run all scans through neat image using this and then fine tune individulal scans where needed. In my mind this seems feasable but maybe not.

Thanks again.

I am afraid a profile for pure scanner noise and a profile for scanner noise plus film grain would be quite different. In this case, simple fine-tuning would probably not provide enough accuracy. Anyway, you could try and see if this is the case.

Vlad

I ordered a calibration target anyway so I'll experiment when it arrives and post the results.
Thanks again.

royalbox wrote:Thanks very much for the help.

FWIW, I have seperate profiles for each variety of slide film I use.

Yes that would be ideal. Unfortunately all the slides and negatives I'm scanning are from the past as it were.

What I was hoping to do was to have a profile of the general noise from the scanner itself rather than the grain from the film. Run all scans through neat image using this and then fine tune individulal scans where needed. In my mind this seems feasable but maybe not.

Thanks again.

Since chroma (Cr, Cb) noise seems largely scanner produced, your idea might work if you run only chroma reduction with the 'scanner' profile. Chroma-only noise reduction is actually quite helpful, although you'll probably want to run at least some Y reduction as well.

Luminance noise is found in both the film and hardware. Seperating them is probably not very practical. It's arguably best to profile film and scanner as a unit.

As for scanning boxes of old, unknown, slides, I sometimes produce a per-box NI profile using sections from several negatives from the same roll/box. (Device Noise Profile Tab > "Load test image") It does take a bit of time, but the results seem worth it.

-Greg