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I shoot film in both colour and black & white. Currently I have the negatives developed and scanned by a lab. My next step will be to get a 35mm film scanner and scan the developed negatives myself, which will save some money in the long run (and it's also out of pure interest). I've been reading up on colour calibration for scanners and how you can make a proper exposure of an IT8 target. This would allow you to make a slide that can serve as a calibration target for the scanner and the film's characteristics.

My two questions are:

  • Is it possible to do this for colour negatives? They need to have their colours inverted and have an orange mask which must be factored out, so is it even possible to have such a calibration target for a negative? Or can it only be done for a positive? Do you have to rely on provided profiles such as NegaFix in SilverFast or can you create those with a proper shot of an IT8 target?

  • Is this relevant for black & white? Colour temperatures won't matter there, but do you need to calibrate for, say, a proper 18 % gray value to get a good base image to adjust levels on?

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In the case of a film scanner, an IT-8 target is a slide of known colours that you scan, and then you use software to analyse the scanned image to compare with those known colours. This characterises the colour-reading ability of your particular device, and allows a customised colour profile to be generated that can be applied to subsequent scans of positive material in order to "correct" them.

As you say, with negatives, there are also the considerations of removal of the orange mask and inversion of the colours. The orange mask is unique to each emulsion type (and even batch?) IT-8 calibration is not generally seen as very helpful for scanning negatives, and even when scanning positive material, it very often will not save you some editing in order to achieve "perfect" results.

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  • \$\begingroup\$ Calibrating with a target will not only correct the scanner's characteristics but also account for the film emulsion used, though. So calibrating your scanner with a positive IT8 slide isn't very useful for getting better results of colour negatives. Is it possible to have something like an IT8 target with a colour negative? What about calibrating for B&W, is there an option for calibrating gray values? \$\endgroup\$
    – G_H
    Commented Jan 28, 2019 at 7:34
  • \$\begingroup\$ IT-8 targets are produced in controlled environments. You can't just make one by photographing the IT-8 pattern using any film, and then use that film for subsequent "correction". Because every subsequent photo will be corrected to whatever random lighting conditions were present when you made your calibration photo. Or in other words, the colours in your calibration photo won't be "known colours". You buy the IT-8 slide ready for use, and I've only ever encountered them in the context of scanning positive material. \$\endgroup\$
    – osullic
    Commented Jan 28, 2019 at 9:09
  • \$\begingroup\$ @G_H On a related point, why do you want to "correct away" the unique colour characteristics of whatever film you are using? That's one of the nice things about different film emulsions is that they each have their own colour palette. I wouldn't expect you should want to neutralise this. \$\endgroup\$
    – osullic
    Commented Jan 28, 2019 at 9:10
  • \$\begingroup\$ If you are unhappy with your scanning software's process of removing the orange mask and inverting the colours, you could look into the ColorNeg plug-in. I researched it a bit myself, but ultimately decided that it wasn't necessary (admittedly without ever actually trying it). \$\endgroup\$
    – osullic
    Commented Jan 28, 2019 at 9:18
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    \$\begingroup\$ Another alternative worth considering if you are shooting a significant amount of exposures in the same conditions... Use one exposure to shoot something like a ColorChecker Passport (or even a WhiBal or QPcard). Then just trust your scanner to do as good a job as it can, and leave your colour adjustments until your editing phase. With such a reference in the frame, it's easier to get good colour in one image, and batch-transfer adjustments to other images. \$\endgroup\$
    – osullic
    Commented Jan 28, 2019 at 13:22

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