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To correct the initial color balance and remove the orange mask of a scanned color negative we would normally set black and white levels to just barely clip each color channel. This works fine with shots that have both black and white points in them like those having, for example, a deep shadow under a tree and a blown highlight like a glare or a light source.

But how to correct the color and exposure of a negative that lacks either one of the points or both of them? The goal is to preserve the exposure, contrast and color characteristics of the original film shot without corrections.

Examples of the shots:

  • a sunset shot with the black shadows on the foreground and the orange colored Sun disk being brightest point of the frame - no white point in the shot
  • a shot of water surface with light reflections and no deep shadow details - no black point in the shot
  • a shot of a misty landscape on a heavy overcast day - neither black, nor white point in the shot

We could of course color-correct the images by feel, rely on the memory of the actual scene or use common objects for color reference, but here we want to preserve the lighting effects or color casts captured on a particular film stock that were present in the actual scene without any artistic intrusion. The same is true for the shots we have not seen in person.

Any artistic intrusion could be performed after the initial scan corrections, is optional and is out of the scope of the question.

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    What makes you think your current method does not constitute "artistic intrusion"? – user29608 May 18 '17 at 1:23
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I think the short answer is that you can't create an accurate color balance without the aid of reliable black/white/grey points and/or a color chart.

However, there are some things you can do to make the guesswork easier. Much of this depends on the scanning software and I mostly use Epson Scan which allows the user to pick white, black and grey points. These will go a long way towards balancing the color for you. Also remember that if you are scanning a strip of film (e.g. 135 or 120) you can use the values from a frame that has a suitable cue points to get values for your curves on another frame, at least as a better starting point.

I'm hopeful that others will have good tips for your problem since it is something I have to struggle with from time to time....

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Every scanned negative has true black (after inversion, of course) on the unexposed parts of the film strip around the frame.
If the goal is only to remove the orange mask, this is the place to get the best sample of the film base.
Similarly, the film strip will have a completely exposed part at the beginning for the absolute white point.

  • Excellent point. I wonder if the exposed frame numbers can act as the opposite from the unexposed base. Unfortunately, this doesn't help me much with my mounted slides. – user7264855 May 18 '17 at 16:57
  • Thanks for the suggestion! It was one of my initial approaches and I have been keeping all my film leaders for that purpose. Unfortunately, on practice it gave me extremely low contrast scans with tons of headroom both in lights and darks. But now I'm thinking it probably could have been a linear scan, which needs a gamma curve applied to it (which value?) to compensate contrast. – lightproof May 19 '17 at 19:55

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