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Old 24th November 2011, 01:51   #582  |  Link
johnmeyer
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Join Date: Feb 2002
Location: California
Posts: 2,691
Quote:
Originally Posted by Jan Evertsen View Post
I have a nice clean black&white transfer but it is very grey. When I use Johns script I can adjust the whites and blacks but the results are a bit unnatural, like the shadows in this baby's face.

Does someone have an advice to 'smoothen' this effect?
My answer to that is similar to what I've posted before: AVISynth is not necessarily the answer to every problem. In this case, my approach is to do most of the "levels" work inside my editing program (which is Vegas). This program has a "Color Curves" interactive fX which lets me draw a Bezier transfer curve that alters the exposure of the film, but with a different gain applied to each level. Most film to video transfers result in video that is too dark in the shadows, a little dark in the midtones, but just right or a little too bright in the lightest areas. Each scene typically requires slightly different exposure correction. So, I apply a "generic" gamma curve, using this color curve fX, to each scene, and then, using a calibrated monitor and the built-in real-time histogram, I interactively tweak the exposure while watching the instantaneous results on both the monitor and histogram displays.

I do not use any of the automatic levels or color correctors built in to VideoFred's script.

Here's what the color curves dialog looks like, in case my description above doesn't make sense:



I'm using this exact dialog right at this moment to correct a 1933 amateur 16mm silent film that I'm restoring for a French documentary director.

I wish I knew of some autogain function in AVISynth that would do this, and many people have certainly tried to produce such a thing. One such plugin that I used quite a bit, before I discovered VideoFred's work, was the "High Dynamic Range Automatic Gain Control" plugin. You can search this forum and find the plugin. Try it out, and perhaps it will do what you want, without having to do all the manual labor I describe above. I think it has been updated since I last tried it.

Last edited by johnmeyer; 9th October 2019 at 16:48. Reason: Added sentence about not using automatic levels; Later, Replace degraded Photobucket images
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