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Author Topic: Colour (color) neg  (Read 1900 times)

alex

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Colour (color) neg
« on: March 10, 2016, 06:27:00 am »

Does anyone know of a suitable curve or preset for using colour (alright, color) neg in Lightroom? Making one for b/w was easy enough, but with colour there's the issue of the orange mask (which also varies between different film stocks).

Thanks,
Alex
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Alex Ramsay
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Bart_van_der_Wolf

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Re: Colour (color) neg
« Reply #1 on: March 10, 2016, 09:11:07 am »

Does anyone know of a suitable curve or preset for using colour (alright, color) neg in Lightroom? Making one for b/w was easy enough, but with colour there's the issue of the orange mask (which also varies between different film stocks).

Hi Alex,

I don't know if you can get a better source scan, one in which the mask color was removed by using appropriate (different) exposure times for the R/G/B color planes. By using a better/filtered lamp color or adjusted exposure times, the mask can be neutralized.

If you scanned source image still has a mask color, then it must be removed in postprocessing in linear gamma space, but that will have a lower quality due to underexposed Green and Blue channels or a clipped Red channel. Since LR Process version 2012 the tonemapping has become significantly non-linear which will cause problems if you try to remove the mask color. Therefore I'd recommend using the Process version before 2012.

Then use different RGB white points to neutralize the shadows (whites in the negative), and adjust the black points (the whites in the negative) for mask removal. Then invert the image tones, and tweak the tonecurves for a nice(r) roll-off in the shadows and highights.

It is very unlikely that a canned curve will do a good job, because the mask density varies per processing run of the films, and the Mask neutralization is essential before inverting / correcting color and tonality, and needs to be done first. Also the non-linear response of Process version 2012 will cause a nightmare for color correction, unless the mask was neutralized by scanner exposure first, as it should (to avoid noise issues and color correction problems).

Cheers,
Bart
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alex

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Re: Colour (color) neg
« Reply #2 on: March 10, 2016, 09:19:15 am »

Thank you Bart, that's comprehensive and helpful. I should however have said that these are not scans, I'm simply making digital copies of the original negs

Alex
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Alex Ramsay
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alex

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Re: Colour (color) neg
« Reply #3 on: March 10, 2016, 09:33:14 am »

Presumably neutralising the film rebate should remove the mask?
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Bart_van_der_Wolf

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Re: Colour (color) neg
« Reply #4 on: March 10, 2016, 10:06:09 am »

Thank you Bart, that's comprehensive and helpful. I should however have said that these are not scans, I'm simply making digital copies of the original negs

Okay, but they can still be considered as if they were scans. The only tool you have to improve the Raw quality (mostly better Green channel exposure) in a single exposure, is then to use (magenta-ish) filtered light for the capture. Otherwise, the postprocessing remains as described.

Cheers,
Bart
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Bart_van_der_Wolf

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Re: Colour (color) neg
« Reply #5 on: March 10, 2016, 10:13:17 am »

Presumably neutralising the film rebate should remove the mask?

When the color negative film-base color (leader or between-frame or between-sprocket perforation) is neutralized, then the mask is removed from the image itself, and one basically only needs to invert the image.

Since Color Negative film is designed to work well together with C-print paper (which has its own characteristics), the digital negative may need some color/tone adjustment to taste, after inversion (and after prior mask neutralization).

Cheers,
Bart
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Tim Lookingbill

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Re: Colour (color) neg
« Reply #6 on: March 10, 2016, 06:03:55 pm »

Yesterday I came across this tutorial for converting a color negative in LR... https://www.youtube.com/watch?v=OQGtyR-imeI

Of course you need to start out with a scan that makes the negative look exactly as it does viewed back lit by daylight by examining it up against an open window. This also includes brightness and saturation appearance as well...note the histogram representing the negative before the conversion at the beginning of the LR tut.
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alex

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Re: Colour (color) neg
« Reply #7 on: March 11, 2016, 08:51:00 am »

Thanks for this - it led me to a much better system from the same guy inverting each channel separately, which seems to give really good results. https://www.youtube.com/watch?v=zy7c2ikUhcM

Alex
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Tim Lookingbill

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Re: Colour (color) neg
« Reply #8 on: March 11, 2016, 12:16:59 pm »

Thanks for this - it led me to a much better system from the same guy inverting each channel separately, which seems to give really good results. https://www.youtube.com/watch?v=zy7c2ikUhcM

Alex

Even better, and back at you thanks for finding and posting.

My caveat about starting out with an exacting replica of a properly exposed "good" negative I can't emphasize enough because I used to employ a similar method in Photoshop with various brands of negatives (Agfa 160/Kodak HD 400 shot 15 years ago) developed at one hour photo labs and didn't get as good results scanning with an Epson flatbed.

Now I'm seeing these YouTube tuts including others than the ones we've linked here and they get such great results quite quickly and I'm a bit suspicious on how they arrived at the scan and such good quality negatives. And we don't even know what color space it was scanned from and into by the time it's imported into Lightroom. Was there an embedded profile? Who knows?

Give it a try and report back if you get the time to let us know if it works with your negatives.
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