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Archive 2012 · Film scanning, auto color correction, and film (color) pr...
  
 
glee719
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p.1 #1 · p.1 #1 · Film scanning, auto color correction, and film (color) profile


Hello,

I don't know if someone can explain to me in laymen terms what does "auto color correction" do when a film is scanned? I occasionally ask for prints with development, and I use them as the reference when I scan the film into computer. For some reason, I could never get a good color when I disable color correction, so does it mean the film itself isn't capturing the real colors as our eyes see (well the negative part of them)? This doesn't seem to be an issue with chrome, but with c41 I always seem to need to auto correct color anyway. How does auto color correction work? Will I end up losing the character of the film I use if I auto correct everything?

Which brings me to the next question, then what's the point of selecting a film profile when scanning? It does change the colors a little here and there, but if I just end up auto correct the colors, is picking a film profile even necessary?

I am using VueScan.

Thanks in advance.



Jul 19, 2012 at 10:04 PM
Peter Figen
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p.1 #2 · p.1 #2 · Film scanning, auto color correction, and film (color) profile


Generally, the Auto setting in most scanning software looks for and finds the darkest and lightest area in your image and set them to a predetermined value - usually something like 10,10,10 for shadows and 245, 245, 245 for the highlight end. For a lot of images this works quite well, and is the basis of the first step in color and tonal correction in Photoshop. The Auto functions always assume that the highlights and shadows should be neutral, and if they really are, then it's a great thing, but when they're not, that's when the function gets fooled, and that's when you have to intervene intelligently, deciding whether that should be neutral or have a cast. More sophisticated softwares give you complete control over full, partial or manual corrrection.

The film profile serves a completely different purpose. It doesn't do any correction at all, but helps the scanner to reproduce the film "as is" including whatever nuances that give that film its character. It's always good to have a good scanner profile, as it provides the "source" profile for the conversion to your Photoshop RGB working space - the intermediate destination.

Almost every piece of scanned film can be improved on from what the actual film looks like, and that's where it's easy to get confused about profile and setting end points in the scanning app. It's entirely possible to do both and get even better results. The profile helps record the character of the film and the fine tuning of endpoints helps make your file look its best.




Jul 19, 2012 at 10:25 PM
glee719
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p.1 #3 · p.1 #3 · Film scanning, auto color correction, and film (color) profile


Thanks. The first part makes sense to me, the 2nd part doesn't because wouldn't a completely unmodified scan be most accurate to what the film is supposed to have? If I can change film profiles to get different outputs for the same frame, how am I sure what's the "real" character of the film versus what I like after selecting a profile?

In essence, I can be fooling the digital output to look a certain way when the film isn't supposed to be that way, no?

This started to bother me because I have a very red picture shot on Ektar and scanned on Coolscan V and VueScan. The digital version makes it pinkish unless I really screw with the hue and color temp. If I just want a raw scan without any modification, what should I do?

Thanks.







Jul 19, 2012 at 10:50 PM
 

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Peter Figen
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p.1 #4 · p.1 #4 · Film scanning, auto color correction, and film (color) profile


Well, there's really no such thing as a "raw" negative scan. Profiles for negative film like your Ektar are only approximations. You HAVE to make adjustments in the scanning software to make the image look how YOU want it to look on your calibrated screen. There is no reference for a color neg like there is with a color transparency, where you can just look at the film.

I scan a ton of color negs on my drum scanner, and I always start with the Auto setting and see what it looks like. Then I decide if the software found the right endpoints (it usually does but not always) and then decide if I want or need to override the software neutralizing the orange color neg mask. For example, if it's a sunset, the "white" point might be some sort of orange, and if you let the software neutralize and whiten it, your image is gonna suck. Same strategy with black point.

With your pinkish reds, you might need to use a Selective Color adjustment in the scanning app, if it's got that ability. It



Jul 20, 2012 at 04:26 AM
Peter Figen
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p.1 #5 · p.1 #5 · Film scanning, auto color correction, and film (color) profile


Well, there's really no such thing as a "raw" negative scan. Profiles for negative film like your Ektar are only approximations. You HAVE to make adjustments in the scanning software to make the image look how YOU want it to look on your calibrated screen. There is no reference for a color neg like there is with a color transparency, where you can just look at the film.

I scan a ton of color negs on my drum scanner, and I always start with the Auto setting and see what it looks like. Then I decide if the software found the right endpoints (it usually does but not always) and then decide if I want or need to override the software neutralizing the orange color neg mask. For example, if it's a sunset, the "white" point might be some sort of orange, and if you let the software neutralize and whiten it, your image is gonna suck. Same strategy with black point.

With your pinkish reds, you might need to use a Selective Color adjustment in the scanning app, if it's got that ability. You also could benefit from setting white and black points, which are really pretty far off in this image. Just doing that alone will clean up your reds considerably, but ultimately, it's a judgement call that you're going to have to make.



Jul 20, 2012 at 04:40 AM
glee719
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p.1 #6 · p.1 #6 · Film scanning, auto color correction, and film (color) profile


Thanks for the advice. I will play with it a little more.


Jul 20, 2012 at 02:19 PM





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