color correction help needed

[Billman]

Can anyone recommend some kind of tutorial on color correction of
scanned film negatives? I've been using Vuescan (8.0.8) to produce
Raw files from my Epson Perfection 2400 and using the following
workflow in Photoshop Elements 2.0:

(1) Rotate (if needed) and invert
(2) auto color-correct (seems to be the same as doing each channel
individually)
(3) boost the saturation (the raw scan is too flat)
(4) slightly sharpen
(5) save a TIF and JPG.

I think the resulting images look pretty good, but when I compare them
to the original hard print image I see the colors are way off. The
blue channel is too vivid, for example, and I can't quite get skin
tones correct. It also seems like the contrast of certain color
channels is compressed; the green leaves of plants, for example, are a
nice dark green in the photo but turn out much brighter in the
scanned. It's almost as if increasing the saturation is the wrong
thing to do overall, but I don't know how else to improve the
vividness of the "flat" scans.

Does anyone have any suggestions? Thanks in advance -- Bill

 

[degrub]

Have you attempted calibration of your monitor ? There are several free
programs around , such as adobe gamma, that will let you get closer on
what you see on screen. Or you can buy Photocal or equivalent and
profile your monitor. The second thing to do is get an IT8 reflective
target and use the profiling capabilities of Vuescan (you may have to
upgrade) to help get the colors closer and more balanced. Wolf Faust
sells very good quality for a reasonable price.

http://www.targets.coloraid.de/

Part of the difference you are seeing is the difference between
reflective and transmissive media. Part is how your scanner is seeing
the dyes on the film. Have you used Ed's advanced work flow to lock down
the base color of your negatives ? Try looking at these websites for
general scanning advice:

www.scantips.com

www.luminous-landscape.com

www.computer-darkroom.com

You can also look at a copy of Katrin Eismann's book " Photoshop
Restoration and Retouching" for guidance.

Frank

 

[Billman]

Thanks, Frank --

Yes, I do follow the VS recommended workflow, and I haven't yet taken
the step (or expense) to calibrate my monitor beyond Adobe Gamma. (I
do intend on getting the Wolf Faust target, though, so thanks for the
link.)

I recognize that there's a difference between the reflective photo
media and the transmissive screen image, but I think this is just part
of my larger educational need. What I am looking for in a tutorial is
to learn answers to "if skin tones are too orange, do this", "if the
greens are a little flat, do that". I'm still a novice at this kind
of thing, so I'm looking for help on how RGB channels combine to
produce the colors I see on my screen (and, hopefully, then relate
those to the reflected colors of my prints).

Interestingly, I changed my workflow yesterday and discovered some
settings that gave me colors closer to what I saw on my hardcopy
photos. I used VS to produce raw files and then used VS to scan from
the files; to correct the colors, I found that if I

(1) reduced the overall brightness
(2) checked "restore colors"
(3) boosted the brightness red to 1.25
(4) reduced the brightness blue to .8
(5) and left green unchanged

that I obtained scanned images that looked pretty darn close to the
original photos. Which really makes me question - with dismay - the
colors of all the negatives I've previously scanned. :-(

But it's a learning process. I find it interesting how my workflow
and approach changes/evolves as I plod through a 4" binder of
negatives. The scans I'm getting now are a huge improvement over
those from the start of my project.

Thanks again for your suggestions.

Bill

 

[degrub]

In that case, look at any one of Dan Margulis books "professional
photoshop X (=4 to 7): The Classic Guide to Color Correction". You
should be able to get one used for a reasonable price. He covers how to
scan by the numbers (RGB, or his preference CMYK) to get good skin tones
etc and how to do color correction. His method works as it has been used
in print shops for years, but it does take some practice.

Frank