Archived posting to the Leica Users Group, 2006/11/28

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Subject: [Leica] IMG: Need help with C22 degs
From: hoppyman at bigpond.net.au (G Hopkinson)
Date: Tue Nov 28 16:04:47 2006

Len, as you know I sent you my attempt off list and a link to Julianne Kost 
at Adobeevangelists, where I learnt this approach. 
I'd like to add to the suggestions regarding setting the black and white 
points. I thought that this might be of interest to others
and maybe promote some discussion. I know that there are some Photoshop 
gurus on the list.
As was pointed out you can use thresholds to locate the darkest and lightest 
areas, then sample there. But unless those points are
truly pure white and black (which your monitor and print won't reproduce 
anyway) you are losing some tonal information there. That
becomes particularly important where the scan is only 8 bit (as in a jpeg). 
So you end up with gaps in your histogram, that is not a
smooth range.
So for a white, for example, firstly there has to be one in the image. Only 
a specular light source would truly be close. I'd
suggest that you look at the sampled RGB values, find the lowest value and 
then adjust the other two channels to the same value. Use
a levels adjustment layer. Now you've neutralised the highlight, Similar 
process for the darkest point.
For the mid tones choose a point that you think should be a NEUTRAL grey. 
You may not necessarily have or want exactly a mid-tone.
If you do set that point as say 133 and it wasn't close, you are altering 
the tonal range once again. It may not be bad, but it may
not be what was there, either. The important point is to adjust the three 
channels at that point to be the same value. Use a curve
adjustment layer.

The other point I mentioned off list is that, once you have established a 
corrected version, you can drag the adjustment layer to
other similar images where you have a number to correct.

Well let's see what our knowledgeable LUG folk think of these suggestions

Cheers
Hoppy
-----Original Message-----
From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org 
[mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of
Don Dory
Sent: Tuesday, 28 November 2006 14:24
To: Leica Users Group
Subject: Re: [Leica] IMG: Need help with C22 degs

Len,
You shouldn't panic, this is a relatively easy correction.  If using PS then
open an adjustment layer:levels.  Use the white point eye dropper on
something that should be white in the image; you can use the pointer to find
something near 255,255,255.  Then find something that should be black and do
the same with the black point eyedropper.  Most of the time the color gets
really close at this point.

This is your original:
http://gallery.leica-users.org/v/DoryG/On-the-road/OrchidIsland_1.jpg.html

and this is what happens after I did the above:
http://gallery.leica-users.org/v/DoryG/On-the-road/OrchidIsland_1copy.jpg.html

Possibly a little bit blue but pretty close to reality as seen by thirty
year old print film.  In actuality I would add another adjustment layer for
color and tweak in a little bit of yellow back.

Don
don.dory@gmail.com


On 11/27/06, Leonard Taupier <len-1@comcast.net> wrote:
>
> I have a large number of C22 color negatives from the 70's I'm trying
> to scan. I find it impossible to get the color right. I have spent
> hours with the following two images and they still aren't right. Does
> anybody know of a profile for Nikon scanners what will handle C22
> processed negatives?
>
> Nearly all my old negatives were taken in the Far East in Taiwan,
> Hong Kong, and off shore Islands. About two years worth.
>
> http://gallery.leica-users.org/v/LeonardT/Orchid+Island/
> OrchidIsland_1.jpg.html
>
>
> http://gallery.leica-users.org/v/LeonardT/Orchid+Island/
> OrchidIsland_2.jpg.html
>
> Thanks,
> Len
>



Replies: Reply from len-1 at comcast.net (Leonard Taupier) ([Leica] IMG: Need help with C22 degs)
In reply to: Message from don.dory at gmail.com (Don Dory) ([Leica] IMG: Need help with C22 degs)