James,
Thanks for the reply. I thought of using a very fine wire across the
corners and also of using a very fine fiber optic and LEDs to put dots
in the corner. So far, with the images I have tried, it is easy enough
to register them. There is always several edges to use. My problem has
been more like dimensional stability but caused by not having film flat
in the scan. So I am hoping oil mounting the scans to get them flat will
help solve it. Whether flatness in the exposure is an issue I cannot say
yet. My hunch from results so far with sheet film is it may not be that
big a problem. The related issue is angular displacement between two
separation negs. Doing the scans as a strip of three separation
negatives on roll film ought to assure little angular displacement but I
won't know until the mounting fluid I orders arrives out here in Taos.
There used to be pin registered camera backs where you pre-punched sheet
film but I have not been able to find one. Aligning in linear
displacement (X & Y) is pretty easy in Photoshop but at least my old
Photoshop 7 makes angular displacement an issue.
I imagine most people on this list have seen the Russian tricolor
exhibit at the Smithsonian website.
http://www.loc.gov/exhibits/empire/making.html
http://www.loc.gov/exhibits/empire/
These photos seem so remarkable. When we do get to see early photos they
are always in B&W. To see photo journalistic photos shot between 1905
and 1915 in color is quite unusual. I wish I knew how his camera worked.
It appears that the back had to do with shooting the tricolor exposures.
And judging by the large number of well registered people shots it must
have allowed the three separations to be shot in rapid succession. What
further baffles me is that I thought only orthochromatic film was
available back then. In the movies they were powdering faces white to
get lighter complexions in B&W movies yet here he is shooting tricolor
separations that have lifelike skin tones in color so he must have had a
good red neg. Be sure to scroll down to the bottom two images and zoom
them up to see what incredible color his separation negatives were
capable of. Talk about Kodachrome color! If you compare the spectral
curves for modern digital sensors to what is possible with either the
25-58-47B or sharper cutting 29-61-47B tricolor sets it is easy to see
color separation is about as good as it gets doing in-camera RGB
separations and that the modern way has huge overlaps in color and thus
color purity in comparison.
It is because he shot these on B&W film as tricolor separation negatives
that we can view them today. Any other form of color film would have
faded away by now. And we will have to wait and see how many digital
images do survive. Sony recommends re-recording or refreshing disc media
every 50 years. Since I built my first microcomputer in 1978 I have had
5 1/4" hard sectored floppies, 8" floppies, IBM 5 1/4" soft sectored
floppies, 3 inch rigid floppies, Iomega discs, CDs, DVDs and now
something like BluRay will be taking over for storing images I guess.
I'd be hard pressed to recover images from most of those digital storage
formats now, so that film does not look like such an archaic choice if
archival access and precise color are significant issues. I have heard
that historians worry that we will have far better visual records of the
1800s and 1900s than we will the 2000s because digital is replacing film
and access archivability is approaching an instant just as shot access
has become instantaneous with digital cameras. Collectors worry about
print lifetimes but for photographers and artists it is the original
media that ought to be archival.
Ed Scott
James Schenken wrote:
Ed:
Never did Tri-color in camera myself but it seems that the registration
problem may be related to movement of some kind between shots.
So.. if it within your capabilities to make a glass insert to place very
close to the film plane ( easier in the 4x5 ) that has index marks engraved
in the corners similar to ones that NASA used on the Moon landing
photography, this might make it possible within Photoshop to both adjust the
positioning of the image and to tweak the sizes so that the overlay is
better aligned with respect to position and size.
The black lines of the indexing marks would have to be spotted out in the
Photoshop process but that should be relatively easy.
Best of luck on this difficult project.
Cheers,
James
-----Original Message-----
From: owner-photoforum@xxxxxxxxxxxxxxxxxx
[mailto:owner-photoforum@xxxxxxxxxxxxxxxxxx] On Behalf Of Ruey
Sent: Wednesday, December 16, 2009 7:51 PM
To: List for Photo/Imaging Educators - Professionals - Students
Subject: New to forum - interested in in-camera tricolor on film
I live in Taos, New Mexico where there no longer are "any" photo labs. So I
have been experimenting with shooting in-camera tricolor on 120 and 4x5. I
can process the film in D-76 and scan it on an iQsmart3 to convert to RGB
image in Photoshop. I am using the sharp cutting tricolor filter set - 29
red, 61 green and 47B blue. Registration is an issue. I am going to try oil
mounting the three shot RGB 120 strips to see if that helps. I use Tri-X,
TMAX and Rollei IR films. I'd be interested in hearing suggestions from
others who have shot in-camera tricolor on film.
No digital suggestions please. I am only interested in in-camera tricolor
with film. (I worked as an R&D engineer on digital imaging systems most of
my life and in my retirement, for as long as Kodak et. al. permit, want to
keep using film.)
Ed Scott
