[filmscanners] RE: Grip and Stretch film holders

["Laurie Solomon" <laurie@advancenet.net>]

>I used to use a 4x5 film holder with a Beseler enlarger which gripped
>two opposing edges of the film and stretched it tight to avoid
>sagging and reduce buckling during exposure.

I have and use one of these.  They are big and heavey, being made out of pot
metal and containing the clamping mechanism with its clamping lever.  Unlike
most scanner film holders which are made of lighter materials and smaller in
overall size for any given film format, such a film holder for a scanner
would be much more expensive to design and make for a flatbed or film
scanner and would raise the price of such scanners probably more than the
public would be willing to send.  The Beseler 4x5 film holder that you
speack of as well as the medium format and 35mm Negatrans put out by Beseler
for moving negative strips from one frame to another while under the
enlarger without having to take the film holder out of the enlarger run
anywhere from $50 to $100 on the used market and would be much more  on the
new market.

>These Beseler holders put two rows of "teeth" marks at the edge of the
image area but they
>worked well.

Actually, if my holder is an example of all such holders, they do not have
"teeth"  and do not leave the marks you describe.  It involves a smooth
clamp down that grips the film tightly and via a set of gears moves back
away from the opposing clamp, thereby stretching the sheet of film across
the opening but not so tightly as to pull the film out of the grip of the
hold down clamps.  To keep any resulting tension from buckeling the film
holder frame itself, the film holder frame is made of heavey rigid pot metal
and has at least a 1" margin of metal bordering all the sides of the film
opening.  To utilize this sort of a design on some of the desktop film
scanners would increase their foot print significantly - look at the size of
the Imacon scanners that you refer to as compared to the the current batch
of desktop scanners as well as the costs.

-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of DaleH
Sent: Thursday, May 16, 2002 7:40 AM
To: laurie@advancenet.net
Subject: [filmscanners] Grip and Stretch film holders


I used to use a 4x5 film holder with a Beseler enlarger which gripped
two opposing edges of the film and stretched it tight to avoid
sagging and reduce buckling during exposure. These Beseler holders
put two rows of "teeth" marks at the edge of the image area but they
worked well. Why can't someone come up with a way of gripping and
stretching film in a glassless film scanner? The 35mm stock aready
has easy to grip sprockets. MF film might be a bigger technical
challenge but the results would be worth it, especially with talk of
4x5 scanners on the table. I know how Imacon "bends" film to take out
the slack, just wish there was some glassless method for flattening
film in mid range scanners.
DaleH

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