From: Rod Fleming (rodfleming@sol.co.uk)
Date: 08/30/00-06:09:54 PM Z
Hi Bob
I think you are talking about selective latent image management techniques,
shortened to SLIMT,or the Sterry technique . With reference to prints, this
allows, in effect, for the contrast range of the paper to be modified- in
other words graded paper can be used as a sort of multigrade.
The original Sterry method used a dichromate bleach but this was revised by
the photographer David Kachel who developed a new version which uses very
dilute potassium ferricyanide (which is used in Farmer's Reducer etc) for a
period of between 1-3 minutes between exposure and development. The real
advantage of the technique is that it is _selective and proportional_. It
bleaches the most exposed areas the most.
so, unlike Farmer's on a developed image, where the bleach acts as a
"cutting" bleack and reduces _density_, the latent image bleach acts as a
proportional bleach and reduces _contrast_.
Thus an image with a very high contrast- say a sunlit scene- can be
controlled and printed on a G3 or 4 paper - the beauty being that if the neg
was printed on a G1, which might be the natural choice, there is a good
chance that the highlight and/or shadow areas will become "muddy" because we
have used a soft paper to hold the range of the neg. Using the Sterry method
we can expose this neg on G3 or4, and then bleach back the shadows, BUT
because the print is still on a hard paper, the tonal range within the
highlight and shadow areas retain their "sparkle". It works, too.
You can do a similar thing with masks but the Sterry method is a lot
simpler. And you can also do a similar thing with split-grade printing on
variable contrast paper, but then a lot of very good papers don't come in
VC.
It's a useful tool, and everybody has Pot Ferri in the cupboard. Don't they?
SLIMTs can also be used for zonal expansion and contractionin film
development.
Here are links to pages which explain it better- it's very late here!
http://www.unblinkingeye.com/Articles/LatentImageBleach/latentimagebleach.ht
ml#Kachel
http://www.cyber-wire.com/dkphoto/cont_pt3.htm
The second link is to David Kachel's site, but that link seems to be dead
right now- if you want I can send you more info direct. Just ask.
Rod
----- Original Message -----
From: "Bob Kiss" <bobkiss@caribsurf.com>
To: "ALT PHO PROC." <alt-photo-process-l@usask.ca>
Sent: Wednesday, August 30, 2000 9:29 PM
Subject: PRE DEVELOPMENT BLEACHING
> DEAR LIST,
> I read something about "pre development bleaching" in, I think,
> VIEWCAMERA. I have been around photography for three decades and this is
a
> first for me. Does anyone know to what this refers?
> CHEERS!
> BOB KISS
>
>
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