[alt-photo] Re: Photo Booth Info

[Richard Knoppow]

     I think the sepia color is from development in a 
sulphide bath.  Reversal paper or film can have a second or 
reversal development in a bath similar to the re-developer 
of a sepia toner.  The advantage of this is that the 
redeveloped images do not need to be fixed again since all 
halide remaining in the emulsion is converted to silver 
sulphide and is stable.
     Its possible that more than one process was used. 
There are direct-reversal materials that use pre-fogged 
emulsion.  As you know a very heavy overexposure will drive 
most emulsions into a reversal zone.  It is possible to make 
an emulsion where all exposure results in such reversal.  I 
no longer remember if a special process is necessary to 
develop it but I believe one advantage was a simpler process 
than normal reversal.  Kodak and others made such materials 
for producing duplicate negatives directly from an original 
thus saving a generation.  The conditions in a photo-booth 
would have been favorable since there would have been good 
control and consistency of the exposure.
     POP is a printing method requiring a negative.  The 
familiar POP paper works by having an emulsion with enough 
excess silver in it to produce photolytic silver under the 
influence of very strong light. If not given further 
processing the image is not permanent since further exposure 
to light will eventually fog the entire surface. This 
property accounts for the use of POP for approval proofs. I 
was told (don't know if its true) that Kodak put something 
in their POP to insure it would fog over time even if in the 
dark.  Certainly overage Kodak POP is always completely 
fogged even if in un-opened packages.
     The image can not be fixed with a normal fixer since it 
is composed of extremely fine silver particles which have 
little resistance to bleaching by the usual hypo.  The usual 
process is to tone the silver with gold or platinum and then 
fix it. The toner and fixer can be combined in one bath. The 
toner also changes the image color from a sort of maroon to 
neutral or blue-black. I think platinum can also produce a 
sort of brown-black and intensifies the print.  Salt prints 
and POP made with albumin in place of gelatin work similarly 
but are nearly always processed in a toner and fixer.
     I suspect one of the older books on photographic 
methods has something definite on the process used in 
photobooths.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com
----- Original Message ----- 
From: "Jack Fulton" <jefulton1 at comcast.net>
To: <alt-photo-process-list at lists.altphotolist.org>
Sent: Tuesday, September 11, 2012 9:07 AM
Subject: [alt-photo] Photo Booth Info


> >From Ryuji
>> I have a friend (also a neighbor and cinematographer) who 
>> tells me a story of a
>> photobooth setup producing what looks like a b&w contact 
>> print of a strip of 4
>> pictures taken on film in 2.5 minutes. This must be from 
>> 60s or 70s. Does anyone
>> have information about how these devices were generally 
>> designed, in terms of
>> optics, lighting, film stock, processing, etc? I'm not 
>> sure if this is exposed on direct
>> positive paper stock directly with intense flash, or is 
>> it a negative-positive process.
>> If latter, it'd take 2.5 min just to develop pictorial 
>> film in D-19 or DK-50 or whatever.
>> Does this use  an instant film stock?
>
> Reply by Richard Knoppow
>    I am pretty sure these used direct-positive paper and 
> probably worked about like
> the street photographers cameras. The ones I remember from 
> when I was a kid
> delivered sepia images which may be a clue as to the 
> process.  They were  found in
> many places.
>
> Like Richard, I'm positive it is direct-positive paper. 
> There is one in the Marc Jacobs
> store on Melrose in Los Angeles and somewhere around here 
> the photos are still okay
> after a couple of years.
> I wouldn't be surprised if the sepia ones Richards 
> mentions were on POP for that is how
> pro photographers would deliver 'proofs' to families in 
> the 40's and 50's
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