[Alt-photo] Re: Mechanism for Platinum Enlargements
aschmitt at aandy.org
Sat Nov 9 14:16:51 UTC 2013
As someone else mentioned (sorry, lost reference), the "normal" UV LED's on
the market today are a little long in the wavelength produced for good Pt
Back when I was putting together a portable printer, that was mentioned to
me contact the manufacturer of the LEDS & was told it would be a special run
to dope for that wavelength & would be expensive...
Might be able to get a bunch of us together & split up the cost of doing
that, especially if we could use the larger ones...
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Sent: Thursday, November 07, 2013 10:30 PM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [Alt-photo] Re: Mechanism for Platinum Enlargements
Maybe I could try a bank of uv led's as a diffused light source. I tried a
house led light to print cyanotype once. It was a long exposure but I got an
Sent from my iPhone
> On Nov 7, 2013, at 6:41 PM, "Francesco Fragomeni" <fdfragomeni at gmail.com>
> Don and Peter,
> Thanks for chiming in! Sorry for the delay in response. The work week
> has been insane. Anyway, the mirror idea sounds interesting. As does
> the idea about trying to find one of the Durst units. From what I
> understand the Azo enlarger was really just a Durst enlarger with the
> high powered 5kw head. I wonder how difficult it would be to get a
> hold of one of those heads. I'm also curious what the power
> requirement would be. I live in NYC so running a dedicated power source
isn't really not a possibility.
> I've also seen mentioned a number of times that people have had
> success enlarging on Azo (and feasibly pt/pl) using a regular color
> head. I'm assuming that their making use of a blue setting. It's
> strange, I've seen this mentioned but no one really seems to describe
> it in detail at all. I also have an actinic cold light back in phoenix
> which could yield a similar result. I'm unsure when Id be back there an
able to test this.
> Another question that comes up is the difference in negatives that
> would be required. I'm used to working with a denser and contrastier
> neg for contact printing pt/pl. I wonder how this would change when
> projection becomes a part of the equation. Ideas here?
> My darkroom in NYC is small and set up for contact printing so I have
> no enlarger. Maybe I'll have that cold light shipped out and rig an
> enlarger out of a spare view camera to see what I can get to work.
> Any more thoughts or ideas on this topic?
> On Tue, Nov 5, 2013 at 11:02 PM, Peter Friedrichsen <
> pfriedrichsen at sympatico.ca> wrote:
>> The ferric oxalate light sensitivity is still very good up to about
>> 520nm (throughout the blue light range) so maybe the Durst Azo unit,
>> which I see uses quartz halogen, could do the job. Perhaps you could find
one to test.
>> Peter Friedrichsen
>> At 12:40 PM 05/11/2013, you wrote:
>>> Hi All,
>>> I may have asking something along these lines a long while back but
>>> I'm unsure. There also may have been a bit of conversations around
>>> this on-list in the past. Anyway, I've always been fascinated with
>>> the old methods for making Platinum enlargements and I'm curious if
>>> anyone knows any of the numbers (exposure times) or knows of anyone
>>> who's working (albeit slowly) with anything like this now.
>>> Despite common belief, making platinum prints through an enlarger is
>>> indeed possible and there is a long history of this. As a quick
>>> recap, the most common method was through the use of a solar
>>> enlarger attached to a heliostat. The solar enlarger was essentially
>>> the same as a modern enlarger, most commonly using condenser lenses
>>> but there is documentation discussing diffusion solar enlargers as
>>> well, and lenses that were good at passing UV light. The heliostat
>>> was a mechanism that allowed the enlarger to track the movement of
>>> the sun subsequently keeping the light source centered and focused
>>> throughout the printing.
>>> Much later Durst made a UV enlarger for Azo and supposedly had one
>>> in development for platinum printing but it never made it into
>>> Anyway, I've heard whisperings of people who's made platinum
>>> enlargements essentially in conventional enlargers after replacing
>>> the lens with an older lens that'll pass uv light (modern lenses
>>> tend to block uv) but I can't really find any documentation of this.
>>> What I've heard is that the super powered lamps as used in the Durst
>>> UV enlarger (5kw and requiring serious cooling) are not actually
>>> necessary if you're ok with loooong exposure times (into hours). The
>>> Durst was supposedly designed to make these exposures both possible
>>> and relatively quick. I personally wouldn't care if the exposure
>>> times were very long if this is something that could actually be
>>> Does anyone have any information/experience with this? Any idea of
>>> how long exposure times would actually be if using a uv bulb or
>>> mercury bulb in a diffusion or condenser enlarger?
>>> Lets try to keep this on topic. This isn't intended as an opening
>>> for recommendations to contact print or make enlarged negatives.
>>> This topic isn't concerned with any alternatives. We're all aware
>>> that platinum prints are conventionally made using contact printing.
>>> We also know about making enlarged negs. No need to touch on any of
>>> that here. This is about the feasibility, practicality, and
>>> possibility of making a platinum enlargement via an enlarger set up
>>> to utilize uv light. We're also not tied to attempting to attain
>>> short exposure times here. Long is fine. I'm interested in tapping
>>> into the creative thinking of those on-list so lets try to limit the
>>> "thats impossible" talk. We already know that platinum enlargements
>>> are possible. Thoughts?
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