[Alt-photo] Re: Mechanism for Platinum Enlargements

[andy schmitt]

Marek,
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
printing.
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...
Regards
Andy Schmitt

-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Marek Matusz
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
image Marek

Sent from my iPhone

> On Nov 7, 2013, at 6:41 PM, "Francesco Fragomeni" <fdfragomeni at gmail.com>
wrote:
> 
> 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
production.
>>> 
>>> 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
achieved.
>>> 
>>> 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?
>>> _______________________________________________
>>> Alt-photo-process-list | altphotolist.org
>> 
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