[Alt-photo] Re: Mechanism for Platinum Enlargements

[Marek Matusz]

Andy

I was not interested in building a light source like that. Just mentioned the possibility. Exposures longer then 5-10 min are unbearable for me

Marek

Sent from my iPhone

> On Nov 9, 2013, at 8:17 AM, "andy schmitt" <aschmitt at aandy.org> wrote:
> 
> 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?
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