[alt-photo] Re: Dichromated Gelatin Formula

[Francesco Fragomeni]

Great questions Gordon! 

Also, during the time Woodbury was making these, variations of the process were devised that eliminates the need for the lead plate and the extreme pressure needed to make them. To my knowledge the products of these methods are indistinguishable from lead plate Woodburytypes.

Francesco

Sent from my iPhone

On Sep 23, 2012, at 3:27 PM, Gordon Holtslander <gjh at shaw.ca> wrote:

> Could using different more malleable metal than lead support an easier way of making Woodburytypes?  Aluminum is more malleable.  Could a stack of aluminium foil work?
> 
> Was aluminium common when woodburytypes were made?
> 
> Gord
> 
> etienne garbaux <photographeur at nerdshack.com> wrote:
> 
> I wrote:
> 
>> I seem to recall that one or more of the other old salts (Wall?  Clerc?)
>> also gave Woodburytype formulas, but do not recall which one(s).
> 
> I think the other reference I was remembering was in Crawford's 
> Keepers of Light.  He gives a nice historical description, but no 
> workable process information.
> 
> The motherlode for potential Woodburytypists is Leon Vidal's Traite 
> Pratique de Photoglyptie (Gauthier-Villars, 1881).  ("Photoglyptie" 
> is the French name for the process.)  Eder translated it into German 
> as Die Photoglyptie oder der Woodburydruck (Knapp, 1897).  I have 
> both around here somewhere, but am not finding them at the moment.
> 
> I believe that Woodbury also had some English patents on the process 
> that might be worth looking at.  They would probably date to the 
> early 1860s through the mid-1870s.  (If you find the patents, please 
> post links.)
> 
> Now the bad news:  The magic of the process, and what gave 
> Woodburytypes their ethereal look, was the immense pressure used to 
> make the lead molds.  Because of that, no modern casting process has 
> even the slightest chance of making images that look like 
> Woodburytypes.  (Woodburytypes have relief, like a carbon print.  The 
> shadows are very glossy and well-defined, while the highlights are 
> subdued and matte.  Some of the fine details in the highlights are 
> softened, which gives an effect not unlike a good soft-focus portrait 
> lens.  A very handsome combination, IMO.)  So, if your goal is to 
> achieve the look of a Woodburytype, you will need to find a big 
> honking hydraulic press you can use.  You'll need over 500 kg per 
> square cm, so even modest sized prints require a press capable of 
> over 100,000 kg of force (over 100 American tons) -- like this one: 
> <http://www.phoenixhydraulic.com/Presses/HFrameShopPresses/150200TonHFramePresses/tabid/197/Default.aspx>. 
> (That is a general shop press, so it opens way, way more than you 
> would need -- but that's the kind of press you would be most likely 
> to find available to use.  Lots of small and mid-sized industrial 
> companies have them for working with metal.)
> 
> Best regards,
> 
> etienne
> 
> 
> 
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo