PDA

View Full Version : Using Platinum/Palladium for Glass Plate Negatives?



nikonfan63
3-Dec-2016, 15:55
Hello all,

Just a random question that I've been pondering lately:

Can you use platinum and/or palladium to coat glass plate negatives, instead of the usual silver? Do you know if anyone has tried this? I know platinum/palladium are used for printing but I've never heard of anyone using it for actual image capture.

Thank you!

Vaughn
3-Dec-2016, 16:03
Super long exposures, I assume, since one needs the far blue and UV light to make the exposure. There is a cyanotype process that is speedy enough for in-camera use, but I have not heard of anything on a pt/pd process that would be fast enough in-camera.

It is possible to expose onto glass coated with pt/pd instead of coated paper.

Greg
3-Dec-2016, 16:57
One of my students tried to make Platinum/Palladium paper negatives using coated paper loaded into normal sheet film holders. It was a bright sunny day and he told me he made "very long exposures". No image on the papers.

Vaughn
3-Dec-2016, 20:31
A simple (one piece of glass?) lens, no coatings, wide open might help some. Glass just absorbs a lot of UV!

domaz
5-Dec-2016, 13:06
No idea if this would work with Platinum but I've been meaning to try this with carbon printing for fun. Carbon tissue is a little bit faster than Platinum generally I believe so might have a higher chance of working. The basic idea would be:
1. Make some carbon glop and coat on paper or x-ray film as you would normally, to make carbon tissue.
2. Sensitive it in the normal fashion and stick it in your film holder.
3. Transfer the exposed tissue onto a glass plate or film base. Gelatin "likes" glass and it's simple to transfer onto without doing anything but a minor cleaning.

If it did work I would consider using some kind of hardener as carbon prints transferred onto glass tends to be very very delicate.

The end result would be a glass negative if everything went well.

Vaughn
5-Dec-2016, 14:13
I think about all that UV light streaming from my 1000 watt lamp, less than a foot from the carbon tissue for an hour exposure. Then I think about the small amount of UV trying to make its way thru a bunch of glass and through a tiny little hole (lens/aperture). We're are talking all-day exposures, with spontaneous exposure within the tissue (non-image making) happening due to the length of time (multiple day exposures probably would not work).

Still would be fun to try! Best at high attitudes where there is more UV! High pigment load and a high sensitizer strength, too, will help.

Andrew O'Neill
5-Dec-2016, 14:19
So, you make a platinum/palladium negative... then what? Or is the negative an end in itself?

Vaughn
5-Dec-2016, 16:51
One needs to produce an in-camera pt/pt negative with enough contrast to use it to make a pt/pd print! Thus earning the title of Dr. Platinum!

jprofita
5-Dec-2016, 18:31
I have been "successful" exposing ferric oxalate coated paper with meniscus and projector lenses for 1 1/2 to 2 hours in full sun. Does the Pt/Pd slow the emulsion substantially?

Vaughn
5-Dec-2016, 18:50
I have not compared the printing times of the standard cyanotype vs a pt/pd print, but I suppose they are of the same magnitude. Certainly slower than what you are getting with just the ferric oxalate.

Randy Moe
5-Dec-2016, 21:23
158330

Appears they are shooting PT