I don't understand what just happened

[dpurdy]

So cleaning and organizing and sorting through old boxes of paper and running tests to see how viable they are for platinum printing, I ran across a box of silver gel paper made by Kodak in the 1940s. The box says "AD TYPE A-1". It is single weight 11x14 paper with a beautiful sheen on the emulsion side. I've kept for many years thinking that the paper side might be good as a platinum printing base. Today I decided I should run a test and see. I have had it for over 40 years and never considered it viable as a silver printing paper. I have opened it in the light multiple times and thumbed through it and never thought I should keep it in the dark. I researched it and I think it is from 1949. Way too old to be viable.

So I coated the back of one of the sheets with pure palladium, and then dried it with a hair dryer, and then humidified it with a pan of hot water and then put a negative on it and exposed for 6 minutes in ultra violet light and it came out with a beautifully smooth image. But when I turned it over in a tray of water there was the image beautifully exposed on the emulsion side. The image was mirror image and it was a positive image rather than negative. I am flabbergasted. I don't know how to account for that. Now I have to do some testing to see if a platinum developed image can be fixed in silver fixer and try to understand what I am looking at.

 

[Kino]

Truly wild...

 

[Don_ih]

Ad-Type is the Azo emulsion coated on thin paper.

That's a secret, by the way. Shhhhhh.

 

[Romanko]

You must have solarized the original paper. 6 minutes under bright UV could give sufficient exposure. Could you try to run a step-wedge test under UV light to check if there is some residual sensitivity in that old paper?

Just to clarify, you didn't fix the paper before using the back side of it for palladium print, did you?

 

[koraks]

But when I turned it over in a tray of water there was the image beautifully exposed on the emulsion side. The image was mirror image and it was a positive image rather than negative. I am flabbergasted. I don't know how to account for that.

When printing something like Pt, you're effectively turning a water-soluble platinum salt into metallic platinum (and some other stuff that drifts away). Apparently, the water-soluble platinum-based sensitizer can reduce silver halide (silver chloride in this case) into metallic silver. I'd have to sit down and think about which compounds and mechanisms would be involved, but platinum's nature as a strong catalyst may have something to do with it, somewhere. Note that the platinotype developer might also very well play a role, for instance as electron donor. Note that the platinum sensitizer is water-soluble, so it can migrate through the paper base also when the print is in the developer bath; the printed out metallic platinum image is immobile and thus would not affect the opposite side of the paper.

Maybe @fgorga could comment; this seems like something he might know, or readily be able to figure out.

 

[dpurdy]

What I don't understand most is why, if the silver emulsion was still viable, didn't it turn black. It must be that the AD type 1 paper is sensitive to ultra violet far more than regular spectrum light. I had made no attempt for years to keep that paper in the dark and in coating and printing the backside, and left sitting on a table for about an hour waiting for me in only slightly dimmed light.
So now of course I have to try exposing the emulsion side and processing it in regular silver gelatin developer. I am not sure I want silver and gelatin in my platinum developer.

 

[koraks]

What I don't understand most is why, if the silver emulsion was still viable, didn't it turn black.

You're assuming the silver density correlates to exposure to light. That is not necessarily the case. It may be, but not per se.

 

[Lachlan Young]

Look up Edith Weyde & how she discovered Diffusion Transfer Reversal. Polaroid 'borrowed' it wholesale.

 

[Certain Exposures]

So cleaning and organizing and sorting through old boxes of paper and running tests to see how viable they are for platinum printing, I ran across a box of silver gel paper made by Kodak in the 1940s. The box says "AD TYPE A-1". It is single weight 11x14 paper with a beautiful sheen on the emulsion side. I've kept for many years thinking that the paper side might be good as a platinum printing base. Today I decided I should run a test and see. I have had it for over 40 years and never considered it viable as a silver printing paper. I have opened it in the light multiple times and thumbed through it and never thought I should keep it in the dark. I researched it and I think it is from 1949. Way too old to be viable.

So I coated the back of one of the sheets with pure palladium, and then dried it with a hair dryer, and then humidified it with a pan of hot water and then put a negative on it and exposed for 6 minutes in ultra violet light and it came out with a beautifully smooth image. But when I turned it over in a tray of water there was the image beautifully exposed on the emulsion side. The image was mirror image and it was a positive image rather than negative. I am flabbergasted. I don't know how to account for that. Now I have to do some testing to see if a platinum developed image can be fixed in silver fixer and try to understand what I am looking at.

Could you please share a picture of it with us?

 

[dpurdy]

Could you please share a picture of it with us?

Yes I could but I don't have a cell phone so I will have to get a camera out for it.
In the meantime I have done a second experiment this morning. I sandwiched the negative on the emulsion side and exposed it under the ultraviolet lights and got a purple image that has a pretty good range of tones and the part that should be black is very dark purple. However when I put it in potassium Oxalate developer it didn't change at all. So it is like any other black and white paper that if you lay something on it in the dark and then turn on the lights after a short while the uncovered areas get dark and the covered areas stay light. So I have to, of course, next try processing this paper in regular paper developer. I am still amazed that it is this capable of printing and showing contrast when this paper is literally over 70 years old and I have done nothing to protect from light or age even leaving the lid off the box for long periods of time.

 

[cliveh]

Yes I could but I don't have a cell phone so I will have to get a camera out for it.
In the meantime I have done a second experiment this morning. I sandwiched the negative on the emulsion side and exposed it under the ultraviolet lights and got a purple image that has a pretty good range of tones and the part that should be black is very dark purple. However when I put it in potassium Oxalate developer it didn't change at all. So it is like any other black and white paper that if you lay something on it in the dark and then turn on the lights after a short while the uncovered areas get dark and the covered areas stay light. So I have to, of course, next try processing this paper in regular paper developer. I am still amazed that it is this capable of printing and showing contrast when this paper is literally over 70 years old and I have done nothing to protect from light or age even leaving the lid off the box for long periods of time.

But if the paper is in a stack, only the upper sheets may be fogged to a noticeable extent.

 

[koraks]

However when I put it in potassium Oxalate developer it didn't change at all.

So maybe the whole thought of the platinum doing something wasn't so far-fetched after all. You could design some additional experiments to figure out:
* whether it's a side-effect of the self-masking process in which a printed out image appears on the backside of the AZO paper, thus blocking light that gets to the original emulsion, resulting in a positive image
* or the Pt sensitizer indeed acting as a reducer and/or catalyst in some way, resulting in a positive 'transfer' image
I have a pretty good feeling it's not the first, because there's still the negative in the stack as well... Besides, consider the hint given by @Lachlan Young .

 

[Lachlan Young]

It's quite probable that an accidental Satista print was made (with elements of diffusion transfer reversal) - or something effectively chemically-speaking rather close.

And Ad-Type paper has no Baryta layer (it was for airmail etc - folding without cracking) separating emulsion from base.

Nothing new or unusual here really.

Edited To Add: there's possibly an experiment to be made with the paper exposed in camera, silver gelatin side to lens - a sort of Satistaroid if you will.

 

[Don_ih]

Ad-Type is very slow - like Azo and old Velox. So, putting it in a camera would require a very long exposure time.

I have two boxes of 8.5x11 ad-type. None of it is fogged whatsoever and is around 60 years old or so.

I am still amazed that it is this capable of printing and showing contrast when this paper is literally over 70 years old and I have done nothing to protect from light or age even leaving the lid off the box for long periods of time.

It will happily lumen print, as you discovered. But, if not protected from light, the sheets will turn completely black in regular paper developer.

 

[Lachlan Young]

So, putting it in a camera would require a very long exposure time

Yes, but considerably more achievable than trying to expose pl/pt in camera...

It was more about the proof of principle - there are other non-baryta layer papers of enlarging speed out there - you could possibly even make it work with Art 300.

 

[Don_ih]

considerably more achievable than trying to expose pl/pt in camera.

Maybe a little.

I recently contact printed an 8x10 onto Ad-Type. The negative that required 12 seconds with Ilford MGIV FB required 3 minutes with Ad Type (same light source that I opened up a stop from the Ilford exposure). I think it would be close to a day in a camera. I know nothing about platinum, though.