Well, I investigated the idea that I thought would allow me to print them faster – doesn’t work sadly πŸ˜›

The idea was sensitizing the solution with methylene blue dye – Only I think I may have used a bit much as it pooled quite drastically, and frankly it cut the sensitivity away to nearly nothing, so I may be on to something with the idea of spectral sensitizing, just I have it backwards or something. *shrug*

That’s my pouring bench, my uber high tech coating method is to put about 1/6th tsp of solution in a spoon and then dump it in the middle of a clean plate… Like so (after 30 sec or so of spreading out).

I was double coating those in the hope it would make a difference – it didn’t. With a clean glass plate the solution will spread itself out by capillary action or something – over a minute or two it basically covers the plate on it’s own – this makes for a slightly thicker coat at the center, but unless you’re dopey enough to add dye to it it shouldn’t matter.

Some coated plates;

So in essence, the blue dye offers no advantage, coats really badly, slows down the print time (1/2 a day out to 2 1/2 days), and to boot, it makes a bloody awful mess when (not if) it gets spilled.

I guess it eliminates a variable – Yay me!

This is the closest that i got to a print;

It’s from a negative, so is negative, and it’s on black perspex – a substrate which, excitingly enough, I have discovered does not work at all well with this process (it coats very unevenly) – though it is good for backing coated glass plates – In the following I’ve bumped the levels and suchlike a bit.

I can make stuff out cos I know what the neg was – a view from my atillier window amusingly enough – there’s a square white sign in the foreground, some stairs about 1/3rd of the way up towards the right – and at the same level on the left a rounded window on the building facing me – very bloody hard to photograph.

So for now, I’ll go back to 1 & 2% solutions of rosin in ethyl alcohol on chemically cleaned glass plates, cos I’m reasonably sure that works.


2 thoughts on “Physautotypes…

  1. Cook the rosin down about 10 percent, grind it up and dissolve it in 95 percent alcohol (.4-6 percent) then you can pour it onto clear glass. Allow the excess to flow off the plate and while doing this blot the bottom edge while fanning the surface of the inclined plate with a hand fan ( I use a Japanese fan). If you need a second coat lightly buff the frosty surface with wadded cotton and pour a second coat fanning it as before. Expose and develop face down over a dish of odorless mineral spirits to taste. πŸ™‚ Mount with the image in contact with shiny metallic silver Mylar.

    We teach workshops in how to do this process here at George Eastman House, International Museum of Photography and Film, Rochester, NY Google photography workshops at George Eastman House

    Mark Osterman

    1. Hi Mark, thanks heaps for the tips, I really appreciate it, I’d been working from the original Niepce/Dageurre letters and from scientific papers on rosins for the most part, which was a less than entirely wonderful way of going about it, though it’s been utterly fascinating, if a little frustrating at times πŸ™‚ I especially appreciate the tip on pouring, it sounds much simpler than what I was doing.

      I have been coating the glass double sided and then printing with a black paper backing to cut down reflection (which gives a second looser print layer on the back of the plate) and then securing them in a case made from laser cut black perspex with a glass front. this gives an interesting three dimensional effect with the thickness of the glass, and the black perspex is pretty easy to work with.

      I’ve moved to Australia a few months back, which is probably a great move in terms of the intensity of the sun, but it’s seen me go somewhat inactive while i play catchup on all of the regular fronts. But I’m very interested in beginning to work especially with physautotype again, partly due to it’s accessibility, but also due to the fact that I’m beginning to find images which feel appropriate (admittedly with rather non-puritan techniques) to the media, I had to shelve my investigations towards the end of my masters program as I really had my hands full with all of the other media i was using (one can have too many strings in one’s bow).

      Specific questions; What form of rosin have you been using? I’ve been using the cake form which is used for violin strings, and what sort of scale have you worked up to? I’ve had issues with the coating, so I’ve only been up to halfplate. I’m not of the belief that bigger is better, however, not having large format camera gear in this country frees me up to use digital output methods for the negative (well, positive) production, so I’m not really limited by that at this point, and I’d like to see what they look like at a larger scale.

      Again, thanks, I really appreciate the tips πŸ™‚


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