Silver emulsion reversal effect on dry plate glass?

I want to put a plate of glass on a black background, like an ambrotype, to result in a positive image. This exposure will be using a pinhole and I'm using silver emulsion but am open to alternatives. The exposure could be up to 2 hours and be okay for my workflow. It's a landscape of a city during the day. So far I've used liquid light and AG+ on paper with this design and 40 minute - 1 hour exposures work fine. I boost contrast by adding Dektol to the emulsion 1:10 but this image is quite low contrast so I imagine it'll continue to be a problem in the future.

Here are my caveats

• I can't use ambrotype process or wetplate anything because it's too slow and I need to hike up a mountain for an hour before I can make the exposure.
• I live in Korea, but so far can't get Rockland's tintype kit sent here any which way I know. I have never tried this process but would like to. It would be ideal, right? I was just in Berlin and yesterday on the way back lost some other chemicals in Chinese customs just because they didn't like it.
• If you're wondering, I want it to be glass because of aesthetics. There are also other things I'd like to try but am trying to be concise here. I'm really inspired by Borut Peterlin's youtube channel on other processes.

I've used Harmon Kardon direct positive paper, considered lith printing, but I want to use glass if there is a way.

Is there a post-development bleach process that I haven't discovered? Is there a development process I could create to use with silver emulsion? We have lots of chemicals available in Korea but I've never tried making my own chemistry. I'd be happy to if there might be a way.

I use liquid light and AG+ for my work currently but am considering Foma based on reviews here. I have no problems getting these in the mail from B&H.

I hope this is clear, thanks for your advice!

There's two ways that I can think of. I've done both. 3rd way I havent done. I'm sure others will suggest more.

1). Use glass plate as negative, develop as normal then, when mounted in front of black paper, shine light on the plate at an incident angle... from almost directly above or directly below. Some of the light will reflect off the silver grain and out towards the viewer. The effect is faint but doable.

2). Expose as normal and then contact print onto a second glass plate as you would paper. Mount the second plate in front of a light box, window, etc

3). Read this post: https://www.photrio.com/forum/index.php?threads/reversal-processing-of-black-white-paper.44354/

hi psyncro
sorry to hear customs isn't being friendly with your chemistry !
you can make your original image on film
and contact print or enlarge it on your glass, that would be the easiest approach ..
if it has to be a super slow exposure for the effect/type of image you want to make
you can put a neutral density fiilter infront of your pinhole to slow it down.
if you can get dektol, sodium carbonate, ammonium thiocyanate and fixer
you can make your own tintype reversal developer
donF published a tested formula in this thread
Rockland Colloid - Should I bother?
like the rockland developer, it is finicky.
jill enfield + steve anchell publish reversal formulas in their books too, if you can get them ..
they are also tested.
as a different approach, you can let a little light to strike the image, which will solarize it,
when you develop it normally in regular old developer, it won't give you the same reversal effect but ...
it will do something similar.

have you gotten the hang of coating glass plates yet?
aside from making sure water "sheets" off the glass before you coat it with emulsion,
two other tricks are putting the plate on a flat and extremely cold surface
so it sticks to the plate, and using hardener in your fixer. i can't tell you how many plates
( small ones like 2x3 and big ones between 11x14 and 16x20 )
i coated well, and made perfect exposures on, only to watch the emulsion lift completely off the plate ...
and wash down the drain because i didn't know how to chill the plate.

have fun with your project !
john

This is such an amazing amount of information from you guys and I am so appreciative. Really it is amazing every day to learn how little I know. I am going to keep reading through your replies and links and then let you know how I proceed with the work. Using incidental light to glow the silver is something I honestly never thought of that could be really beautiful to display. I love to play with light in the exhibition room. I will have to try everything now I think, but I need my result by the end of the year because my visa will finish. I am really excited to share with you my project too once I am making progress.

I thought that I will try using gelatin to sub the liquid light to the glass plate but yes, I have never made a glass plate before. I have had the emulsion lift off of even glossy paper, even, but I kind of liked the effect when it didn't totally disintegrate. I like how the emulsion folds over and creates creases that dry flat. I might be upset with this on a glass plate though certainly. I'm surprised that the emulsion is quite durable and when it hits the hardening fixer it's amazing how it'll form up to anything. I've even floated it off one paper and onto another, and could explain how to do it were there ever any application for such a jilted process.

To be honest, this project started 2 years ago with resin-coated paper, then I experimented with cyanotype (19 hour exposure excluding nighttime that kind of worked), liquid light and direct positive from Harmon Kardon, then back to liquid light. The concept of my work would work best made with a positive as the original plate ideal but yeah, a contact print with the same size glass I think would not be cheating too much, and create a nice result. I will test.

I work as an assistant during the day and my gracious boss lets me use his studio for my work, but I decided recently to convert my small apartment into a test camera obscura / darkroom to get my workflow down and have total control. It really takes 3-4 hours just to get up the mountain and set up the camera even before I can make an exposure, so I want to be proficient and have a static environment in which to work in.

Right now I don't know whether to worry about the hair from my cat more or proximity to darkroom chemicals. She's a curious creature herself. I might ask her to stay with a friend for the next few months.

Thanks again so much.

julian

I decided I'll keep updating here to keep my experiences together into one thread. I hope this ends up useful / interesting to someone

Updates:

• I decided to not do the ammonium thiocyanate reversal method because I don't have time to sufficiently test it. Instead, I'll try Nodda Duma's 2nd idea above. Not sure I like the feel of opalotypes though. Will experiment.
• but I will try DonF's method later (linked here) because I found someone I can get ammonium thiocyanate from here.
• My apartment is now completely turned into a darkroom, and my fridge an ideal safebox to finish drying during the day (so my cat doesn't go insane in the dark).
• I'm getting better at coating, but think I need a thinner solution, especially using the glass rod. I'm heating the plate on a hot pad but it's just too thick still.
• I found knox gelatin and used it, but liquid light was too thin I believe. Trying non-subbed glass tomorrow. I haven't used my Ag+ yet as I'm waiting to get better at coating.

Questions:

• Is there a substitute for thinning the emulsion other than photoflo? I can't get it right now do to long lunar thanksgiving holidays. An alcohol of some kind, perhaps?
• In the past I always added 1 unit of Dektol to 10 units of Liquid Light to boost contrast. This time, I'm getting some darkening in the mixture before coating. It turns slightly grey and pours on grey. Any idea why this might be?
• Would you expect to see the included image, if it is an exposed negative of liquid light with 1:10 dektol on a paper with glossy silveryish sizing with normal dektol and Kodak hardening fixer processing? I can't quite get what's going on here. I took a normal photo so you can see what the surface looks like to the eye. This is 2 years old.

I'll have comparison photos of what adding dektol to the emulsion does up in a few days.