Sodium Hypo = Sodium Thiosulfate
Chemicals can be purchased from many companies. I use the Photographers Formulary in Montana, and APUG sponsor.
Use Battery Acid. It is 37% Sulfuric Acid and can be purchased at any auto store. Use gloves, goggles and an apron when handling the stuff and when handling and using the bleach.
You can do the final development in total room light, but I would use 1 minute room light exposure to each side if you go back into the darkroom.
AAron, are you sure you want to mess with the chemicals? You can buy a kit for this!
Hahah - I just talked to the people working at our lab and they gave me a big warning about working with these chemicals and other chemicals. I think I'm just going to have to stick to contact printing for now :( Either that or buy some direct positive paper or a reversal kit.
Originally Posted by Photo Engineer
There is also a cheaper one but this seems like good paper.
If you are careful and recognize how to work with the chemicals, there's no reason that you should be afraid to handle them (or let others suggest it's frightful).
The potassium dichromate is the only chemical that probably isn't in a normally stocked darkroom. I've heard that some kind of Kodak Tray Cleaner will work, as it's basically an ideal bleach of sulfuric acid & potassium dichromate.
Hypo clearing agent is sodium sulfite + a pinch of sodium bisulfite; I don't see why that wouldn't work for the clearing bath.
This thread inspired me a little to try making reversal photographs straight out of the camera.
However, my approach has been to employ the Sabbatier effect onto a contrasty and medium dense paper negative.
This results in a positive with a good range of tones and fair crispness, but it definitely constrains overall contrast.
I definitely haven't mastered this technique at all, but I have made a few nice looking images fooling around.
This is a self portrait that I reversed, scanned, and photoshopped a little to improve the contrast range for better computer screen viewing.
I have attained fairly normal (say a 4 stop range) level of contrast on more recent experiments, but the pictures themselves don't look as nice.
This was on some highly expired Ilfospeed Grade 3 RC, in 6x6 format. I find better results come using full strength developer, and a flash to reverse the negative.
andy, this sounds like a really fascinating method. A unique & intriguing approach!
Are you utilizing an exposure at a certain point in the development, or is it some kind of pre/post-exposure flash?
It's remarkable to me that such a good positive can be got by simply exploiting exposure at the right time... whoa!
A friend had a different approach to this and we tried it out last night. It really using the basis of a lith article by Ed Buffaloe in blinking eye. http://unblinkingeye.com/Articles/NbyR/nbyr.html
A sheet of paper (MG RC)was exposed in camera for twice the metered exposure (in testing it was found to get the best end result), then under a enlarger set to about 700mm high and lens stopped down to f22 we preflashed the paper for 6-8 sec. Developed , Stop, lights on, Bleach, Wash, Clear, redeveloped in same developer, wash, we then fixed and washed again get to clear the slimy feel. End result is pretty good. That's the basics anyway, we need to do some more testing using some originals which have been exposed the same to determine what different preflash times do to the contrast.
Can a reversal bleach be made with potassium ferricyanide? I have a good deal of this, and prefer to save my small supply of potassium dichromate for other things, if I can.
No! You need either Dichromate or Permanganate.
how about this for colour reversal? might be a little complicated but an interesting read either way I think all you would need is RA-4 paper which is cheap (and cut to film holder size) a RA-4 kit and any BW developer