PDA

View Full Version : Paper Negative Reversal Process



Pages : [1] 2 3

aaronmichael
03-23-2011, 06:38 PM
Not sure if this is supposed to be posted in this forum but I figured a lot of pinhole photographers work with paper negatives and that's what my question is about. I want to try the reversal process with some of my 8x10 pinhole paper negatives (that I'll shoot in the future). I've read some things about how it's done but am still a little confused. Also, in my case, I'd be doing this at the lab at school so - could someone give me a quick explanation of how it's done and tell me what I need to ask the people working at the lab for when I try it out. This is just for fun so I don't need to use the best of whatever chemicals, I'd be happy with any results even if they were bad. We very well might not even have the right things at the lab to do it. Any instruction would be greatly appreciated!

Photo Engineer
03-23-2011, 06:52 PM
You will need Dektol, Sodium Hypo, Potassium Dichromate, Sulfuric Acid, Hardening fixer, and Sodium Sulfite.

Process:

Dektol 1:2 or 1:3 for 1 - 3 minutes DBI..
clear in Sodium Sulfite bath (about 20 g/L) 1 min
Wash 1 - 2 mins.
Bleach in Dichromate + Sulfuric acid (formulas all over APUG and elsewhere for this)
clear in above clear about 1 min
Wash 5 mins
Turn on the lights and FOG the paper front and back.
Dektol again but with 500 mg /l of Sodium Hypo, DBI again.
Stop
Hardening fix
Wash

This should work. There are many many alternates for the bleach and the redeveloper.

PE

aaronmichael
03-23-2011, 07:05 PM
You will need Dektol, Sodium Hypo, Potassium Dichromate, Sulfuric Acid, Hardening fixer, and Sodium Sulfite.

Process:

Dektol 1:2 or 1:3 for 1 - 3 minutes DBI..
clear in Sodium Sulfite bath (about 20 g/L) 1 min
Wash 1 - 2 mins.
Bleach in Dichromate + Sulfuric acid (formulas all over APUG and elsewhere for this)
clear in above clear about 1 min
Wash 5 mins
Turn on the lights and FOG the paper front and back.
Dektol again but with 500 mg /l of Sodium Hypo, DBI again.
Stop
Hardening fix
Wash

This should work. There are many many alternates for the bleach and the redeveloper.

PE

Thanks for the quick reply and step by step instructions. Can any of the chemicals be eliminated or are all of them required and if all of them are required do they have names besides their chemical names? I just want the greatest chance of our lab having what I need. Since it's in a class darkroom, not my personal one, can I fog the paper under the enlarger rather than turning the lights on? Wouldn't want to kick everyone out of the darkroom just to fog my paper.

Photo Engineer
03-23-2011, 10:13 PM
Your best bet is to use a prepared reversal kit.

An enlarger might be too weak in output to fog the paper correctly.

Take the paper out of the darkroom and fog it in room light.

There are dozens of methods for doing this type of process.

PE

aaronmichael
03-23-2011, 10:39 PM
Your best bet is to use a prepared reversal kit.

An enlarger might be too weak in output to fog the paper correctly.

Take the paper out of the darkroom and fog it in room light.

There are dozens of methods for doing this type of process.

PE

Thanks, appreciated.

Anyone else care to chime in?

2F/2F
03-23-2011, 11:37 PM
Hi,

FYI, you don't have to do this with your in-camera paper. You can just make a negative and use a contact printing frame to smash it face to face with another piece of paper. It is just like making a contact print or proofsheet. And you get more control of contrast that way, and can burn/dodge.

Especially since you are in a group lab, this would probably be a preferable way to go about it. At least until you set up your own darkroom...and for the reversal procedure, it literally just needs to be "A Dark Room," with some trays in it. No enlarger necessary.

aaronmichael
03-24-2011, 12:17 AM
Hi,

FYI, you don't have to do this with your in-camera paper. You can just make a negative and use a contact printing frame to smash it face to face with another piece of paper. It is just like making a contact print or proofsheet. And you get more control of contrast that way, and can burn/dodge.

Especially since you are in a group lab, this would probably be a preferable way to go about it. At least until you set up your own darkroom...and for the reversal procedure, it literally just needs to be "A Dark Room," with some trays in it. No enlarger necessary.

Well the problem is that I've made many contact prints with paper negatives and I'm just starting to get bored with it which is why I wanted to try out the reversal process for fun. Maybe I'll just have to get creative with my contact printing to keep me entertained until I personally have the proper chemicals and setting to do it.

tomalophicon
03-24-2011, 12:26 AM
There is a positive paper available from Ilford. You probably knew that already.

aaronmichael
03-24-2011, 12:36 AM
There is a positive paper available from Ilford. You probably knew that already.

If it came in a sample pack or something then I'd go for it. I just don't feel like paying over $2 a sheet for 8x10.

aaronmichael
03-24-2011, 03:45 AM
Some question about process and chemistry:

1. Does the sodium hypo = sodium hypochlorite?
2. Where can I find the potassium dichromate if we don't have it at the lab? Would Freestyle carry it?
3. Where can the sulfuric acid be found if we don't have it at the lab?
4. How long should the paper be fogged for under indoor lights before it's taken back into the darkroom?

Photo Engineer
03-24-2011, 10:56 AM
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!

PE

aaronmichael
03-24-2011, 01:59 PM
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!

PE

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.

jesterthejedi
03-11-2012, 09:34 PM
http://www.adorama.com/VBSPF.html

There is also a cheaper one but this seems like good paper.

holmburgers
03-11-2012, 10:36 PM
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.

andy_k
09-30-2012, 04:22 AM
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.

holmburgers
10-14-2012, 11:16 AM
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!

SMBooth
10-22-2012, 04:58 PM
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.

desertrat
10-23-2012, 11:38 AM
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.

Photo Engineer
10-23-2012, 11:54 AM
No! You need either Dichromate or Permanganate.

PE

maximgrew
10-23-2012, 12:00 PM
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

http://photo.net/film-and-processing-forum/00ADv3