Rodinal, its true story and formula.

Film Photography & Darkroom discussion

Moderator: Keith Tapscott.

Keith Tapscott.
Posts: 506
Joined: Tue Jan 17, 2006 8:58 am
Location: Plymouth, England.

Re: Rodinal, its true story and formula.

Postby Keith Tapscott. » Fri Aug 30, 2013 3:03 am

For those who are interested in making their own Rodinal type developer for personal curiosity, here is a simplified formula designed by Patrick Gainer.

http://www.apug.org/forums/viewpost.php?p=398138


Jim Appleyard
Posts: 69
Joined: Sun Mar 25, 2007 4:33 pm

Re: Rodinal, its true story and formula.

Postby Jim Appleyard » Sun Sep 01, 2013 4:01 pm

Thank you, Keith. I enjoy reading about Rodinal.

Ornello
Posts: 833
Joined: Thu Jan 19, 2006 9:49 am

Re: Rodinal, its true story and formula.

Postby Ornello » Tue Sep 03, 2013 10:23 am

Rodinal is the Tim Tebow of developers.

Everybody thinks it's better than than it is, and won't stop talking about it.

LOL

KennyE
Posts: 98
Joined: Thu May 23, 2013 6:49 am
Location: Waterford, Michigan USA

Re: Rodinal, its true story and formula.

Postby KennyE » Wed Nov 27, 2013 4:36 pm

Ornello is correct, that people think that Rodinal is better than it exactly is. That is because it is.

I was doing some testing of a few old developers in my lab, that I was thinking about trashing. So I pulled out my listing on these samples and began to look at them closely.

Pyro and Pyrocat will not last long in a sodium sulfite and sodium carbonate solution. So I toss them out because they were dead. And if you use sodium hydroxides in them they will die even faster.

But what if we did this.

1oz of Rodinal

20ml of Pyro, mixed 10 grams into 2 oz of boiled water

10ml of Borax mixed 10grams into 2 oz of boiled water

diluted 1:80 developed 10 minutes in a tray from my 6 X 9 Speed Graphic. And it came out bitchin.

Because the Rodinal had the p-aminphenol HCI, sulfite, and hydroxide, I added the pyro, and the borax. So basically I made RPK

R= Rodinal
P= Pyro
K= Kodalk..., by adding the borax

Well I am tired now, so I will take a nap, and do some more testing after turkey day.

Thank You

KennyE
Last edited by KennyE on Wed Dec 18, 2013 10:11 am, edited 1 time in total.

Keith Tapscott.
Posts: 506
Joined: Tue Jan 17, 2006 8:58 am
Location: Plymouth, England.

Re: Rodinal, its true story and formula.

Postby Keith Tapscott. » Thu Nov 28, 2013 8:34 am

KennyE wrote: Pyro and Pyrocat will not last long in a sodium sulfite and sodium carbonate solution. So I toss them out because they were dead. And if you use sodium hydroxides in them they will die even faster.



KennyE
Pyro is not stable when stored in alkaline conditions. Why would someone use sulphite or carbonate solutions for Pyro?

KennyE
Posts: 98
Joined: Thu May 23, 2013 6:49 am
Location: Waterford, Michigan USA

Re: Rodinal, its true story and formula.

Postby KennyE » Fri Nov 29, 2013 9:39 am

Keith, hello and how are you?

After re-reading my post, I discovered where I had made it confusing to understand my actions and ideas.

What I did was to take 1 oz. of my home brewed Rodinal and diluted it 1:80, and to it, I added the concentrated amounts of Pyro and Borax. What I had was an A, B, C formula of Rodinal, Pyro, and Borax.

I knew that Pyro does not last long in sulfite and carbonate solutions, and I became upset with myself, for leaving the mixtures around in my lab. So in cleaning up my lab..., I remembered that Rodinal, does not do well with Borax, if left in a mixed solution longer than 4 to 6 hours, the chemical solution will start to break down, and with the same being true with Pyro. Unless the solutions are highly diluted with water, which then will lengthen the time to about 8 plus hours. before the solutions are totally worthless.

So I made two separate solutions, one Pyro and the other Borax, and mixed them with the diluted Rodinal. The Rodinal needed to be diluted first, before adding the Pyro and Borax. Because unlike PMK, the sodium hydroxide and borax are not pre-mixed and I did not want the chemical reaction that takes place when one prepares PMK.

Since Rodinal already contains the hydroxide, I just needed to add the Borax to give me the Sodium Metaborate effect I wanted; about 10 ml. Then I add 20 ml the Pyro to get my p-Amino/Pyro combination I wanted.

This gave me even better results, because I believe that the borax helped to reduce the grain levels and improve edge effect and sharpness. Plus by controlling the amounts of Pyro and Borax levels independently, one may obtain a varying degree of results. In fact, I think that the amount of borax that I added was too low. So I will increase it by 2 ml enactments until I get the results that pleases me.

Thank You

KennyE


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