High dilution with high pH

Relayer · Nov 6, 2010

Hello

Someone experimented with very high diluted film developers, but with increased pH to 11-13?

Ian Grant · Nov 6, 2010

The modern version of Rodinal (Agfa 1964 onwards) uses high dilutions and high pH, with starting pH of 14 for the concentrate, before dilution (contains excess Hydroxide).

The older version still made by Calbe uses a higher concentration of developing agent and has a lower pH 11.8 as there's no free (excess) Hydroxide.

Ian

Removed Account2 · Nov 6, 2010

If you start out with pH14 which is damn near concentrated NaOH, the rule of thumb is a dilution to 1:100 should land you at ph12 or there abouts, 1:50 at ph 12,4 or thereabouts.

In practice theres always a difference between theory and practice, of course!

Relayer · Nov 6, 2010

usually high pH used in pyro-developers. but I'm interesting something non-stain. now I'm experiment with DEA/MEA and low dev.agents concentration. by example

Metol 0.2g
Ascorbic acid 0.5g
Pyrocatechin 0.2g
DEA 6ml
Water 300ml

interesting that this developer is more than twice aggressive than ez-rodinal 1:50. so it can be diluted 1:1-1:4.
may be it still working with dilution 1:10 if we replace DEA to MEA - I don't know

Alan Johnson · Nov 6, 2010

http://www.pyrocat-hd.com/html/mixing.html
Pyrocat MC working solution (if my calculation is correct) has:

metol..............0.025g/L
ascorbic acid....0.04g/L
pyrocatechin....0.5g/L

So your developer has quite high metol & AA ,no need for high pH?

Athiril · Nov 6, 2010

Although not dilute... I made a concentrated developer @ high pH to be used at stock solution... with a lot of restrainer, for high contrast.

Ian Grant · Nov 6, 2010

Alan Johnson said:
http://www.pyrocat-hd.com/html/mixing.html
Pyrocat MC working solution (if my calculation is correct) has:

metol..............0.025g/L
ascorbic acid....0.04g/L
pyrocatechin....0.5g/L

So your developer has quite high metol & AA ,no need for high pH?

That's just Part A

Then add Part B the alkali

Ian

Relayer · Nov 6, 2010

Ian Grant said:
That's just Part A
Then add Part B the alkali

can be simple mixed in one part. I'm starting with Pyrocat-PC proportion

p-aminophenol - 0.015g
ascorbic acid - 0.012g
pyrocatechin - 0.15g
DEA 6ml
water 300ml

I'm use DEA because we need "carbonate" pH. its working ok and have same strength as original Pyrocat-PC. but single solution

Relayer · Nov 6, 2010

but Pyrocat-PC-DEA is still "slow" developer. so I modify it to high pH (MEA instead DEA) and slightly increase concentration. stock solution:

p-aminophenol - 0.03g
ascorbic acid - 0.025g
pyrocatechin - 0.2g
MEA 6ml
water 300ml

this modification (Pyrocat-PC-MEA) give me extra 1.5 stop on the same time as Pyrocat-PC-DEA. strength same as D76. tested on PolypanF 50@50 10min. D76 produce high contrast negatives on this film. Pyrocat-PC-MEA give me less and more acceptable contrast. next step - try to dilute it to 1:1..1:4

scan without postprocessing (no sharpness, noise remove etc), only resize, microtek 3600 dpi

100%

CBG · Nov 7, 2010

Can someone explain "DEA" and "MEA"? I'm only familiar with TEA / Triethanolamine.

Relayer · Nov 8, 2010

DEA (Diethanolamine) and MEA (Ethanolamine) like to TEA, but have more strong pH
graph from here
Dead Link Removed

RobertV · Nov 8, 2010

Here an example of AM50 the non-staining Pyrocatechine developer of Amaloco Photochemicals. pH=12,2 1+29. It's in fact a modification on Windisch Pyrocatechine developer. These type of developers (AM20) are from 1936.

AM50 (1+29) is a higher dilution AM20 (1+24).

Windisch is easy to make. Amaloco stopped production in Holland since 2008 after 79 years. Some patents/recepts were sold to their German distributor.

M7 + Summicron 2,0/50mm

Rollei Pan 25 @ E.I.25 in AM50 1+29 5:00Min

Alan Johnson · Nov 8, 2010

Regarding the stability of your developer in absence of air, I have some Mytol in a sealed glass bottle that still works after 4 years old (pH~8) so ascorbate is stable at pH 8.
I am testing some of Suzuki's DS-2 (pH~10) but that test has another 8 months to run to get to 1 year.
If you are using pH 12 the ascorbate might hydrolyse in absence of air, it may be interesting to test that as well.

Gerald C Koch · Nov 10, 2010

CBG said:
Can someone explain "DEA" and "MEA"? I'm only familiar with TEA / Triethanolamine.

MEA - monoethanolamine H2NCH2CH2OH Highest pH of series
DEA - diethanolamine HN(CH2CH2OH)2
TEA - triethanolamine N(CH2CH2OH)3 lowest pH

Gerald C Koch · Nov 14, 2010

The following developer may be of interest as it has a very high pH.

Kodak HDD developer

Kodak marketed this high acutance developer during the late 50's and early 60's. It was very popular in Europe but was never marketed in the US. The actual formula was never published, however Geoffrey Crawley suggested that the working solution had a composition similar to that given below.

In HDD the amount of sulfite is kept low in relation to the amount of Metol thus ensuring the controlled decomposition of the developing agent. This is in contrast to FX-1 which uses the minimal amount of Metol with sufficient sulfite to protect the developing agent.

Distilled water (50°C) …………………………………………… 750 ml
Metol ………………………………………………………………………………………… 2.0 g
Sodium sulfite (anhy) ……………………………………………… 1.0 g
Sodium hydroxide ………………………………………………………… 0.5 g
Potassium iodide, 0.001% ……………………………………… 5.0 ml
Distilled water to make ………………………………………… 1.0 l

This developer should be made up just before use as it does not keep.

Use full strength.

Gerald C Koch · Nov 14, 2010

Here is another high pH developer.

Catechol Compensating Developer

Stock Solution A

Distilled water (50°C) 750 ml
Potassium metabisulfite 12.0 g
Catechol 80.0 g
Distilled water to make 1.0 l

Stock Solution B

Distilled water (10°C) 750 ml
Sodium hydroxide 35.0 g
Distilled water to make 1.0 l

Usage

For use take 10 ml of A, 10 ml of B and 200 ml of water. For under-exposed negatives increase the amount of solution B. For over-exposed negatives add 1 ml of a 5% solution of potassium bromide.

Pierre Glafkides, "Photographic Chemistry", Fountain Press (London:1958), Vol I, p 74.

Gerald C Koch · Nov 14, 2010

MEA will not yield a very high pH and in small amounts offers no advantage over sodium hydroxide or sodium carbonate.

MEA is nasty stuff to work with and can cause burns and eye and lung damage.

Relayer · Nov 14, 2010

Gerald C Koch said:
MEA will not yield a very high pH and in small amounts offers no advantage over sodium hydroxide or sodium carbonate.

really pH difference between DEA and MEA isn't so important. do you know any other solvent similar to TEA/DEA/MEA with other pH values?

Gerald C Koch · Nov 14, 2010

It's unclear just what you are attempting to do which makes it hard to offer any specific advice. You can dissolve the developing agents in propylene glycol. Then take a small amount of this solution and add it to either a carbonate or hydroxide solution to make a working developer. Some developing agents like Metol are not soluble in organic solvents. In this case you would have to use p-aminophenol.

There are two types of developing agents. The first group are soft working and act on the toe of the H&D curve. This group also controls the D-Min of the curve and thus film speed. Metol and Phenidone are examples of this group. The second group controls the shoulder of the H&D curve and thus the D-Max and image contrast. Hydroquinone and ascorbic acid are examples of this group. Most developers use a member of each group and the ratio of the two agents determines the slope of the H&D curve and the character of the developer. Some developing agents may be used alone in general purpose developers. Examples are Metol, p-aminophenol and catechol. Phenidone and Dimezone must be used with a member of group two in order to produce usable contrast. When used alone they produce a very low contrast negative.

Relayer · Nov 14, 2010

Gerald C Koch said:
It's unclear just what you are attempting to do which makes it hard to offer any specific advice. You can dissolve the developing agents in propylene glycol. Then take a small amount of this solution and add it to either a carbonate or hydroxide solution to make a working developer.

now I'm experimenting with different single part concentrates mixed on DEA. it allow me make like sodium carbonate pH. but not high. I'm interesting anything other solvent that give me different pH.

why? because we can't make Kodak HDD as single part concentrate on glycol/DEA/MEA. we can replace Sodium sulfite with some amount of Sodium ascorbate. we can try to use Benzotriazole instead Potassium iodide (I guess that Benzotriazole can be dissolved in organic solvent). but as I know Sodium hydroxide can't be dissolved in glycol. we can use MEA. but pH will be less than original developer with hydroxide

PS maybe it's already known, but I found that borax can be dissolved in glycol.

Ian Grant · Nov 14, 2010

The Iodide is less important and with some (most modern) films irrelevant because it's in the emulsion of films like Tmax and Delta. Benzotriazole inhibits fine grain so is rarely used in film developers.

Ian

Photo Engineer · Nov 14, 2010

Mono-Ethanol-Amine (MEA) is a powerful Silver Halide solvent. Di-Ethanol-Amine (DEA) is a moderate Silver Halide solvent, whereas TEA is pretty much a non-solvent.

So, when you devise a developer using MEA, you have to be aware that you are doing a Microdol X type thingie on the formula making it highly solvent by means of the alkali. Good or bad? Your choice depending on the formulation.

PE

Gerald C Koch · Nov 15, 2010

Considering your earlier question, I did a bit of looking around and a pH of ~12 seems to be the maximum that can be obtained with an organic base. For example, a 25% solution of ethylenediamine has a pH of 11.9.

High dilution with high pH

Privacy & Transparency

Privacy & Transparency