Experimental Fine Grain Developer EFG-1

[Alan Johnson]

EFG-1:
Metol............................10g
Sodium Ascorbate............50g
Borax..............................9g
Water to..........................1L
pH~6.5
Wear gloves,some people develop an allergic reaction to impurities in metol.
Develop Ilford Delta 100 20m 20C

A high concentration of the developing agents means EFG-1 works at low pH,reducing swelling of the emulsion and consequent grain.
It gives slightly more grain than Xtol 1+0,with higher acutance,see attached photomicrogaphs (btw,resolution~80 lppm on negative).See the gray area round the black card for grain comparison.

This is probably the finest grain obtainable from ascorbate without sulfite.
It might be possible to get finer grain by adding,say,80g/L sodium sulfite and adjusting the pH with Borax and/or Boric Acid to keep it below ~7.
I wonder if there are any comments on this approach, thanks.

 

[bwrules]

What's the advantage of metol over phenidone here?

 

[Photo Engineer]

Can you show an H&D curve of the two examples above? I really don't see grain that is that much finer, but I do seem to see a difference in contrast.

PE

 

[Ian Grant]

What's the advantage of metol over phenidone here?

Phenidone (and Dimezone) is a poor developing agent on it's own giving low contrast, it comes into it's own when used in addition to a second developing agent, most commonly Hydroquinone but also Glycin, Pyrocatechin and Pyrogallol. Phenidone is used on it's own in very specialist low contrast developers used for non standard applications. POTA was formulated for photographing the extreme contrasts of Nuclear test explosions later being used to give continuous tones with Technical Pan which had inherent high contrast,

Metol on it's own is used in a number of developers, D23/D25, ID-3/D165 etc.

Ian

 

[nworth]

To me, EFG-1 looks a bit more grainy but sharper than Xtol. But the sharpness could be an illusion if the contrast is higher. It is very hard to tell with these high contrast images. For grain and sharpness comparisons, images have to be developed to the same contrast. I echo PE's request for curves.

 

[Alan Johnson]

bwrules,

Scientifically,I have to answer "don't know" if metol gives finer grain than phenidone.
I used metol as it is used in the fine grain developers Microdol-X and Perceptol I believe.

PE, nworth,

I don't have H&D curves,agree there is a difference in contrast.
However, IMO the photomicrographs show the grain with EFG-1 is not significantly less than that with Xtol 1+0.
Can metol-ascorbate give finer grain than Xtol if sulfite is added?
No metol-hydroquinone-sulfite fine grain developer exists I believe.
If lowering the pH for MQ does not work, why should it work for MA?
Perhaps ascorbate does not give the hydroquinone effect,infectious development.

 

[Photo Engineer]

Perhaps there is more grain, but we cannot see it in the EFG due to higher contrast. BTDT.

Sorry, I need curves.

PE

 

[Alan Johnson]

My result, I only have the scans attached, is that the metol-ascorbate developer DS-2, pH~9.8 gives more grain than Xtol, pH~8.2.

 

[Gerald C Koch]

My result, I only have the scans attached, is that the metol-ascorbate developer DS-2, pH~9.8 gives more grain than Xtol, pH~8.2.

The DS-2 scan appears to have a higher density and contrast than the Xtol scan. Comparing two developers really requires that density and contrast must be the same.

 

[Alan Johnson]

Yes, you are right ,I don't have the reliable data.Also the amount of sulfite is different which muddies the water furthur.
That leaves Michael's point regarding if it is known that changing pH changes grain size.

 

[bwrules]

Wonder if this has any advantage over PC-TEA, which is a phenidone-ascorbic acid developer.

 

[Alan Johnson]

EFG-1 has a lower pH,6.5, than PC-TEA which has a pH of about 9 for the 1:50.The pH of the 1:100 can fall to near 8 during use.Some time ago I tested it and found the grain size even with the 1:100 never gets as fine as that from Xtol 1+0. I don't have any scans etc to show this though.

 

[bwrules]

Interesting about Xtol vs. PC-TEA. I have some fine-grained negs (FP4+) done in PC-TEA. 11x14 looks great with fine grain and good detail, although Xtol could be more finer grained, who knows.

 

[nworth]

Perhaps we are going somewhat astray. While a valid comparison of grain and sharpness requires that the film be developed to the same contrast, and I would still like to see curves and results with these controls, EFG-1 still appears to be a very sharp developer with moderately good grain characteristics. It deserves some attention and probably some more work.

 

[Photo Engineer]

Development must be done to match 2 out of the 4 parameters of Speed, Grain Contrast and Sharpness. This all assumes that contrast and speed are equal! So we need assured of two out of these here, namely Speed and Contrast. And they both must be equal.

PE

 

[Alan Johnson]

Thanks for the suggestions.I may try adding sodium chloride,or starting again with added buffered sulfite, and develop to get the contrast the same as Xtol.It is much easier to do initial grain tests with a scanner, I appreciate this is not how Kodak would have done them but they had more money and no scanner.
It might produce a minor curiosity but it would be rather unexpected if the developer turned out to give as fine grain as Microdol or Perceptol with increased film speed.I measured the pH of my (old) bottle of Perceptol, it is~7.5.

 

[Alan Johnson]

From the Film Developing Cookbook p70:
"When a metol developer is diluted,highlight development is restrained more than shadow development........."
With EFG-1 metol is not diluted so it will likely give high contrast.
I may add 30g/L sodium chloride and post the result in this thread.

 

[Alan Johnson]

Please see attached scans of Ilford Delta 100 developed in EFG-1, EFG-1 + 30g/L sodium chloride, Xtol 1+0,and Perceptol 1+0.(My scanner only resolves ~45 lppm, the scans are of 0.1 in square sections of negative.)
EFG-1 gives probably about the finest grain that can be obtained by increasing the developer concentration and reducing the pH. IMO the scans show no detectable difference in grain with Xtol or with 30g/L sodium chloride addition.Perceptol gives the finest grain of the four.

 

[Alan Johnson]

Here are higher resolution photomicrographs.
The apparent sharpness depends on how well these are focussed but IMO the probability is that EFG-1 has higher acutance than Xtol.The effect of NaCl is still hard to see but it may slightly reduce grain,possibly to Xtol levels.
I don't think using high concentration of metol and ascorbate and reducing the pH, in absence of sulfite, is going to provide super fine grain like Perceptol.

 

[Ian Grant]

Pyrocatechin can be used with a silver solvent to give very fine grain alongside excellent acutance. A Dr Eugene Mayer proposed a formula during WWII (1943) a bit like the Windisch surface developer but with Potassium Thiocyanate.

If you took a formula like the surface developer Hans Windisch published or even Pyrocat HD adding Sodium Chloride should give much finer grain, because the developers work at a higher pH than Microdol (X) & Perceptol there should be far less drop in effective film speeds.

Ian

 

[Ian Grant]

Closer to Perceptol/Microdol, it's related to the MCM100 Super fine grain developer. Pyrocatechin was used by Kodak in HC110 in one of it's formulations.

Meritol - PPD/Pyrocatechin was a good fine grain developing agent combination and Pyrocatechin had largely gone out of use until Sandy King's Pyrocat HD.

Ian

 

[Ian Grant]

Johnsons took Meritol based developers a lot further but their work was lost when the company closed it's chemical division in the 1970's, they were the oldest of all commercial photographic companies - they supplied Silver Nitrate to Fox Talbot.

There's potential to revisit Meritol & Pyrocatechin in other combinations and come up with new formulae. Some developers went out of use because of problems with Kodak films, they were more prone to Dichroic fogging compared to competitors films, hence Kodak's move from DK20 to Microdol then Microdol-X.

Kodak used Pyrocatechin with Ascorbic acid (or Ascorbate can't remember which off the top of my head) in a Graphics developer and also in HC110, so they were well aware of it's benefits. It would be interesting to know whether the Pyrocatechin version of HC110 gave finer grain & better films speed.

A problem with Kodak commercial developers is that they do evolve and change slightly, there were at least two variations of Microdol and also Microdol-X. Their films varied as well depending on the country of manufacture and not all developers were sold in every country, so for example Kodinol (Kodak's version of Rodinal) and HDD were never sold in the US.

A major problem with film developers is there are so many avenues one can take, I've been looking specifically at the Pyrocatechin variations/combinations etc, and there were many commercial developers from smaller companies.

Ian

 

[Gerald C Koch]

Among the reasons why developers like MCM100 are no longer used are

o they didn't work as claimed;
o improvments in emulsion technolgy made their use unnecessary;
o they did not work well with modern films;
o they caused a severe degradation in resolution;
o they caused a loss in film speed;
o they were toxic.

 

[Photo Engineer]

Good points Jerry. AAMOF, at Kodak, we were working on a whole new family of HR/FG developers at the time that B&W programs went into decline in 1988 or thereabouts. They took an entirely different approach than any of the existing developers. Of course, you might consider Xtol to be the only one commercialized, but there were others.

I've done some work here on some of the ideas and they are not all that hard to implement. Nothing I've seen here really has any impact on that work or any other work unless the contrast of all of the posted images can be normalized by processing so that we have matches in speed, grain and contrast.

We had teams of dozens of engineers working on new developing agents and new developer formulations. It is not easy to just stumble on a magic bullet. My next door neighbor was a member of one of those teams and we have talked over the fence about some of the problems facing the designer of developers. ( I was going to say developers of developers but that seemed a bit over the top! )

PE

 

[Alan Johnson]

PE,
I wonder if any of the Kodak work is ever likely to be disclosed or if it is filed away and the engineers to whom you refer subject to confidentality agreements.