What is a "clean working" developer?

[Steve Goldstein]

I've come across the phrase "clean working" a number of times, most frequently in discussions of D-23, and am wondering what it means. The implication is that developers lacking this characteristic are less worthy of consideration or somehow defective. So what, exactly, characterizes a "clean working" developer? How is it measured? Are there degrees of "cleanliness"? What term would properly be applied to a developer lacking these characteristics - unclean? Dirty?

None of the developers I've used over many years (D-76, HC-110, DK-76b, Microdol-X real and substitute formulae, PMK, and Pyrocat-HD) strike me as not "clean-working". Even staining pyro developers stain negatives in a very particular manner that I'd be hard-pressed to consider problematic. I've produced fine, printable negatives with various films using all of them, and have no complaints with the technical quality of any negative so produced (though the images themselves can usually be improved upon!).

The descriptor "clean-working" strikes me as a relatively meaningless but catchy phrase written long ago by Somebody Famous quoted and requoted so often that it has taken on the aura of truth, or meaning. Is there something I'm not sufficiently skilled, sensitive, or knowledgeable enough to see? Are "clean working" developers the photographic equivalent to the emperor's new clothes? Does anybody really know?

 

[Ian Grant]

Clean working developers have a lower Dmin, the developers that are not clean working have a high solvent effect as Michael states and include D23, D76 etc. Cutting the Sulphite level actually gives better Dmin assuming the negatives are processed to the same contrast.

In a replenished developer like D76/ID-11 the increased bromide levels help keep the Dmin low. It's why there's a difference in quality between fresh D76 and seasoned/ripened replenished developer which gives optimal finer grain, tonality and sharpness - it's more like using D76 at 1+1

Ian

 

[Xmas]

pick a clone with low sulphite and potassium bromide for low fog option of pH buffer for longevity...

http://www.lostlabours.co.uk/photography/formulae/developers/devD76_variants.htm

 

[Thomas Bertilsson]

I've read this term a few times, and the only time I was lured in to try a 'clean working' developer was the Fine Art Photo Supply product called FA-1027. The owner of that now defunct business, Anthony Guidice, wrote a piece about the developer and that it was clean working. It was implied that the printing times were shorter, and I remember that the processed negatives were exceptionally clear in their appearance with very low base fog, compared to just about every other developer I have tried, and yes the negatives did print a bit faster and it was a very good product.
I believe you can still purchase it from Photographers' Formulary, who bought that business many years ago.

I assumed that the faster print exposure times had to do with exceptionally low base fog.

 

[Ian Grant]

Ian I don't understand what the base fog level has to do with "clean working". First off, the difference in base fog between say fresh D-76 and virtually any other general purpose solvent developer I've ever tested is extremely small - more or less within the margin of error when it comes to process control (even in automated systems I would think). We're talking 1 or 2 density units.

It's quite simple the base of the film is cleaner (clearer), this results in slightly better shadow details as the base fog is additive to the exposed silver image.

Probably the best way to see the difference is process a film in D76/ID-11 and a similar film in PQ Universal, or Rodinal to the same contrast then compare the two side by side and print them. Because it's silver rather than a dye it's not the same as printing through a mild ND and has a slight effect on sharpness and grain.

Ian

 

[Xmas]

It may be more critical than Ian suggests if you are pushing when the fog level will be higher.

Think they do the ISO tests with a clean working soup?

 

[removed account4]

Clean working developers have a lower Dmin, the developers that are not clean working have a high solvent effect as Michael states and include D23, D76 etc. Cutting the Sulphite level actually gives better Dmin assuming the negatives are processed to the same contrast.

In a replenished developer like D76/ID-11 the increased bromide levels help keep the Dmin low. It's why there's a difference in quality between fresh D76 and seasoned/ripened replenished developer which gives optimal finer grain, tonality and sharpness - it's more like using D76 at 1+1

Ian

ian

is the term "crisp" usually used along side clean working?
i have read descriptions of a variety of developers in
the photo lab index over the years and the developer
are called both crisp and clean working ...
i always thought it meant gives a nice sharp grain, and contrast
and a "snappy" negative ...

 

[Rudeofus]

If you formulate a developer for highest possible ISO speed, you need to develop Silver Halide grains with very little exposure to the point where the differentiation between exposed grains and fog becomes harder and harder. As a result most speed increasing developers have to strike a balance between actual speed achieved and fog level. I have no personal experience with these, but both DD-X and TMAX developers are said to create a fair amount of fog - but at the same time give better speed than most other commercial developers.

Sometimes you don't care about that extra half or whatever stop of ISO speed, but you do want highly standardized negs across multiple films for efficient mass enlargement. You can control contrast by adjusting your dev time, but how do you control fog? Enter "clean working" developers which don't create fog.

 

[Steve Goldstein]

I'm glad I asked, this has been an interesting discussion and I've learned some things. Thanks everyone!

 

[Oren Grad]

A really good question! In 30+ years at this game, I've always understood "clean working" to mean "low base + fog density". But I can't cite chapter and verse of where I first picked up that notion.

Re Michael's comments, whether differences in B+F are in practice large enough to matter, or consistently match conventional wisdom about which film/developer combinations are better in that respect, is a different question. It's never made a difference to me in my own darkroom work, so I haven't invested the time to research it. But the idea - logically consistent or not, important for practical purposes or not - is out there.

 

[Ian Grant]

I have yet to see any evidence low fog is what is meant by "clean working" (and low fog relative to what?). The references I've seen to this term have always been in the context of re-use/replenish and/or machine processing.

See post #9 for some of Kodak's views on what clean working means to them.

Actually the two go hand in hand, if a developer has a tendency to dissolve and deposit colloidal silver it won't be as clean working in terms of base fog or in a replenished system.

Creawley wrote about Adox Borax MQ being cleaner working than D76 due to it having less Sulphite, it also gives finer grain, better sharpness and tonality plus is 1/3 of a stop faster. As it's related to the old ASA developer it gives box speed.

ian

is the term "crisp" usually used along side clean working?
i have read descriptions of a variety of developers in
the photo lab index over the years and the developer
are called both crisp and clean working ...
i always thought it meant gives a nice sharp grain, and contrast
and a "snappy" negative ...

Yes, another term we hear is mushy grain for D76. It's no coincidence that cleaner working developers give crisper grain and usually better sharpness.

Michael mentions Xtol and it beats D76 in all these areas, it's cleaner working, finer grain, better sharpness, that's my experience and Kodaks own claims.

Ian

 

[Rudeofus]

Creawley wrote about Adox Borax MQ being cleaner working than D76 due to it having less Sulphite, it also gives finer grain, better sharpness and tonality plus is 1/3 of a stop faster.

Michael mentions Xtol and it beats D76 in all these areas, it's cleaner working, finer grain, better sharpness, that's my experience and Kodaks own claims.

Why did Kodak release Xtol, go through all the pain with Ascorbate instability, when Adox Borax MQ is claimed to accomplish the same by just lowering the Sulfite amount of D-76? Inquiring mind really wants to know ...


@Michael: In one of your recent threads PE referred to their Metol-Ascorbate test developer as "clean-working" developer. I don't know how they tested their prototype emulsions, but when I hear "test developer", I would assume "fresh mixed for the test", which means "tank sludge" should be a non issue.

 

[miha]

The one that doesn't stain your trays.

 

[Ian Grant]

Why did Kodak release Xtol, go through all the pain with Ascorbate instability, when Adox Borax MQ is claimed to accomplish the same by just lowering the Sulfite amount of D-76? Inquiring mind really wants to know ...

I never thought about it that way

However I used Adox Borax MQ replenished in a commercial lab for a number of years (early to mid 80's) and used to supply it to another lab as well and it's an extremely good developer. I also later used Xtol (replenished) commercially from it's release until 2007/8 when I move abroad.

The huge advantage of Xtol is it's self replenishing with fresh Xtol which is fairly unique.

Looking from a different perspective Kodak had spent years of research trying to improve D76 which is a derivation (in steps) from a Wellington & Ward MQ Borax developer. But they couldn't deviate far from the original formula, nor could Ilford, D76 was essentially an open source developer formula used around the world &made by numerous manufacturers.

Kodak had worked on Ascorbic acid developers quite early but Patents from European companies prevented them marketing an Xtol type developer until the Patents expired, but they also needed a big selling point before they could market a developer that could potentially replace D76. Xtol is of course more environmentally friendly as well as being a better all round developer than D76.

So while Adox Borax MQ give quite similar improvements over D76 Xtol has two the advantages, self replenishing and environmental friendliness.

Ian

 

[cliveh]

The one that doesn't stain your trays.

Or one that actually cleans the tank/tray during development.

 

[Steve Goldstein]

Actually the two go hand in hand, if a developer has a tendency to dissolve and deposit colloidal silver it won't be as clean working in terms of base fog or in a replenished system.

<snip>
Ian

So is that what's always going on in my print developer trays - deposition of colloidal silver? I've never done any scientific experiments, but it seems to be worse with Dektol/D-72 than with Ansco 130, even though both have roughly equivalent amounts of sodium sulfite per liter.

 

[Ian Grant]

And yet XTOL is a solvent developer in much the same way D-76 is. The replenishment difference is essentially one of lower developing agent sensitivity to bromide, and more buffering.

Yes Xtol's not an MQ developer affected by Bromide build up. Ilford's PQ Photofinishing developer Autophen (essentially a PQ variant of ID011/D76) behaves in a similar way but needs a dedicated replenisher (in fact there were two).

When I still shot a lot of 35mm I took far more interest in getting the best possible quality from my films, that turned out to be Rodinal and AP100 (latter APX100) or Tmax 100 - a superb film/developer combination, Xtol when it came out was just as good. It's small nuances and personal taste and also satifaction with the resulting images that counts.

Ian

 

[Harold33]

In Anchell & Troop's Cookbook, they use "clean working" in reference to the properties of a given developing agent (glycin and metol are clean working), not of a given developer.

 

[Rudeofus]

Rudi - we'd have to ask PE exactly what he meant by that when he referred to the Kodak bench M-C developer. Actually didn't PE post the formula here somewhere?

I vaguely remember that it is somewhere in one of Haist's books. I may be wrong, though, but will check tomorrow if nobody beats me to it. The surprising fact that they used Metol instead of Dimezone-S tells me that they wanted something that gave them zero fog (remember your low contrast devs based on Dimezone-S and their high fog).

 

[pdeeh]

the Metol-Ascorbic developer being referred to may be this one, ("EAA", for Elon Ascorbic Acid)

This is a very clean working developer, never sold, but used internally for testing photographic emulsions. It is a pure surface developer and does not have any solvent effects on buried image.

Elon-------------2.5 g
Ascorbic Acid---10.0 g
Kodalk----------35.0 g
KBr--------------0.4 g
Water to 1 liter

pH 9.8

Note the use of decimals.

PE

I think I remember reading him also say that they would make up this in large quantities, and that it was very stable "on the shelf" if made correctly.

 

[Gerald C Koch]

Two other developers described as being clean working are Kodak DK-50 and Defender/Dupont 16D.

 

[Ian Grant]

the Metol-Ascorbic developer being referred to may be this one, ("EAA", for Elon Ascorbic Acid)

I think I remember reading him also say that they would make up this in large quantities, and that it was very stable "on the shelf" if made correctly.

It fell foul of the US Patents (I have them archived on an external hard disk - a Swedish company from memory) that covered similar developers so it or a variant couldn't be sold commercially.

Ian

 

[Gerald C Koch]

Another developer described as being clean working is Kodak DK-50.

 

[Ian Grant]

Two other developers described as being clean working are Kodak DK-50 and Defender/Dupont 16D.

It's interesting that Kodak took the Wellington & Ward MQ Borax developer, evolved it to D50 (never published) then DK50, D61 (never published) & DK61. and finally D76 (and DK76) although they had a metol only Fine Grain developer first in the 1920's before D76 a precursor or Haist's hypotheoretical D76 variant with no Hydroquinone (and probably what he was really referring to in an Anchell book).

Ian

 

[markbarendt]

So where on the scale do Pyro developers fit?