Microdol-x / D-25

[Tom Hoskinson]

Yup - there is magic pixie dust in Microdol-X in the form of a benzophone compund that acts as an anti-silvering agent. This is designed to suppress some of the solvent action that would otherwise cost you even more film speed and possibly induce dichroic fog.

I'd like a technical reference or some mass spectrometer results, please. The current Kodak MSDS (and previous ones) shows no hint of a benzophone. The current MSDS does show boric anhydride.

 

[BarrieB]

Greetings Lee C. You mention Microdol X at 80% of time, OK if this is STOCK how long do you keep it? & how many sheets per Litre / Gallon ?
Thanks Barrie B.

 

[aldevo]

Tom-

No chemical constituent representing less than 1% (by mass) need be included in an MSDS.

And mass spectrometer results? Haven't got one handy...

But the presence of the benzophone additive in Microdol-X is well known. Heck, even Anchell & Troop mention it in the "Film Development Cookbook". It's in the chapter on super-fine grain developers.

 

[Jennifer]

Hi,
Here is something interesting. There are 3 benzophone's. They are labeled
Benzophone 1...Benzophone 3...Benzophone 4

The #3 is used as a UV blocker in sun block for your skin.

So which came first. Microdol-X or sun block.....
If I run out of sun block, I'll just rub some microdol-X on me !

Jennifer



The digital darkroom.....wonder what safelight they use

 

[lee]

Greetings Lee C. You mention Microdol X at 80% of time, OK if this is STOCK how long do you keep it? & how many sheets per Litre / Gallon ?
Thanks Barrie B.

Hi Barrie B.,

I keep a running count of the number sq inches I process in a gallon. I think Kodak recommends 320 sq inches per quart (just less than one liter) so that is 4x320=1280. so if you are shooting 4x5 that is 20 sq inches and that allows for 64 sheets of film. 5x7 will allow for about 30 sheets and 8x10 will allow 16. I think I remember that roll film is about 20 sq".

I make up a gallon and pour it into a tray. (really about a liter) when I am finished developing I pour it back into the jug. After a while you will probably want to filter the Microdol-x as you pour it into the tray. The solution gets a little silvery looking after awhile.

as to the 80% of time, I am assuming you have a standard time established already. From this established time do I take off 20%. The other thing that is important is to de-rate the film speed another stop. So, if you are using an EI of 400 then I normally shoot a film like that at 200. With this development schedule, you will want to expose the film at 100. This will support the shadows and you want that.

I use borax or metaborate or kodalk mixed as a 10% solution and this is used as a second bath. 4 minutes will be long enough in that bath. What is happening here is the densest part of the neg will exhaust pretty quickly and the #2 solutions will allow the thinner parts of negative to continue to be active. Then it is off to the fixer. This will give you a nice fat low contrast negative that will be easy to print. In places where you are running into reciprocity failure, this routine is an excellent solution and will not allow the contrast to jump off the scale.

 

[Tom Hoskinson]

Tom-

No chemical constituent representing less than 1% (by mass) need be included in an MSDS.

And mass spectrometer results? Haven't got one handy...

But the presence of the benzophone additive in Microdol-X is well known. Heck, even Anchell & Troop mention it in the "Film Development Cookbook". It's in the chapter on super-fine grain developers.

No data, therefore no sale.

 

[Tom Hoskinson]

Hi,
Here is something interesting. There are 3 benzophone's. They are labeled
Benzophone 1...Benzophone 3...Benzophone 4

The #3 is used as a UV blocker in sun block for your skin.

So which came first. Microdol-X or sun block.....
If I run out of sun block, I'll just rub some microdol-X on me !

Jennifer

Not a good idea --- Microdol-X really does contain Metol...

 

[aldevo]

No data, therefore no sale.

Well, the best I can do is quote from the "Film Developing Cookbook" by Anchell & Troop...

From page 70:

"The agent used in Microdol-X is probably a benzophone, referred to as an "anti-stain" agent (this class of chemical is also used n sunscreen products). Such anti-silvering agents might be useful if you would like PPD to work with modern films."

etc.

That's about as close as we're going to get to a confirmation. EK has never released the formula, nor would I expect them to do so at any time in the future.

 

[Tom Hoskinson]

Well, the best I can do is quote from the "Film Developing Cookbook" by Anchell & Troop...

From page 70:

"The agent used in Microdol-X is probably a benzophone, referred to as an "anti-stain" agent (this class of chemical is also used n sunscreen products). Such anti-silvering agents might be useful if you would like PPD to work with modern films."

etc.

That's about as close as we're going to get to a confirmation. EK has never released the formula, nor would I expect them to do so at any time in the future.

My 1994 edition of "The Darkroom Cookbook" by Anchell does not contain any speculation or reference about benzophones in any context. The 1994 volume contains nothing about Microdol-X at all.

I have no problem with speculations about the existance and possible functions of pixie dust - as long as they are labled as speculations or hypotheticals.

In my experience, one of the most important functions of pixie dust is to confuse anyone who is trying to reverse engineer the recipe.

If one is concerned about potential dichroic fog due to the high sulfite content of Microdol-X, the simple solution is to use the developer as a one-shot and/or dilute it with water.

 

[psvensson]

I've tried using sodium chloride in homebrew developers, and it almost always gave heavy dichroic fog, so I suspect that the danger of fogging with Microdol-X arises from its chloride content. Adding Calgon, another component of Microdol-X, to my homebrews took care of the fogging, so I would guess that that's the magical antisilvering compound.

Chloride in the developer sometimes gave very interesting grain - small and very well defined - but I was unable to get consistent results, possibly because of contaminant in the kosher salt, so I have given up that train of experiments for now.

 

[Tom Hoskinson]

I've tried using sodium chloride in homebrew developers, and it almost always gave heavy dichroic fog, so I suspect that the danger of fogging with Microdol-X arises from its chloride content. Adding Calgon, another component of Microdol-X, to my homebrews took care of the fogging, so I would guess that that's the magical antisilvering compound.

Chloride in the developer sometimes gave very interesting grain - small and very well defined - but I was unable to get consistent results, possibly because of contaminant in the kosher salt, so I have given up that train of experiments for now.

The sodium hexametaphosphate (Calgon) is a Calcium sequestering agent (i.e. water softener). Maybe your water is a problem source?

If Sodium Chloride is used as a homebrew developer additive, it must be Iodine free Sodium Chloride.

 

[psvensson]

The sodium hexametaphosphate (Calgon) is a Calcium sequestering agent (i.e. water softener). Maybe your water is a problem source?

Possibly, but I've never had dichroic fog with developers that lacked chloride. So the chloride, or whatever impurities it has, is part of the problem. I can't rule out that calcium plays a role too. I believe Calgon sequesters other metal ions besides calcium, but I've been unable to find a definitive source on that.

If Sodium Chloride is used as a homebrew developer additive, it must be Iodine free Sodium Chloride.

The kosher salt I use is allegedly free of added iodine, but it doesn't say how pure it is to begin with.

 

[dancqu]

The kosher salt I use is allegedly free of added iodine,
but it doesn't say how pure it is to begin with.

FX-1 and the like add iodine at the parts/million level. Any
halide added to a developer will suppress the solubility of the
film's or paper's silver halides. Physical development and fog
are reduced.

I see from a P. Dignan book of formulas some substitutes
formulated by R. W. Anderson. Microdol X; metol 7.5gr,
s. sulfite 100gr, s. bisulfite 7.5gr. He says his mix is
much lighter than the packaged. I think that likely
due to a lack of sodium chloride. Dan

 

[Tom Hoskinson]

...I see from a P. Dignan book of formulas some substitutes
formulated by R. W. Anderson. Microdol X; metol 7.5gr,
s. sulfite 100gr, s. bisulfite 7.5gr. He says his mix is
much lighter than the packaged. I think that likely
due to a lack of sodium chloride. Dan

This formula is posted in the APUG Chemical Recipes (with a sodium chloride comment by Pat Gainer).