Fomapan 400 shot at 25 - rescue?

MattiS · May 3, 2020

Hello,

last weel I put a Fomapan 400 in my "new" Pentax Espio 928. The camera takes the ISO setting from the film
cartridge. When the roll was exposed I found to my surprise that there is no DX coding on the
cartridge at all. According to the camera manual the camera sets itself to ISO 25 when no DX code is available. So instead of ISO400 I shot the roll with ISO 25.

Is there a chance to "repair" this during developing? There is nothing important on the film, but I would like to try to rescue it. At the moment I have Rodinal and D-76 on the shelf.

Thanks, Matti

petrk · May 3, 2020

Hi, the best would be to expose another roll of Foma 400 the same way, divide it to about three strips and develop them in different times and decide which is best.Then use this best time for the first roll.

If you have only this one, I can only guess using information from a datasheet. They publish curves for D76 which you have, so I would take the D76 at 20C, the development time about 2 minutes. Looking at curves in a datasheet, with 4 minutes you get a low contrasty EI about 130-140, so I guess if you go to a half of it (i.e. 2 minutes), you could arrive somewhere between EI 50-100, which will yield a very low contrasty negatives, probably little dense, but they should be acceptable for other work.

pentaxuser · May 3, 2020

MattiS I hope you will shows us the negatives if you try what petrk says. It is always interesting to see what the range of a film is in terms of over exposure of 4 stops in this case.

Thanks

pentaxuser

Agulliver · May 3, 2020

So you've over exposed by four stops. And as you say, D76 at usual temperatures is 1:55 according to the MDC. You could try developing for 100ISO and living with the two stop over exposure depending on what the subject matter was? Or diluting some developer just for this? If you dilute 1+3 the development time is more like 5:30 to 5:45 minutes for ISO25

removed account4 · May 3, 2020

hi Matti
do you have instant coffee and vitamins c and baking soda / washing soda? if you do ..
develop it in caffenol C, tablespoon recipe and process the film for 8minutes agitate 1st min, then 10S/min after.
I regularly over expose film by 3-5 stops. LOVE caffenol. it will print and scan like a dream.

Donald Qualls · May 3, 2020

jnantz said:
hi Matti
do you have instant coffee and vitamins c and baking soda / washing soda? if you do ..
develop it in caffenol C, tablespoon recipe and process the film for 8minutes agitate 1st min, then 10S/min after.
I regularly over expose film by 3-5 stops. LOVE caffenol. it will print and scan like a dream.

Don't use baking soda to make Caffenol. Washing soda (also sold as soda ash at swimming pool suppliers) is significantly higher pH than baking soda, and the developer will be much slower, if it works at all, with baking soda than it would be with washing soda.

The rest of this is pretty good advice. You want to look for a "speed losing" developer and then pull at least two stops.

Rodinal is a speed losing developer (about 1/3 to 2/3 stop true speed loss with most films), in most processes; I'd go for Rodinal 1+49 and cut development time to half of the standard for your film. You should get negatives that will be printable that way. Another option, if you have some (or know someone who does) would be to process your film in Df96 monobath at 68F with continuous agitation. This will give a 2-stop pull along with most of a stop of true speed loss (due to fixing happening faster with high agitation and development being slowed at lower than standard temperature for this soup). Cinestill has an extensive chart for how to do this kind of pull with their monobath.

Kino · May 3, 2020

Along the lines above, Haist (pg 372 to 374) speaks of using Sodium Thiosulfate (Hypo/fix) added to D-76 as strong silver solvent for Fine-grain developers that has the effect of emulsion speed loss.

The "Turner Solvent Formula" or (MCW1 later), was made by adding 6ml of a 50% solution of Sodium Thiosulfate to 1000 parts of D-76, which slightly lowered the emulsion speed of normal D-76 with about half the grain.

He goes on to speak of the MCW 2, MCW 2A and MCW 3 formulas, which are NOT based on stock D-76, which are extreme fine grain developers that have the ability to excessively lower emulsion speed depending upon the amount of Sodium Thiosulfate introduced.

But being as the OP only has D-76 and Rodinal, that's just a point of interest and not really of practical use, but looks like a real avenue to explore in making very fine grained negatives using over exposure and under development.

removed account4 · May 3, 2020

Donald Qualls said:
Don't use baking soda to make Caffenol.

sorry to not add this before if one takes the baking soda and puts it in the toaster oven in a small heat proof open container .. the purging of the moisture will convert it to washing soda. i wish i could remember the conversion factor so one can just use baking soda directly, someone in the caffneol bloggisphere figured out a few years ago, from what this expert said its a weight thing..

MattiS · May 3, 2020

There are some very good ideas coming up and I´ll spend another roll of film to check the Caffenol way. Just have to get some soda.
Additionally I just found some packs of Perceptol and Microphen in one of my darkroom boxes. From what I read Perceptol might be a possibility, too.

reddesert · May 3, 2020

I don't have any experience with Fomapan 400, but IME negative films are relatively tolerant of overexposure, I could see using a dilute developer and developing to a recommended time for EI 100, but I wouldn't try to do a 3 stop pull or develop for only 2 minutes. That seems like a recipe for flat and/or uneven development.

Adrian Bacon · May 3, 2020

MattiS said:
Hello,

last weel I put a Fomapan 400 in my "new" Pentax Espio 928. The camera takes the ISO setting from the film
cartridge. When the roll was exposed I found to my surprise that there is no DX coding on the
cartridge at all. According to the camera manual the camera sets itself to ISO 25 when no DX code is available. So instead of ISO400 I shot the roll with ISO 25.

Is there a chance to "repair" this during developing? There is nothing important on the film, but I would like to try to rescue it. At the moment I have Rodinal and D-76 on the shelf.

Thanks, Matti

Fomapan 400 has a real speed of 160-200 ISO at ISO contrast, so you really only over exposed it by 2-3 stops. The data sheet for it: http://www.fomausa.com/pdf/Fomapan_400.pdf shows that you can pull the ISO down quite a lot with a shorter development time, so I'd maybe try 5 minutes at 20C in D-76 stock. A 2-3 stop over exposure isn't that big of a deal if you develop to reasonably normal contrast, or even a little flat.

Donald Qualls · May 3, 2020

jnantz said:
sorry to not add this before if one takes the baking soda and puts it in the toaster oven in a small heat proof open container .. the purging of the moisture will convert it to washing soda.

Well, almost. Heating baking soda sufficiently will drive off carbon dioxide and chemically convert the powder from sodium bicarbonate to sodium carbonate. This process will also drive off the water, so you get the anhydrous rather than the monohydrate that's sold for laundry use. If your formula calls for anhydrous, you'd need to compensate, but every Caffenol recipe I've seen since I first used it in 2003 calls for actual washing soda, which is the monohydrate, so you should be good to go. Just do your measurement after converting the baking soda.

If you try the conversion, you'll want to spread the baking soda in a layer a few millimeters thick in a flat pan, put it in an oven or toaster oven (I don't remember the minimum temperature, but regular baking temperature of 350F should work), and look in on it periodically. The powder will start to form little craters as the carbon dioxide comes off; when it stops outgassing (ideally, when it stops losing weight, but you're unlikely to have a way to track the weight as you cook it) it's done.

You CANNOT convert by using more of the wrong kind of soda. You'll still get a too-low pH, because baking soda has a lower solution pH at any strength than washing soda.

fs999 · May 4, 2020

Donald Qualls said:
but every Caffenol recipe I've seen since I first used it in 2003 calls for actual washing soda, which is the monohydrate, so you should be good to go. Just do your measurement after converting the baking soda.

All the Caffenol recipes I've seen are for anhydrous washing soda. If you want to use monohydrate, multiply by 2.7

koraks · May 4, 2020

fs999 said:
All the Caffenol recipes I've seen are for anhydrous washing soda.

That's odd, as washing soda is virtually never sold in anhydrous form in my experience. All I get here is the decahydrate. The conversion factor for anhydrous vs monohydrate is also not 2.7, it's 1.17. The 2.7 factor is used if the recipe specifies anhydrous but you use decahydrate. Most photographic formulas (not specifically caffenol, but regular photochemistry) assume the monohydrate if it's not further specified.

Here is a conversion table I once made for sodium carbonate:

Vertical: toHorizontal: from	Anhydrous	Monohydrate	Heptahydrate	Decahydrate
Anhydrous	1	0.85	0.46	0.37
Monohydrate	1.17	1	0.53	0.43
Heptahydrate	2.19	1.87	1	0.81
Decahydrate	2.70	2.31	1.23	1

So if for example a recipe calls for 10g of monohydrate but you have decahydrate on hand, according to the table above, the conversion factor is 2.31 (from: monohydrate to: decahydrate) and you can use 23.1g decahydrate instead of 10g monohydrate.

Juan Valdenebro · May 4, 2020

With Perceptol or Mic-X (developers requiring twice the light a standard developer does) your frames will be fine, inside film's latitude... If you did direct sun, those will be nearly perfect for short development... I'd say you could even wet print those frames !

fs999 · May 5, 2020

koraks said:
That's odd, as washing soda is virtually never sold in anhydrous form in my experience. All I get here is the decahydrate. The conversion factor for anhydrous vs monohydrate is also not 2.7, it's 1.17. The 2.7 factor is used if the recipe specifies anhydrous but you use decahydrate. Most photographic formulas (not specifically caffenol, but regular photochemistry) assume the monohydrate if it's not further specified.

Sorry I meant decahydrate.

In Europe you can find it easily in anhydrous form. I use a German brand Holste or Heitmann. But you can find other, it is also used for swimming pools...

MattiS · May 5, 2020

So, the camera is prepared for another roll of Foma 400, Luckily the camera is able to bracket from -3 to +3, so I can shoot a test roll to compare D76, Perceptol, Rodinal and Caffenol for the sake of science.

It was no problem to get all the ingredients for Caffenol, but I still wonder which type of soda it is. According to this thread it is the anhydrous type.

koraks · May 5, 2020

The index number gives a usable clue: if I google it, it suggests that it is equivalent to CAS 497-19-8, which is anhydrous sodium carbonate. The recipes on this page seem to assume anhydrous, suggested by the conversion factors they use for 'crystalline' soda: https://www.caffenol.org/recipes/ It's a bit unfortunate that so few recipes are explicit on the species they call for, but in this case, it can still be determined.

MattiS · May 5, 2020

Digged really deep in one of my darkroom boxes and this came up - should be doubtless the real stuff from 1990... .

bernard_L · May 5, 2020

David Vestal exposed one scene on Tri-X at various EI values. The scene is not of particularly low contrast: an interior, part shade, part sunlit, with a view through a window.
He repeatedly halved the EI from 1600 down to 0.37. He notes that the first correct exposure is EI 200. And that contrast is normal down to EI 3 (of course, exposure when printing increases). At EI 1.5 and lower David Vestal notes that the contrast is lower (shouldering) which requires switching to grade 3 paper. No fancy developer, caffenol, stand development. or the like. He does not even state (as far as I could see) which developer he used (I'd bet D-76), because his point is that the reader should perform the same experiment for himself. He even made a duplicate series that were developed by a commercial lab; back then (seventies) commercial labs would practice "bulletproof" development.
David Vestal, The Craft of Photography.

So (apart from Fomapan being a different film from the '70s version of Tri-X) your EI 25 exposure is nothing exotic. If you decrease development time too much, this will result in low contrast that may cause difficulties in printing.

I see on photo forums (fora??) some confusion as to the cause-effect relationships between (1) scene dynamic range; (2) development time to achieve negative density range suitable for "normal" paper; (3) effective useful EI.

removed account4 · May 5, 2020

Donald Qualls said:
Well, almost. Heating baking soda sufficiently will drive off carbon dioxide and chemically convert the powder from sodium bicarbonate to sodium carbonate. This process will also drive off the water, so you get the anhydrous rather than the monohydrate that's sold for laundry use. If your formula calls for anhydrous, you'd need to compensate, but every Caffenol recipe I've seen since I first used it in 2003 calls for actual washing soda, which is the monohydrate, so you should be good to go. Just do your measurement after converting the baking soda.

If you try the conversion, you'll want to spread the baking soda in a layer a few millimeters thick in a flat pan, put it in an oven or toaster oven (I don't remember the minimum temperature, but regular baking temperature of 350F should work), and look in on it periodically. The powder will start to form little craters as the carbon dioxide comes off; when it stops outgassing (ideally, when it stops losing weight, but you're unlikely to have a way to track the weight as you cook it) it's done.

You CANNOT convert by using more of the wrong kind of soda. You'll still get a too-low pH, because baking soda has a lower solution pH at any strength than washing soda.

Thanks Donald !

fs999 · May 6, 2020

I've made my own list with all the tested versions CLCS give best results :

NB23 · May 6, 2020

I shot tmax 3200 at iso 100 and that’s one of my most beautiful negative EVER. It should be common practice to always shoot any film at 1/2 box speed as a start.

koraks · May 6, 2020

That's a really nice overview @fs999 ! I think you've posted it before and it's very convenient and well done.

miha · May 6, 2020

NB23 said:
I shot tmax 3200 at iso 100 and that’s one of my most beautiful negative EVER. It should be common practice to always shoot any film at 1/2 box speed as a start.

Any but slide!

Fomapan 400 shot at 25 - rescue?

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