I seem to have accidentally developed a positive instead of a negative (!?)

[Etienne]

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OK, so I've been using my Leica CL rangefinder primarily for taking pictures to develop with Caffenol and fix with table salt. This weekend I went for a walk in frosty Gothenburg and exposed a roll of Fomapan 100. Later in the evening, with my brain mostly on auto-pilot, I start preparing the Caffenol for development... Water, instant coffee, sodium carbonate, ascorbic acid... Mix, cool, etc...

- "Hmm, the liquid smells slightly different... Never mind..."

Into the developing tank it goes. A few minutes minutes later I dump the developer, rinse, and in goes the fixing solution saturated with table salt. So far so good. 

About 2 hours later I go to take a sneak peak on the progress (FYI: it takes a very long time to fix and clear with table salt).
WTF! It looks really crappy! Usually the negatives look rather decent by now, but this is a total disaster! The film has not cleared much and the exposed areas are really vague.

So now I'm in total fault tracing mode. And it did not take long to figure out were I went wrong.
It seems my wife bought some "Hjorthornssalt" (Ammonium Carbonate) recently, from the same brand as the ascorbic acid, and stored it in the same place in the pantry. The packages look very similar, and contain a visually similar white powder. I did of course not think of actually reading the label (🙃) before mixing it into the Caffenol... (Yes, yes, I know it is my fault...)

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I was of course 99,9% certain that the whole roll was ruined. But in some weird and desperate attempt to maybe salvage the frames I prepared a fresh batch of correctly mixed Caffenol and poured it into the developing tank. A few minutes later I dump the developer and poured in a new batch of table salt fixer solution. I then left it overnight and hoped for a miracle.

The next day things looked rather dim. The film looked quite opaque and I could barely see any of the images:

- "Is my mind playing tricks on me, or are these faint images positives!?!? They definitely look like positives..."

Sure, these images are practically useless due the the low contrast. But nevertheless, they are positive... Very unexpected!
(Sorry for not treating the film better. I was not exactly cautious about dust and small debris since I was planning on throwing the whole roll in the trash anyway)

After digitizing some select frames as best I could, and then bashing them around in PS and CaptureOne, I managed to obtain some fairly acceptable images to keep as some sort of memento from the occasion. Here is one of the better ones:

Note that although most images were positive, some had become some kind of weird mix between positive and negative:

The big question is how did all this happen? Well, I'm not sure, but my best guess is that I must have mimicked the reversal process in some way by my initial "development", then "re-exposed" during my sneak peak at the first fixing, and finally re-developed and fixed properly... Anyhow, I find it rather amazing considering that this whole thing was purely accidental and unintentional, and still produced some sort of result. If anyone has a better explanation I would love to hear about it. 

So in summary I lost most of my frames and the ones I recovered were not of great visual quality, but it was still a fun (although unexpected) experience in the end.   

Edited December 28, 2021 by Etienne
typo...

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[Pyrogallol]

Interesting.

I have tried coffee and washing soda as developer in the past and still have some old coffee saved to use next time. But I used normal photographic fixer.

Your very weak fixing must have helped produce something like a reversal film process, develop-bleach-reexpose-develop- fix.

On the other hand it might look like the image you see sometimes with a very thin negative, in certain light it can look like a positive. Or like a collodion positive. 

I don’t think I would use coffee as a regular developer, stick to Rodinal, Perceptol, Tanol, Pyro etc.

[Etienne]

Indeed, the most reasonable explanation seems to be some sort of quasi reversal process taking place... Unless the Ammonium carbonate actually contributed to something?
Although I can't remember the images appearing positive during my sneak preview after the first "development", but I was not exactly looking for that particular detail. 

I can also add that the positive image is significantly more visual on the emulsion side. But this is not odd as it happens for negatives as well if they come out on a film that is not clear.

Anyhow, this particular film appears positive up from all angles and in all lights I have viewed them in, so it is definitely not caused by a very specific kind of light or a particular viewing angle (like for example an old TFT-screen that can appear to have inverted colours if viewed from a steep angle).

-  

On a separate note, I generally have good results with Caffenol and table salt fixer. It is of course not equivalent to "professional" development, but definitely usable, and there is a real MacGyver-type satisfaction in using only household items to develop film.
But it took lots of experimenting to establishing a process that works for me and the ingredients I can get hold of. The major improvement was when I tried Fomapan (in particular Fomapan 100). That film gives significantly better results than anything else I have tried.

Edited December 28, 2021 by Etienne

[Etienne]

Small update: 

Now, about a day and a half later, the film is close to completely blank. Only a few areas with very heavy light exposure remain as faint dark areas (negative). 
Fixing has obviously failed.

Edited December 28, 2021 by Etienne

[250swb]

I can see the point of Caffenol, I can see the point of salt fixer (if you really must), but why not just dunk the film in regular fixer as soon as you see something is wrong? It sounds to me like you've snatched defeat from the jaws of victory.

[Pyrogallol]

A very old topic of conversation,

http://foxtalbot.dmu.ac.uk/letters/transcriptFreetext.php?keystring=herschel&keystring2=&keystring3=&year1=1839&year2=1839&pageNumber=22&pageTotal=51&referringPage=1

https://talbot.bodleian.ox.ac.uk/2016/01/22/to-fix-or-not-to-fix-sir-john-herschels-question/

 

[adan]

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So you only developed the film part way, then exposed it to light (sneak peak), and more importantly - only fixed the film temporarily.

Look up the Sabattier Effect, which is created by re-exposing a partially-developed print (usually, but could be film) to light, and then developing it some more (sans agitation).

https://unblinkingeye.com/Articles/Solarization/solarization.html

That's essentially what you did.

It was a common pop-art photo effect in the 1960s-70s.

And yes, it is a very rough approximation of how reversal processes work. Expose film in camera, develop "real" negative, dissolve negative silver image, fog the rest of the silver (the unexposed and developed shadow silver) by holding it up to light (sneak peak ), develop the fogged shadow silver, fix resulting positive before it fades.

[Etienne]

3 hours ago, adan said:

Look up the Sabattier Effect, which is created by re-exposing a partially-developed print (usually, but could be film) to light, and then developing it some more (sans agitation).

https://unblinkingeye.com/Articles/Solarization/solarization.html

That's essentially what you did.

Ah, yes! This perfectly explains it. 

The table with columns 'A' to 'D' showing the effects of first and second exposure account for all observations. The majority of the pictures are 'B' to 'D', of which 'C' and 'D' have faded away now due to failed (second) fixing. The few really bright areas, 'A', are the only ones that remain as they were formed in the first development and first fixing. 'A' does of course not "contribute" to the positive image. 

... I'll perhaps try to do this intentionally sometime in the future. 😊

Edited January 5, 2022 by Etienne

[Michael Hiles]

From the images you provided above, the film looks to be badly underfixed. It seems to me that developing in coffee and fixing with table salt is rather crackpot.

Why not use something that is known to work…
 

[Etienne]

5 hours ago, Michael Hiles said:

 It seems to me that developing in coffee and fixing with table salt is rather crackpot.

Why not use something that is known to work…
 

Why on earth would you say that? I can confirm that it definitely works as intended when you don't accidentally add ammonium carbonate.

Did you read the whole post? 

Edited January 14, 2022 by Etienne

[Etienne]

Just in case someone is interested what a negative looks like when things go as planned, and you don't accidentally make silly mistakes when mixing... 

(I'm not saying Caffenol and table salt is just as good as developing with  "proper" chemicals. Just that it works, and usually gives waaaaay more decent results compared to the failed attempt I described in the original post.) 

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