For no better reason than I had the materials on hand, I've developed a couple of rolls using the formula mentioned here:

Quote Originally Posted by Photo Engineer View Post
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.

Because of the extreme difficulty of obtaining Kodalk (Sodium metaborate) in the UK, I substituted Sodium Hydroxide + Borax as per this thread ; I've done this a couple of times now with no unexpected results.

I'm satisfied that I assembled the developer solution correctly, and I have used the Metol, KBr and Ascorbic acid recently for other developers with no unexpected results.

My first roll through (a week or two ago) was fine, and in fact was good enough to prompt me to try it again this evening, so I made up another batch of EAA ... but tonight I had an unexpected and puzzling result.

I used 5 minutes @ 20C as a starting point. My first 12-frame roll (135, from bulk) came out of the tank entirely fogged - the rebates were jet black; it looked like I had put it through a reversal process. Images were just discernible within the frames.

Assuming I'd somehow exposed the film when rolling it or when loading the tank (both tasks had however been carried out in total darkness, but one never knows), I tried another - with exactly the same result.

I tried a third roll from the same batch of film with a different developer - no problems; all developed as expected, clear rebates.

Then I tried the EAA again, but this time with a strip from a commercially loaded cassette (Lucky 100 as it was to hand and cheap); Same result - complete fogging, with just discernible images present. (I'd split the Lucky into three strips of 12, and tested the other strips with a different developer - all developed OK)

The obvious conclusion is that there was something awry with this batch of EAA, perhaps as a result of inadvertent contamination.

SO ... what contaminants might have produced this curious effect? I know that there are "fogging developers" used for reversal purposes, and I know that Sodium dithionite and Stannous chloride are used for those purposes, but I possess neither.

I post this as a curiosity rather than an earnest enquiry, and I'm sure someone will want to tell me I'd be better off using D76, or that nobody without a PhD in Chemistry should mix developers, but it would be nice to have some sort of hypothesis to explain what's occurred.