I’m curious — Edwal FG7 “Automatic” two-bath developer

[Trask]

A seller on e^ay is offering a 40-50 year old (empty?) bottle of Edwal FG7 ($75, if you want it), and kindly provides good photos of the instructions on the bottle. I was interested to note that Edwal suggests using FG7 Automatic two-bath developer, using FG7 and “FG7 Solution B” — the company suggests the user see the FG7 technical bulletin.

It would seem a good bet that Solution B is an accelerator of some sort in water, but as the title says, I’m curious — so does anyone have an old Edwal FG7 bulletin with the info re: Solution B? I tried to find one using the Wayback Machine, but it seems to be having problems.....

 

[laingsoft]

Typically you'd split developers in order to keep the pH in an acceptable range so that the developing agent doesn't oxidize in air, but I'd also assume that it's some sort of accelerant in this case. Likely some hydroxide.

It could also be a fixer?

 

[mrosenlof]

Split developers usually have a solution A which contains all of the developing agents, and a solution B which is a basic solution, Kodalk (Sodium Metaborate), Sodium Carbonate, borax, lye, combinations of the above are likely suspects. A solution of 5g Sodium Carbonate in 1 liter of water is an easy place to start. Maybe some sulfite also.

The idea idea is that the process is relatively unaffected by time. maybe 3 minutes in A then directly into B for another 3 minutes or so. I've done some reading on divided developers but have never tried one, so I may be less than 100% correct here.

 

[craigclu]

I used to use FG7 quite a bit.... I have a very vague memory of them maybe calling the alternate method of using it as solution B? The alternate use was with sodium sulfite which added a solvent effect. I did not like the effect (mushy grain) and abandoned the method pretty quickly. FG7 in its later/last vestiges had packaging problems with the plastic bottles and would fail on the shelf. Their tech people were recommending moving your FG7 to glass bottles upon purchase. Shortly after that, they discontinued the product. They were quite proud of their product in their ads...

 

[Trask]

Thanks, everyone — I know about two-bath and split-developer processing; I’m sure that Michael R is correct that the FG7 Bath B is just an accelerant. I’m interested in his remark that “the more alkaline solution B is, the greater the risk of uneven development.” I been reading a lot recently about two-bath and split developers — including many of Michael R’s own informed comments — but never came across this suggestion that increased alkalinity can lead to uneven development. Is that the case only when speaking of a Bath B in two-bath or split developers, or would that apply even to “complete” developers like home-brew D76, for example. If one were to use Sodium Metaborate or Sodium Carbonate instead of Borax when mixing and using that one-bath developer, does using anything more alkaline that Borax run the risk of uneven development? My own experience is that it does not, but I’m interested to read what others may think.

And cragclu — thanks for the ad!