Rod Smith wrote:

In article om,
"Brad Dow" writes:


Is a certain concentration of sodium sulfite critical to the keeping
qualities of developers that use metol as the only reducing agent? To
put the question in context, consider a hydroquinone-free variation on
DK-50:

metol 6g
sodium sulfite 30g
sodium metaborate 10g
postassium bromide 0.5g
water to make 1 liter

With the relatively low sulfite level of 3%, would such a developer be
less stable in storage (in full glass or nalgene bottles) than D76H or
D23, which call for 10% sodium sulfite? If so, what is the minimum
level of sulfite required for good keeping qualities?



I can't answer your question with respect to the developer you mention,
but Patrick Gainer has created some interesting NO-sulfite developers with
excellent keeping qualities. Most of Gainer's developers are
phenidone/ascorbic acid (PC) developers, though. Specifically, PC-Glycol
is made from phenidone and ascorbic acid in glycol with a separate
solution of carbonate. (The two are mixed together at time of use.) PC-TEA
consists of phenidone and ascorbic acid in triethanolamine (TEA), which
acts as both a solvent and an activator. Check
http://www.apug.org/forums/showthread.php?p=255352 for details.

IIRC, metol is soluble in propylene glycol but not in TEA. Thus, you might
be able to cross your DK-50 variant with PC-Glycol to get something
similar to DK-50 with excellent keeping qualities. I made my first batch
of PC-Glycol about a year ago and it's still going strong.



Metol is the hydrosulfate of 4(methyl-aminophenol) or some such thing.
The hydrosulfate is what makes it soluble in water. It is possible to
remove the hydrosulfate, which is sulfuric acid, and dissolve the Metol
base in TEA or glycol. This can lead to some interesting developers,
including a metol-ascorbic acid stock solution in either TEA or glycol.
It has more tanning ability than the phenidone version, which is
supposed to give it more sharpness due to the refraction of the gelatin
relief image. I'll dig up my notes and come back later with a recipe. It
doesn't require much heating: just enough to reduce the viscosity for
quicker mixing. Basically, the idea is to make a slurry with TEA, metol
and ascorbic acid, then add just enough water to make the TEA basic.
There may be a little precipitate of the sulfate, but it is possible to
make quite a concentrated stock in this manner.