Peter, Am I going to have more trouble with you English boys?
My term, as I recall, was the "old" cyanotype, as opposed to Mike Ware's
"new" cyanotype, so in the context, any formula up to one minute before
publication of the "new" formula is "old." Moreover, since many of the
principals in this discussion (including Dr. Ware himself, if memory
serves) have been using the Oxalate formula, and since the oxalate formula
is promulgated in as many places (more or less) as the Plain formula, and
since the principals are comparing the "New" to generally one or the other
of the "Old" without specifying which, it seems to me what is in Cassell's
has little to do with the current topic.
On top of which, there are MANY formulas in print from early 1800s on. A
look at Kosar gives some of the many ingredients possible and known.
You quote from Cassell:
> Solution A
>
> Ferric ammonium citrate (brown) 160 g per litre.
>
As we know, current formulas use green scales.
> Solution B
>
> potassium ferricyanide, 120 g per litre.
>
> These are stated to be best mixed in equal parts a week or ten days before use
> and kept in the dark - and then filtered just before use.
Modern chemicals are so much nicer -- we don't need to filter.
> There are full directions in Cassell's Cyclopaedia (p67-8), one part of which
> suggests that you should 'develop' with water containing 20 grains of citric
> acid per pint for a 'brighter' print. It also says to use lime free water and
> there are a few other hints and toning recipes.
I assume you have in mind the fact that in contemporary practice,
developing in first water with citric acid in it fogs the print seriously
(Kosar BTW knew this without my having to tell him), so I can only
conclude that this advice is on the order of the young man at my local
vegetable store who told me the leaves are the best part of the rhubarb,
and was crestfallen when I mentioned oxalic acid.
> Incidentally chemists will find enough hints in this work to enable the use of
> much cheaper and more readily available iron compounds than ferric ammonium
> citrate should they wish to experiment (the cheapest and most light sensitive
> combination may well be ferric chloride with oxalic acid). It also notes that
> the green ferric ammonium citrate gives much more sensitive papers with purer
> whites than the brown salt.
We talked about green vs. brown a while back.
> The formula I've used with the green compound uses:
>
> A: Ferric ammonium citrate, 36 g dissolved to give 100ml solution.
> B: Potassium ferricyanide 16 g dissolved to give 100ml solution.
>
> Mix equal volumes. I've normally kept these separate as they keep better.
You remind me that I should have mixed my "Plain Old" formula at greater
strength, as you have, to make a fair comparison with the "New." I suppose
I'll have to try a batch that way, tho so far I get, as ever, excellent
D-max & do not anticipate much difference with "the new." I'll add,
however, that I find storage in one container (for whatever reason one
should wish to save a bottle) makes no difference in results up to a
month, after which prints show some veiling, tho perhaps the weaker
solution makes things easier there.
> As with Terry, I've experienced few difficulties in getting good results from
> the blue-print. This surprises me slightly as both of us live in an area with
> hard, slightly alkaline water which might have been expected to give problems.
My hunch so far is that the paper is a bigger variable than the wash water
-- we don't know what paper the offending inferior prints were on, for the
most part, or what paper you used...
> Some papers I've found to produce an image that looks fine when wet, but on
> drying is disappointingly dull - maybe this is a sizing problem? Or perhaps
> quicker drying after coating would help.
>
If by "quicker dry" you contemplate heat, I'd do that with great
discretion. My tests show it is a potentially lethal variable. I find,
however, that a plain electric fan (small size, about $9 at Woolworths) in
the area dries any emulsion very promptly, & strongly recommend it for
all occasions. I'll add also that almost all prints (including gum) are
more beautiful wet than dry.
Judy