As regards not using (para)formaldehyde for lithographic
film development I have tacked to the corkboard in the
darkroom:
> Kodak D-8
> Richard Knoppow provided also, this formula which dispenses
> with paraformaldehyde. Richard's formula is as follows:
>
> Water (90 degrees F) 750 ml 7 oz
> Sodium Sulfite (anh) 90 gm 3 tsp
> Hydroquinone 45 gm 3 tsp
>
> Let cool before adding
>
> Sodium Hydroxide 38 gm 1.5 tsp
> Potassium Bromide 30 gm 2 oz 10% soln
> Water to make 1 litre 8 oz
>
> Richard notes that the solution should be stirred thoroughly
> before use. He also suggests that a less alkaline version
> which will give nearly as much contrast can be obtained
> by reducing the amount of Hydroxide to 28 grams per liter.
> He also wisely notes that one should be very careful mixing
> the hydroxide as it produces a lot of heat going into solution
> and can cause boiling and splattering. Hydroxide should only
> be added to COLD solutions.
>
> To Use with Films:
> Mix 2 parts stock solution and 1 part water.
I added the 8 oz make-up - about right for a few sheets of
4x5 in a tray.
The paper on the corkboard doesn't list its provenance,
but it appears here:
http://members.iinet.net.au/~forbes/lithdev.html
with the additional comment:
> To Use for Lith Printing:
> I'm going to experiment with this developer and
> post my preferred dilutions for lith printing.
> Until I do, I suggest that you consult Tim Rudman's
> book for ideas on diluting it for use in printing.
I use this stuff with lith film and it works well, not as
dramatic and dense as Kodalith A/B but certainly workable.
The _original_ formula was obviously:
Water (90 degrees F) 24 oz
Sodium Sulfite (anh) 3 oz avdp
Hydroquinone 1.5 oz avdp
Sodium Hydroxide 1 oz avdp
Potassium Bromide 1 oz avdp
Water to make 1 quart
Formulae with 85.1 gm of this and 38.35 gm of that give the
impression that titrations of great precision were used
in determining the optimum amounts. The amounts only
look funny because they got converted to metric, rounded
(or not) and then tweaked with 'and extra 10 ml or so'
yielding numbers like 38.35 ml.
The quantities used when the formula was developed are
obviously a jigger or this, a splash of that and a
teaspoon of the other. When making it up there is
no need to be any more precise.
==
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121
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