Re: recipe for fine-line developer?

Well, it looks like I might have forever lost my fine-line developer formula
due to a computer crash a few years ago, but I found a message in 2000 that
I downloaded. It contains different formulae for lith films. Hope this is
helpful in some way.

Dave S
PS: Credit goes to Michael Gudzinowics

Subject: Re: Lith Developer formulae... where?
From: bg174@FreeNet.Carleton.CA (Michael Gudzinowicz)
Date: 12/7/00 4:19 PM Pacific Standard Time
Message-id: <90p9eq$np2$1@freenet9.carleton.ca>

Klaus Schmaranz <kschmar@iicm.edu> wrote:

>Is there any place where I can find formulae for lith developers? At
>the moment I'm using Kodalith and I'm quite pleased with the results
>lith-print wise, but I'd really like to mix it myself, as I do with
>the rest of my chemistry.

Although the lith developers are often thought of as simply high contrast
developers, they have a unique property. In the absence of sulfite, the
hydroquinone dianion reduces silver and is oxidized to the semiquinone
free radical. The semiquinone is a more powerful developing agent than
hydroquinone, and it reduces another silver atom and is converted to
quinone. Then quinone reacts with hydroquinone to form two semiquinone
molecules. They reduce silver, generating two quinones. They react with
hydroquinone, forming four semiquinone molecules. The rounds of reactions
result in an exponential increase in semiquinone concentration doubling
each time. The addition of sulfite will stop those reactions, since it
reacts with the semiquinone and quinone removing the possibility of
reaction with hydroquinone to generate more semiquinone.

The semiquinone is generated in the emulsion and remains there with a very
short diffusion path. Development starts with grains which have multiple
centers. The semiquinone concentration rises as those grains are reduced,
and then neighboring grains are developed which might have just one center.
As the concentration rises a bit more, development spreads explosively
(exponential).

What one sees is that development starts slowly in well exposed areas of
the film. If a step tablet were used for the exposure, a faint image
appears in the well exposed areas. Eventually the developed area reaches a
critical density and semiquinone concentration, and then development takes
off, and quickly goes to completion in that step. Then as development
proceeds, the next step develops fully.

Essentially one has a two phase development. First the formation of a
faint image, then rapid completion in areas receiving the more exposure.
he results is a film with very little density in areas with little
exposure, and an extremely dense image in areas with a bit more exposure.
As expected, the contrast increases with development to a maximum after 1
to 3 minutes, and then decreases as the low value faint images are further
developed.

Unlike developers with moderate sulfite concentrations, development is
restricted to the grain and filaments are not formed. If free sulfite is
added (20 g/l), filaments are formed and neighboring grains are rapidly
developed. There is no lag phase and significant semiquinone
concentrations are not generated. The developer acts like a typical MQ or
PQ high contrast developer.

Lith developers are fairly simple mixtures. Hydroquinone is the developing
agent, usually present in a concentration around 20 g/l. The free sulfite
level must be very low - less than 2 g/l. Since the developer will oxidize
quickly, sulfite in the form of an addition product with formaldehyde is
frequently used, or formaldehyde, paraformaldehyde or acetone are added to
tie
up free sulfite. The anti-oxidant properties are retained. The formaldehyde
adduct with sulfite is 1:1, and about 3% of the sulfite and formaldehyde are
free in solution when they are dissolved in equimolar parts. Acetaldehyde,
acetone and other ketones act in the same way, but I don't know where the
equilibrium lies.

               __ H _
CH2O + H+ + SO3 <-> HOCOSO2
                           H
      3% 97%

The third component is a base, usually carbonate or mixtures of carbonate,
hydroxide or borates. The pH is frequently adjusted to a value around 10.

Since formaldehyde, its polymerized form paraformalsehyde and addition
products such as the bisulfites are carcinogenic, they should be used with
very good ventilation - preferably in a fume hood.

Rather than using paraformaldehyde, I'd suggest that you use acetone.
The monomer molecular weight of paraformaldehyde is 30, and that
of acetone is 58.08 with a density of 0.788. Therefore, for each gram of
paraformaldehyde used in a formula, substitute 58/(30 * 0.788)= 2.20 ml
of acetone. So for 37.5 g paraformaldehyde, you'd use 82.5 ml acetone.
These it with scrap film, and add more acetone if the lith effect doe not
occur due to an excess of free sulfite.

Two solution D-85:

Part A:
Water, 125 F 500.0 ml
Sodium Sulfite 36.5 g
Boric Acid, crystals 9.4 g
Hydroquinone 28 g
Potassium Bromide 2 g
WTM 1 L

Part B:
Water, 90 F 500.0 ml
Sodium Bisulfite 11 g
Sodium Sulfite 1 g
Paraformaldehyde 37.5 g
WTM 1 L

For use, mix 4 parts A with 1 part B.

I gave the formulation for two solution D-85 since the
single solution developer isn't very stable. The single
solution formula is:

Kodak D-85 (single solution - not very stable)

Water, not over 90F (32C) 500.0 ml
Sodium Sulfite, desiccated 30.0 gm
Paraformaldehyde 7.5 gm
Sodium Bisulfite 2.2 gm
Boric Acid, Crystals 7.5 gm
Hydroquinone 22.5 gm
Potassium Bromide 1.6 gm
Water to make 1.0 liter

Undiluted with a development time of 1.5 to 2.25 min.

Some other developers are:

Packo Lith Developer

Water, not over 90F (32C) 500.0 ml
Sodium Sulfite, desiccated 3 gm
Sodium formaldehyde bisulfite 25 gm
Hydroquinone 12 gm
Sodium Bromide 2.6 gm
Sodium carbonate monohydrate 23 gm
Ascorbic acid 5 gm
Water to make 1.0 liter

Undiluted with a development time of 2 min.

DuPont D-7

Water, not over 90F (32C) 500.0 ml
Sodium Sulfite, desiccated 60.0 gm
Paraformaldehyde 15 gm
Sodium Bisulfite 5 gm
Boric Acid, Crystals 15 gm
Hydroquinone 45 gm
Potassium Bromide 3 gm
Water to make 1.0 liter

Diluted 1+1 with a development time of 2 min.

Stability has been a problem with lith developers, and most
only have a working life of 2 hours or so. Ascorbate extends life
by a small amount, but interferes with activity .By using metaborate
as the base, the open tray life of the following developer
was extended to 8 hours (Welliver & Krizka).

Welliver & Krizka Lith Developer

Hydroquinone 15 g
Sodium formaldehyde bisulfite 50 g
Sodium carbonate 20 g
Sodium metaborate 20 g
Potassium bromide 1.5 g
Water to make 1 L

Another approach used acetonitrile as an antioxidant to improve
the long term storage of the developers in closed containers.

Sodium carbonate monohydrate 50 g
Formaldehyde sodium bisulfite 45 g
Potassium bromide 2 g
Hydroquinone 18 g
Sodium sulfite 2 g
Acetonitrile 10 g (ml ?)
Water to make 1 L

Film developed 2.75 min @ 20C.

More Two-Solution Lith Developers

                       Unit of Du Pont Ansco Chemco
Ingredient Measurement 15-D 79b Dev
Solution A

Water (1250F or 520C) ml 500.0 750.0 500.0

Hydroquinone gram 45.0 90.0 135.0
Sodium sulfite gram 30.0 120.0 -
(anhydrous)
Sulfuric acid ml 4.0 - -
Boric acid gram - 30.0 -
(crystals)
Potassium bromide gram - 6.0 -
Potassium formaldehyde gram - - 110.0
bisulfite monohydrate
Diethylene glycol ml - - 118.0
Ethylenediamine gram - - 0.26
tetraacetic acid
Potassium hydroxide ml - - 2.8
(45% w/v in water)
Cold water to make liter 1.0 3.0 1.0

Solution B

Water (1250F or 520C) ml 500.0 750.0 750.0

Sodium carbonate gram 30.0 - -
(anhydrous)
Potassium carbonate gram 90.0 - -
Sodium hydroxide gram - - 9.5
Potassium bromide gram 8.3 - 1.57
Sodium sulfite gram 90.0 1.0 -
(desiccated)
Paraformaldehyde gram - 30.0 -
Potassium metabisulfite gram - 10.5 -
Potassium formaldehyde gram - - 63.0
bisulfite monohydrate
Boric acid gram - - 13.5
Cold water to make liter 1.0 1.0 1.0

Dilutions 1:1 1:1 1:1 + 4 parts
water
Development time 68 F 4-5 min 2-3 min ?
(constant agitation)
Received on Wed Oct 6 09:23:55 2004