Re: D-76 to Lc-1

[Richard Knoppow <dickburk@ix.netcom.com>]

At 01:27 PM 08/01/2001 -0600, you wrote:
>bicarbonate - that would be baking soda, correct?
>
>If that's correct I'll try fiddling with dektol and baking soda.  Everyone
>should be able to get Dektol and baking soda :)
>
>Any ideas on how much baking soda should be added to a litre of Dektol to
>make it act like 2:3:5 LC-1 ?
>
>Gord
>
>On Wed, 1 Aug 2001 FotoDave@aol.com wrote:
>
><snip>
>> I first thought about adding bicarbonate to Dektol ...
></snip>
>---------------------------------------------------------
>Gordon J. Holtslander		Dept. of Biology
>holtsg@duke.usask.ca		112 Science Place
>http://duke.usask.ca/~holtsg	University of Saskatchewan
>Tel (306) 966-4433		Saskatoon, Saskatchewan
>Fax (306) 966-4461		Canada  S7N 5E2
>---------------------------------------------------------
>
  Bicarbonate of soda is baking soda like the familiar Arm and Hammer
stuff.  Baking powder has bicarbonate in it but usually also has other
ingredients.
  Probably sodium bisulfite is a better choice for lowering the pH. 
  For Dektol one can simply use less carbonate. An alternative formula is
Kodak D-52, the basis of the late, lamented Selectol. I will post the
formulas below for comparison. 
  Kodak also makes an interesting print developer called Ektonol which does
not contain carbonate. The MSDS shows Borax and hydroxide. These combine to
form Kodalk, or sodium metaborate. I can't tell from the MSDS whether the
proportions are the same as for metaborate. I've never seen a published
formula for a metaborate paper developer but one could experiment.
metaborate has a pH midway between borax and carbonate. 
  Kodak also has a forumla for D-76 made with metaborate. The amount is
equal to the amount of borax but its probably somewhat more active. I think
this was an early attempt to deal with the pH rise of D-76 since metaborate
is a better buffer than borax. The borax-boric acid mixture, however, is a
still better buffer and can be adjusted over a wide range of pH. 
  For some reason which I've forgotten bicarbonate is rarely used in
photographic formulas. It may simply be that it becomes something else in
solution with the release of a lot of carbon dioxide. We have some real
chemists on this list who could tell us more. 
  I forgot to post the citation for the Carlton and Crabtree paper. Its
hard to find. 
"Some Properties of Fine-Grain Developers for Motion Picture Film",
H.C.Carlton and J.I.Crabtree, _Transactions of the Society of Motion
Picture Engineers_ Vol.XIII, No.38, 1929
  If you go looking for this it may be held with the _Journal of the SMPTE_
which was its successor. The _Transactions_ were published quarterly from
the inception of the SMPE (1915?, 1919?) until 1930 when it was superceded
by the _Journal_ on a monthly basis. 
  There is a second interesting article in this same issue: "Borax
Developer Characteristics" H.W.Moyse and D.R.White (of DuPont) loc.cit.
p.445 ff.

  For reference:
Kodak D-72 (Dektol)

Water (at 125F or 52C)				500.0 ml
Metol							  3.0 grams
Sodium Sulfite, dessicated			 45.0 grams
Hydroquinone					 12.0 grams
Sodium Carbonate, monohydrated		 80.0 grams
Potassium Bromide					  2.0 grams
Water to make 					  1.0 liter

Dilute 1:2 for use

Kodak D-52 (Selectol)

Water (at 125F or 52C)				500.0 ml
Metol							  1.5 grams
Sodium Sulfite, dessicated			 22.5 grams
Hydroquinone					  6.0 grams
Sodium Carbonate, monohydrated		 17.0 grams
Potassium Bromide					  1.5 grams
Water to make					  1.0 liter
Dilute 1:1 for use. 

An example of a film developer employing sodium bisulfite is 
Kodak D-61a
Water (at 125F or 52C)				500.0 ml
Metol							  3.0 grams
Sodium Sulfite, dessicated			 90.0 grams
Sodium Bisulfite					  2.0 grams
Hydroquinone					  6.0 grams
Sodium Carbonate, monohydrated		 14.0 grams
Potassium Bromide					  2.0 grams
Water to make 					  1.0 liter

The old instructions (c.1947) are to dilute 1:1 for tray use and 1:3 for
tank use. 
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com