Re: [Rollei] RODINAL RULES

[Richard Knoppow <dickburk >]

At 04:41 PM 09/12/2001 -0700, you wrote:
>Mac
>
>I'm certain that Richard Knoppow can
>report on the chemical validity of Mac's
>statement.
  Monobath processing is quite practical and, according to Grant Haist, has
some important advantages over conventional processing. In his book on
monobaths [1] he shows improved acutance and grain characteristics in
comparison with three-step processing. 
  A sample of a monobath is given below. This solution is optimized for use
with Kodak Verichrome Pan. 

Grant Haist MM-1 Monobath
Water						750.0 ml
Sodium Sulfite, desiccated		 50.0 grams
Phenidone					  4.0 grams
Hydroquinone				 12.0 grams
Sodium Hydroxide				  4.0 grams
Sodium Thiosulfate, pentahydrate	110.0 grams
Glutaraldehyde (25% in water)		  8.0 ml
Water to make				  1.0 liter

  He gives Distillation Products Co. of Rochester N.Y. as a source for
Glutaraldehyde, 25% aqueous solution, Eastman Organic Chemical No. P 8648,
but I don't know if this is still a valid source.
  The following instructions for mixing should be followed:

"Add the monobath ingredients in the order listed in the formula. After the
Phenidone has been added to the solution, it will be noticed that this
compound does not dissolve rapidly. Weigh out the required amount of
Hydroquinone but add only a pinch of this amount to the solution. the pink
color of the solution will disappear. Set the reminder of the Hydroquinone
aside. then add the sodium hydroxide. The Phenidone will dissolve
completely. Then add the Sodium Hydroxide. Then add the Hydroquinone and
the rest of he ingredients in the order listed. the pinch of Hydroquinone
helps to  prevent oxidation of the Phenidone when the alkali is added. The
higher alkalinity achieved by this technique insures solution of the
Phenidone before the alkalinity of the solution 8is reduced by the
remaining amount of the Hydroquinone. this method of dissolving the
Phenidone may also be used with other formulations containing this
slow-to-dissolve compound." 

  He says this formula was "compounded to work with Verichrome Pan and
deliver contrast and speed nearly identical to conventional processing with
D-76. Other films will vary. Plus-X Pan Professional and Tri-X Pan films,
120 size show a large speed and contrast increase but Panatomic-X looses
speed and contrast."

  For Verichrome Pan the procedure is to develop for 7 minutes @ 75F.
Agitate 5 seconds initially and five seconds at one minute intervals
afterward. 
  Film can be treated in a wash aid and washed as in normal processing. 
  Haist has a table of suggested modifications of the formula for various
Kodak films. 
  Those interested in trying it should attempt to obtain a copy of the book
from the library. 
  Haist also has more info in his large book on processing chemistry [2]. 
    The Glutaraldehyde is a hardening agent to prevent reticulation of the
emulsion due to the rather high pH of the solution. It might not be
necessary for some modern films but is for Verichrome Pan. 

1, _Monobath Manual_ Grant Haist, 1966, New York, Morgan & Morgan Inc. (Out
of print)

2, _Modern Photographic Processing, Grant Haist, (in two volumes) 1979,
Wiley Interscience Books, Reprinted 2000, The Haist Press, Box 805, Okemos,
MI 48805
ISBN (set) 0-471-04286-2
- ----
Richard Knoppow
Los Angeles,Ca.
dickburk  

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