COLOUR NEGATIVE PAPER

By Brian Asquith (Area 11.)

With the introduction of Rapid Access Paper people who do their own processing and make up their own brews have been dismayed
to find  the formulae they are used to no longer work. I have been fortunate to be in touch with Tom Arnos, who used to supply 
chemicals. Between us we have come up with a working formulae for EP2 and RA4 Colour Negative paper. I can say without reservation
they work well. The RA4  is so quick you can now have a test strip within 2« minutes, developed, bleached & fixed.

 I do my processing in open dishes, using a piece of hardboard covered with plastic (to protect from condensation) to cover the dish
 (developer) during development. I have a large dish heater which was essential for EP2, but not as  important with RA4, because of 
rapid processing at low temperature. I work under a dark green safe light, hense cover for developing dish. Quick transfer into Stop 
bath, ½ minute. You can go from that straight into Bleach/fix but I have running water so I give a quick rinse then into B.F. Once after
 Stop bath lights could be turned on but I find no difficulty working by safe light. Dry test strips by your heater, asses for 
exposure/colour casts.

 My enlarger, an Optomus, gives me 16" x 12" from 15" x 2¬" negs.  30 secs F.8. With filtration around 60M, 65Y, a bit longer for
 35mm, all 120`s are  Fuji 400 film.

 So you can see, it is basic stuff. No drum or tank. It works quickly and I have to be really clumsy to finish up with any stains, 
scratches etc. Chemicals show no sign of going `off`. Two Litres processed 10 16" x 12" without change in quality, from first to last. 
I don`t know at this stage what the capacity would be or the keeping qualities once used, with RA4 but with EP2 chemicals just seem 
to go on and on. The bleach keeps for ever some being used over a 2 year period. Can be discarded when bleaching is taking too 
long or giving a orange effect.

FOR EP2 PAPER

P A P E R  D E V E L O P E R        1 L I T R E      p H  1 0. 0 8

    Benzyl Alcohol                                                         14. 5 ml
    Or Solution made up                                                     30%
    Ethelene Glycol                                                             30 cc
   10% Benzyl alcohol

    Potassium Carbonate or Sod Carbonate          32 or 25 gms
    Potassium Sulphite or Sod Sulphite                             2 gms
    Potassium Bromide  10% Sol.                                           5 cc
    Hydroxylamine Sulphate                                             3.4 gms
    Calgon                                                                               2 gms
    Trace of Wetting Agent  CD3                                       5 gms

STOP BATH

    5% Acetate Acid                                      1 Litre

BLEACH.FIX

    EDTA Fe (iron salt) Na                                   50 gms
    Potassium Metabisulphite                             25 gms
    Ammonium Thiosulphite                               100 gms
    Potassium Iodide                                                  1 gm
    Water to                                                              1 Litre

TIMES 35C

    Developer                                            1½ mns.
    Stop                                                          ½ mn.
    Bleach                                                2 - 3 mns.

FOR RA PAPERS

D E V E L O P E R                                       pH 1 0 . 6.

    Glycerine                                                 50 mls
    Hydroxylamine Sulphate                         1 gm
    Sodium Carbonate                                25 gms
    CD 4                                                          5 gms
    A drop - Wetting Agent/ 1 litre

NOTES.   I have been told that 20 gms Sodium Bicarbonate and 9.5 gms Sodium Hydroxide gives better keeping properties but haven`t
  tried it yet. 40 gms of Potassium Carbonate can be used instead of Sodium Carbonate.

Ethylene Glycol can be used instead of Glycerine.  probably 100mls. pH 10.6 spot on using above formulae

STOP BATH

                                                         5% Acetic Acid

BLEACH/FIX                                              pH 7.95

    Ammonium Thiosulphate                        90 gms
    Ammonia                                                        6 cc
    Potassium Iodide                                    0.5 gms
    EDTA Na2 or 4                                           1 gm
    EDTA Fe Na (Iron Bleach)                     35 gms
    Water to                                                    1 Litre

NOTE   pH is spot on using above Ammonia at 6cc.

    DEVELOPING TIMES             STOP                BLEACH 25C

    25C  -  40 secs.           30 secs.                1½ mns.
    24C  -  45 secs.
    23C  -  50 secs.
    22C  -  60 secs.
    21C  -  70 secs.
    20C  -  75 secs.

Strathpeffer My Heil'n Hame

Editorial

CRCMain