[pure-silver] Re: Ilford developers
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: "Pure-Silver Free" <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 14 Sep 2007 03:08:42 -0700
----- Original Message -----
From: "titrisol" <titrisol@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, September 13, 2007 11:56 PM
Subject: [pure-silver] Re: Ilford developers
Since it was stated that the difference betweeen D76 and
ID-11 has only some restrainer added, I guess it should.
Plus the "ol'brown" syndrome should even help further in
the restraining.
According to my notes D76R contains
Metol 2g - Hydroquinone 5g - Sod. Sulphite (anhyd) 100g -
Kodalk (metaborate) 15g - Water to 1 ltr.
Metaborate can be replaced by Borax (decahydrate) 8g -
Boric acid (cryst) 8g
Note: I read your correction before posting this. Your
corrected replenisher formula checks with what I have. Note
that there was a modified formula for use with the Kodalk
version of D-76 which did contain Kodalk in place of Borax.
The difference between the original D-76 and the
packaged variety is that the packaged stuff is buffered. The
MSDS for ID-11 does not show buffering. The original D-76 is
the well known:
Water (at 125F or 52C) 750.0 ml
Metol 2.0 grams
Sodium sulfite, desiccated 100.0 grams
Hydroquinone 5.0 grams
Borax, granulated 2.0 grams
Water to make 1.0 liter
This was found to increase slowly in activity due to a
reaction between the Hydroquinone and sulfite which produces
some Sodium Hydroxide. In 1929 a buffered formula was
offered which has stable activity, to wit:
D-76d
Water (at 125F or 52C) 750.0 ml
Metol 2.0 grams
Sodium sulfite, desiccated 100.0 grams
Hydroquinone 5.0 grams
Borax, granulated 8.0 grams
Boric Acid, crystalline 8.0 grams
Water to make 1.0 liter
This has the same activity as freshly mixed D-76 without the
buffering.
The instructions state that the slight fog of fresh (unused)
developer can be eliminated by adding 0.25 gram/liter of
Potassium Bromide to the above.
No mention is made of using a replenisher but one may
have been used. Kodak literature is sometimes fragmented and
stuff got left out.
Sometime in the mid 1930's, after Kodalk was introduced, a
version of D-76 employing it was published. This is
sometimes listed as DK-76. It is identical to the original
formula but with 2.0 grams of Kodalk (Sodium Metaborate) in
place of the Borax. This was supposed to provide better
buffering but didn't and was not much used.
An older version of the replenisher contains Borax
rather than Metaborate:
D-76R
Water (at 125F or 52C) 750.0 ml
Metol 3.0 grams
Sodium Sulfite, desiccated 100.0 grams
Hydroquinone 7.5 grams
Borax, granular 20.0 grams
Water to make 1.0 liter
There is a note that if the Kodalk version of D-76 is used
that Metaborate should be substituted for the Borax in this
formula.
The method of replenishment was pretty crude at the time
my reference was published (1943). It was simply to top off
the tank (probably a motion picture tank) to keep the level
uniform with the note that some additional developer be
removed occassionaly. Modern replenishment generally
specifies some definite amount of replenisher to be added,
usually one ounce (about 50ml) per 80 square inches of film.
However, some sort of testing should be done at regular
intervals to insure the consistency of the result. Keep in
mind that developer reaction products will accumulate and
the rate of replenishment should really be set up to keep
them constant after the system reaches equilibrium.
Restrainer:
D-76 contains no restrainer but in the same paper
describing the buffered formula test results showing a small
amount of restrainer added to _fresh_ D-76 reduces its fog
level a little. The restrainer used was Potassium Bromide
and the amount is about 0.5 grams per liter. Agfa's version
of D-76, Agfa 17 contains this amount of Bromide and also a
variation of the amounts of other ingredients. According to
research done by Ryuji Suzuki the Agfa formula is closer to
the optimum formula than is Kodak's. However, it isn't
buffered. Probably it could be buffered by using the same
Borax and Boric acid buffer system as used in D-76d.
Agfa 17
Water (at 125F or 52C) 750.0 ml
Metol 1.5 grams
Sodium Sulfite, desiccated 80.0 grams
Hydroquinone 3.0 grams
Borax, granular 3.0 grams
Potassium Bromide 0.5 grams
Water to make 1.0 liter
There is also a replenisher solution for this.
Agfa also offered a Metaborate version which is identical to
the above except the amount of Metaborate is 2.0 grams
rather than the 3.0 grams of Borax.
Again, this has a replenisher formula, also containing
Metaborate in place of Borax.
Almost every film manufacturer had some version of
D-76, sometimes with slight variations. Also, a number of
variations were devised by various motion picture film
laboratories for use in their automatic machines. Typically
these were more diluted than the normal version.
The current developer recommended by Kodak for B&W
motion picture film development D-96, is, again, a variation
of D-76. For comparison here it is:
Kodak D-96 For Motion Picture Negative Film
Water (at 125F or 52C) 750.0 ml
Metol 1.5 grams
Sodium Sulfite, desiccated 75.0 grams
Hydroquinone 1.5 grams
Potassium Bromide, anhydrous 0.4 gram
Borax, decahydrated 4.5 grams
Water to make 1.0 liter
Target pH at 77F or 25C, 8.62 +/- 0.005
Specific gravity at 77F or 25C, 1.069 +/- 0.003
This developer is meant for use in automatic processing
machines at somewhat elevated temperature but will probably
work fine for still film. Again, its not buffered. Probably
the variation in activity is controlled by adjusting the
replenishment. OTOH, the life of the developer in a tank
with a lid is given as only 2 weeks so any rise in pH is
probably negligible.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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