D-76

wrote:

With 1:1 D76 one shot,
what's the max number of rolls, say Ilford Delta 100
(or your favorite BW film), can be fully developed in 1000
ml in a JOBO processor? thanks, alex


There's at least 8 rolls of chemistry in 1 liter of stock.
12 rolls I think a more reasonable number and that with
very exposed high speed film. 16 rolls wouldn't surprise me
using slower normally exposed film. Sky's the limit for
slow unexposed film.
I'm quite sure Kodak and others with their one-size-fits-all
recommendations have allowed a Great deal of margin.
Split that 1 liter stock as fits your needs. The more dilute
the more time. I think 1:3 perhaps a practicle limit. I advise
dilution from stock to working strength at time of use. Keep
stock in small bottles. Should last a long time. Dan

Jon Rogers wrote:

I've tried stainless steel tanks and couldn't get on with them, so I now
use Paterson, which stipulates 290ml/10oz per 35mm roll, and 200ml/17.5oz
per 120 roll.

I mix 1 litre of D-76, and store it in four 250ml bottles. When I come
to use it, I simply add 250ml of water, and use as much as I need (i.e.
300ml for a 35mm film (discarding 200ml), or the whole 500ml for a roll film.

If I want to develop multiple films, I'll use 600ml for two 35mm films,
and discard 400ml.

I guess from now on, I'll just put the the whole 1l in the tank,
effectively using 8.5 oz per film, and this issue won't arise.

I haven't used Paterson tanks. But my guess is that you won't
be able to get a full 1 liter in a tank that holds only two reels.
The amount of solution you use should be determined by
what the tank holds. Then, if that amount is less than the
(450ml of 1:1)/1 roll capacity, you can extend the developing time.

The stock solution keeps OK in a full bottle, and for a little
while in a half full bottle, so you don't need to immediately
discard the part you don't use when diluting down to 1:1.
I keep it in plastic drink bottles that can be squeezed to get
the air out (I label and store them so nobody drinks it,
of course.)

On 13 Jan 2006 15:44:45 -0800,
" wrote:

That makes 4 rolls. And if undiluted D76 (1:0) is used, does it mean
it can do 8 rolls in 1000 ml?


January 16, 2006, from Lloyd Erlick,

Kodak rates the capacity of D76 at 16 rolls
of film per gallon. It makes no difference
how it is diluted or applied, the gallon will
still develop 16 rolls. (For ease of
calculating mentally, it is probably
acceptable to say 4 liters of D76 will be
equivalent to a gallon.)

The recommendation of Kodak is very likely a
conservative one, so it could be possible to
develop more than 16 rolls per gallon. How
many more would depend on individual
variables such as how much exposure one's
rolls have recieved.

regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email:
net: www.heylloyd.com
________________________________
--

Richard Knoppow wrote:

There is still a data sheet for D-76 on the Kodak web
site. Search for J-78
At 1:1 the capacity is given as one 80 square inch roll
in 16 ounces or two in one liter. If a single roll of 36
exposure 35mm film (80 square inches) is developed in an 8
ounce tank or two in a 16 ounce tank extend the recommended
development time by 10%.


Well what's it going to be, one roll or two in 16 ounces?
Or did you mean to say, extend the time if two rolls are in
that 16 ounces.
I think an additional 30 to 40% increase in time would see
that 16 rolls I mentioned well done from 1 liter of stock.
16 rolls of 120 at 400 ml per roll equals 4.8 liters of working
strength. That's a 1:4 dilution. Say Plus X, 16 minutes, invert
twice each two minutes.
I don't use off the shelf D-76 so can not test. An easy
enough thing to do though. Why throw good chemistry
down the drain. Test it. Dan

An error in that dilution I'm sure a few spotted.
At 375 ml per roll 16 rolls would need a 1:5
dilution.

As Mr. Erlick has reasserted, cut it any way
you like; so much chemistry = so many rolls.
I think the 4 roll per liter stock pre-planned
obsolescence. Dan