When the manufacturer has no idea ...

[swmcl]

Without offense to too many ... goodness me what a mess.

I'm reading a pdf that seems to be written by:

Acufine Chemicals
701 Corporate Woods Parkway
Vernon Hills, IL 60061
847-821-5429

I'll see if I can attach it to this post.

In the Acufine replenisher section it states in bold letters the following:

Replenishment: Acufine replenisher should be
added and stirred into the developer after each
batch of film has been processed. Average
replenishment is at the rate of 1/2 fluid ounce per
80 square inches of film ( one roll of 36 exposure
35mm, or 1 roll of 120 or four 4x5 sheet film ).
Replenishment can be continued until a volume
equal to the volume of the original developer has
been added. Without replenishment, four rolls
of film may be developed at normal times.
Increase the developing times by 2% for each
additional roll. Develop no more than 16 rolls
per quart in this manner.

So apart from finding out what fluid ounces were ...

I'm interested in the last section. Four rolls of what can be developed at normal times ? (35 or 120?)
Exactly how much fluid is this developer using per sq inch of film ? If I have a smaller Jobo and put just enough fluid in there to cover the film does the above instruction mean I can do four rolls in such a manner ? If however, I develop a roll in plenty of developer and then tip the developer back into the main gallon container then I assume the 2% bit is discounted. If I were to carry on like this then I'd put the replenisher in after what, 16 'rolls' ??

What a mess.

I'm also assuming that a number of US companies are still not required to use SI units ? I thought ounces were a measure of weight not volume ! And then there's the UK gallon vs the US gallon...

Thank goodness for the French and their SI units eh !

Sorry for the vent but ...

[Leigh]

Wow. You really need to learn photographic terminology.

You would likely learn more with less noise if you simply asked a question, rather than ranting about
a supposed error on an instruction sheet that's been in use longer than you've been alive.

The instructions are absolutely clear and unambiguous.

A "roll" is defined as any combination of film that can be proofed on a single 8x10 sheet of paper.

It equals 80 square inches nominally.

So a "roll" can be a single 8x10 sheet, four 4x5 sheets, one 36-exposure roll of 35mm film, one roll of 120 film, or any other combination that fits on the paper, as was stated in the quoted instructions.

- Leigh

[Vaughn]

One fluid oz is about 30ml. (one US fluid oz = 0.0295 liters)

What is the minimum amount of fluid required to use the Jobo? Usually that is marked on the drum. Most folks using Jobos do one-shot (use and toss) without replenishing, of course.

[ic-racer]

You must be posting with some sort of a computer connected to the internet, no? Type "quart to millileter" in the Google search screen, it has all the conversion. A quart is a little less than a liter, so 1 roll in just less than 250ml. (One 515 square cm roll per 236.5ml)

[swmcl]

Sorry for the rant but I am struggling to get containers with those measures on them. I'm guessing at in-between markings.

I see that I may be misunderstood with regards the roll. It makes a difference in that a 35mm roll can be developed in a rather small amount of fluid and a 120 roll in more fluid yet still there be the same-ish surface of film.

What I'll do is put the developer back into the main tub each time and replenish that from time to time.

It would still be nice for a manufacturer to not sit on their laurels and publish data with other customers and continents (the rest of the world nearly) in mind. That would be considerate (professional) and less myopic. Grrr!

Enough!

[Vaughn]

Just to be sure you are on the right page -- a 36exp roll of 35mm film takes the same amount of developer as one roll of 120, which is the same amount needed for four 4x5's, two 5x7's or one 8x10. All are 80 square inches of film (well, the two 5x7's are only 70 sq. inches).

If you want consistent results, you will need to replenish in a consistent manner and not just 'from time to time'.

Best of luck!

[Leigh]

As a point of clarification...

When using rotary tube processing, the amount of developer required may exceed the amount dictated by the surface area due to the thickness of the film on the spiral reel. The developer must be deep enough to cover the inner-most spiral with the tube on its side.

Replenishment is always based on the number of "rolls" developed, normalized to an 8x10 sheet as previously described. The actual amount of developer in the tank is irrelevant.

As Vaughn said, your replenishment regimen must be absolutely consistent if you expect consistent results.

With the exception of Diafine, I use all developers as one-shot to avoid the replenishment problem.

- Leigh