Film curves vs amount of developer solution

[Jeff_4536]

Typically I develop my 4x5 negatives in a jobo 3010 drum, rolling on a Beser print roller base.

I have not done much experimentation in developing times to affect contrast, but am realizing that many scenes I photograph would benefit.

Typically I use 50ml of solution per negative (500ml in my 10 negative drum)- my understanding is that at least 50ml of solution per neg will not become exhausted.

My question:

If I only have, say 5 negatives, or even 1 or 2, in the drum, and use the same volume of chemistry (500ml), will my contrast curves really change appreciably?

I could understand that they would if I was using less than 50ml per negative, but will using more than that amount per negative reallly change things? If so, why?

The reason I ask is sometimes I might only want to do one or two negatives at an non normal development time. If I only used the 50ml of solution for two negatives, it seems to me that, in the large drum, the negatives would not be in contact w/ the small amount of solution for as long a time, as the drum rolls. This would, in my mind, have an impact on the contrast curve.

Thoughts?

[Nick_3536]

Unless you're exhausting the developer normally I don't see how too much developer would matter.

[sanking]

"If I only have, say 5 negatives, or even 1 or 2, in the drum, and use the same volume of chemistry (500ml), will my contrast curves really change appreciably? "

It depends on the developer but in your case I suspect there would be some difference in the curves, especially if the film is being developed for a N+ condition. You are already using a very small amount of solution per 4X5 sheet so I expect that you are experiencing some developer exhaustion when developing 10 sheets in 500 ml of solution, especially if using a very dilute compensating developer. As a general rule I would recommend a minimum of 100 ml of solution per twenty square inches of film with these type of developers.

I am therefore inclined to believe that developing fewer sheets in the same amount of solution is likely to result in an increase in contrast, but exactly how much would depend on the type of developer.

[Jeff_4536]

That is what I thought, but apparantly some people feel otherwise. If anyone has already done some testing in this regard, I'd like to hear your comments. You'll save me a night of running tests and using film and checking densities to find out!

[ronald moravec]

As long as there is 4 oz of stock per 80 sq in and enough total volumn to cover the negative, density will remain unchanged.

[rich silha]

in my photo lab i use 700mls in my jobo 3010 tanks no mater how many sheets i run.
no variation from neg to neg.

[Chris Gittins]

>Typically I use 50ml of solution per negative (500ml in my 10 negative drum)- my understanding is that at least 50ml of solution per neg will not become exhausted.

The amount of stock required per square inch is going to vary from developer to developer. I believe the recommendation is 2 oz. (60 ml) per 4x5 sheet for D-76. I only use about 25 ml of DD-X per sheet and haven't noticed any problems with exhaustion.

Chris

[Jeff_4536]

It is not so much that I am not sure how much solution is "normal" per 4x5 negative- I have pretty much concluded that 5ooml is sufficient for 10 4x5 negatives.

I am hoping that contrast curves would remail the same, if I have only 5 4x5 negs, or 2 4x5 negatives, in the same 500ml solution in the tank.

In other words, I wouldn't want to only put 100ml of solution in that large drum for only two negatives. Most of the duration of a revolution of the drum would take place without the negative in the solution at all, I would imagine!

Thanks for all your responses!

[paulr]

I was always too lazy to do any meaningful tests, so I deal with this issue by saving my scrap film. Any sheets that I've tossed for any reason before development. Since these always have way more exposure than any normal neg (and so will exhaust more developer than a normal neg) I consider each one to be equal three regular negs. My drum holds 12 sheets, so if I need to run a batch with only six, I'll process those six along with two scrap sheets.

I don't know exactly how accurate this is, but my eyes have never been able to see a difference between negs developed in full or partial batches.

[bob carnie]

At our lab , we no longer do single test rolls or sheets , to then go onto full runs , there always is a difference, I believe based on the added film surface exhausting the chemicals faster in a full run.We try to balance full runs to chemicals each time