Just what am I really doing?

[pbromaghin]

When posting photos in the gallery, I say that I'm using D-76 1:1, but that isn't really true. I base my method on this bit from page 2 of the Kodak D-76 Technical Data Sheet, regarding 1:1 processing:

"You can develop one 135-3 roll (80 square inches) in 473 mL (16 ounces) or two rolls together in 946 mL (one quart) of diluted developer. If you process one 135-36 roll in a 237 mL (8-ounce) tank or two 135-36 rolls in a 473 mL (16-ounce) tank, increase the development time by 10 percent..."

My Jobo tank holds 5 35mm, or 6 120 (double stacked), and maximum of 2.1L, so it would never come close to holding that much liquid. Laid on its side for roller processing, it holds about 1100mL Per above, I use about 120mL working developer per roll, which comes to 600 or 720mL normal working solution, plus enough water to fill it to 1100mL. Add the 10% to the time and negs come out just fine.

So the concoction is much more concentrated than normal 1:1, but uses half the D-76. What to call it?

 

[MattKing]

Your terms are shifting back and forth !
When you say "I use about 120mL working developer per roll" is that 120ml stock developer per roll? Or is it 120ml of diluted developer?
That datasheet says that the capacity of stock D-76 is 4 rolls per litre or one roll per 250 ml, without compensation. If you use half that amount of stock per roll (125ml) Kodak recommends a 10 percent increase in time.

 

[pbromaghin]

120mL stock developer. I considered "stock" synonymous with "working", as opposed to "diluted". And yes, I have added 10% time. I don't know where you get this 250 mL thing, nor the liter nor 125. None of them are mentioned anywhere in the document. I say 120 as a rounded up 1/2 of 237.

J78.fm (kodakalaris.com)

 

[MattKing]

I don't know where you get this 250 mL thing, nor the liter nor 125. None of them are mentioned anywhere in the document.

Page 5 - Storage Life and Capacity
Capacity of 4 rolls per litre means 250 ml per roll.

 

[Deleted member 88956]

When posting photos in the gallery, I say that I'm using D-76 1:1, but that isn't really true.

This is how far I went reading this.

 

[koraks]

600 or 720mL normal working solution, plus enough water to fill it to 1100mL

So that makes a dilution of 600:500 to 720:380, which is close to 1:1 ~ 2:1. Why you use different dilutions with apparently the same development time is something only you know, of course. It doesn't make much sense to me, but apparently, you're happy with the result, and that's what counts.

 

[fdonadio]

People should stick to the “+” notation, instead of the colon.

In chemistry, the colon notation is X “parts” of the substance to “Y” parts of solution. So, “1:1” and what we call “stock” are the same.

A 50% solution would be expressed by “1:2”: one part of the substance to two parts solution. This is clearer when expressed as “1+1”: one part substance, plus one equal part of water.”

 

[pbromaghin]

So that makes a dilution of 600:500 to 720:380, which is close to 1:1 ~ 2:1. Why you use different dilutions with apparently the same development time is something only you know, of course. It doesn't make much sense to me, but apparently, you're happy with the result, and that's what counts.

600ml when processing 5 rolls of 35mm, 720ml when processing 6 rolls of 120. I use the same time because, while the strength is different, the amount of developer per roll is the same.

 

[pbromaghin]

Matt King - Thank you for clarifiying it.

 

[pbromaghin]

People should stick to the “+” notation, instead of the colon.

In chemistry, the colon notation is X “parts” of the substance to “Y” parts of solution. So, “1:1” and what we call “stock” are the same.

A 50% solution would be expressed by “1:2”: one part of the substance to two parts solution. This is clearer when expressed as “1+1”: one part substance, plus one equal part of water.”

Wasn't there a long thread on this subject a couple years ago that came to no agreement on 1:1 vs 1+1?

 

[fdonadio]

Wasn't there a long thread on this subject a couple years ago that came to no agreement on 1:1 vs 1+1?

Most threads on APUG/Photrio never come to an agreement!

 

[koraks]

I use the same time because, while the strength is different, the amount of developer per roll is the same.

That would make sense only if development was determined by exhaustion of the developer. This is not the case, and certainly not with d76. App this shows of course is that unless one actually does measurements, negatives can come out "OK" within fairly broad processing margins.

 

[NB23]

I don’t understand.

As a sidenote; using “+” is a better idea.

As a side-sidenote; on photrio there is never an agreement. After countless posts about useless prewashing, people still prewash their films.
Same for stand development.

 

[Sal Santamaura]

...After countless posts about useless prewashing, people still prewash their films...

Perhaps they reached their conclusion about its usefulness from the posts of someone other than you:

https://www.photrio.com/forum/threads/pre-washing-film.139889/page-4#post-1850966​

 

[pbromaghin]

That would make sense only if development was determined by exhaustion of the developer. This is not the case, and certainly not with d76. App this shows of course is that unless one actually does measurements, negatives can come out "OK" within fairly broad processing margins.

Then what would make sense to you with this volume and concentration?

 

[MattKing]

Then what would make sense to you with this volume and concentration?

Assuming you need 1100 ml to cover the reels in either case, use the same dilution - 720 ml stock diluted to 1100 ml.
Your results will be more consistent between the two formats, although both will be vulnerable to developer exhaustion.
To avoid any issues of developer exhaustion you would need to squeeze 1500 ml of stock developer into that tank.
An increase in time helps offset partially the exhaustion potential, but the 10 percent increase in time may not be enough - particularly for the six 120 rolls. Try 12.5 percent for the 35mm rolls and 15 percent for the 120.

 

[koraks]

Then what would make sense to you with this volume and concentration?

Either keep concentration constant or work out the difference in time to adjust for the difference in concentration. The former is easier and less time consuming.

 

[Doremus Scudder]

If your developer is being exhausted somewhat in your regime, it is likely not by that much, or you wouldn't be getting negatives you like. You've compensated for some potential exhaustion with the increase in development time.

Still, you may be getting a bit of compensation, which is simply developer exhaustion at the right point in development to keep the highlights (densest areas) from developing as fully as they would with a larger volume of developer. Many people like the compensation effect and it's a good tool for contrasty scenes. Pyro developers are renowned for this and seem pretty popular.

So, if you like the results and are getting highlights you like, you're just fine. If you find you need to work hard getting contrast and separation in your highlights when printing, then maybe you need to try increasing the amount of stock D-76 per roll and see if that helps.

Best,

Doremus

 

[Vaughn]

Why are we after consensus, or even a percentage of agreement? I can get wrapped in the ego thing as tightly as anyone else, but as long as we can communicate and ask for clarification if needed, then all is cool.

I must say that my mild OCD is not totally comfortable with 1+19. It's an incomplete math(s) equation!

Doremus -- Would there be the noticeable difference in the highlights between holding them back by just time vs the exhaustion of the developer?

 

[pbromaghin]

Question- If I am in danger of developer exhaustion, why is the use of the volume of developer that I am using mentioned favorably in the official Kodak literature, the only difference being that I am using it in a more concentrated form?

 

[Andrew O'Neill]

If you are taking stock solution and adding an equal amount of water to it, then you are developing at 1+1. If you make 600ml of total solution, but only use 500ml of it, it is still 1+1. I was asked this yesterday by a student...

 

[138S]

D-76 1:1

Let me add something...

As explained you say 1:1 to mention the real dilution you used... when you say 1:1 you tell people that film grain is a little coarser and image (perhaps) a little sharper because the develper's dilution decreases the solvent "effect" of sulphite ingredient.

You may use developer "one shot" or you may reuse it.

After processing a roll developer can be more or less destroyed depending on if processed negative is dense or not. If the roll was simply not exposed then no halide will be reduced (only fog) and developer will remain intact. If film was fully exposed then developer will react a lot.

So when reusing developer the perfect correction time is unknown, still you make a correction that will be mostly suitable.

 

[MattKing]

Question- If I am in danger of developer exhaustion, why is the use of the volume of developer that I am using mentioned favorably in the official Kodak literature, the only difference being that I am using it in a more concentrated form?

D-76 works optimally using the capacity recommendations that Kodak provides. However, unlike some other developers, it will work similarly, if not optimally, if you slightly exceed its normal capacity, but compensate by adding more time.
It takes a lot of D-76 to develop a film - more than most other developers. That is a reflection of its relatively low activity.
Originally D-76 was most frequently used in deep tanks and high volume processing lines, with replenishment. In that environment capacity issues were dealt with by adding replenesher, and exhaustion wasn't an issue if that was done properly.

 

[pbromaghin]

My main purpose of this thread, to put a name to what I have been doing, has been answered - I am doing 7+4, one-shot, with 1/2 the usual stock solution, adding 10% compensating time.

From this discussion, I believe I will switch to 2 qts (1qt stock + 1qt water) with constant agitation, and still add the compensating 10% of time. This will be the easiest for me, as the D76 powder mixes up to 1 gallon and I store it in 1qt brown bottles.

Thank you all!

 

[Doremus Scudder]

... I must say that my mild OCD is not totally comfortable with 1+19. It's an incomplete math(s) equation!
Doremus -- Would there be the noticeable difference in the highlights between holding them back by just time vs the exhaustion of the developer?

Vaughn,

I've been cogitating about your question and don't have a real answer. I'm not a real sensitometrist.

Still, in both cases, the development of the highlight densities is arrested, one by developer exhaustion, one by simply ending development. At first glance, these seem like similar, if not the same, things and the effect should be similar as well.

However, in the case of simply using time, the developer is, presumably, at "full strength" through the entire development, meaning it acts fairly aggressively the entire time until development is ended. In the case of exhaustion, the developer loses activity gradually, which should (I surmise) give the resulting curve more of a slope. I don't really know how much difference there would be. Testing and taking readings with a densitometer would tell the tale, but I'm not in a position (or really willing) to do such testing.

Maybe someone here with a densitometer has done some such testing already? Bill Burk? Steven Benskin?

Best,

Doremus