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D76 Chemistry question

D76 can be used at full strength with, for example; Some TriX films, Infrared, most sheet films. So it should be stored at full strength and can be stored in smaller quantities at the 1:1 dilution.
 
Greg Heath said:
What is the difference between using D76 "stock" or using A 1:1 mixture ?

Would they be considered equal ?

Thx

Greg
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Stock developer can be reused and even replenished. The 1:1 dilution is said to provide slightly enhanced sharpness with possibly more noticeable grain.
My main reason for using it diluted 1:1, is better shadow detail and tonality with most slow and medium speed films. Try exposing two rolls of 35mm FP4 Plus at box speed (DX coded) and develop one in stock D-76 for 8 minutes at 20*C and the other in D-76 diluted 1:1 for 11 minutes at 20*C and you will see the difference in the shadows.
Kodak recommend that the diluted developer is used with in 24 hours of mixing and it should be used once only and then discarded.
 
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As a novice with respect to developing b&w I've done a little bit of reading here on Apug and other places on-line. My understanding, and I may be way off-base here, is the 1:1 dilution allows for longer development times without greatly increasing contrast or grain and, I believe, is a way of expanding tonal range. But I set up a wet darkroom for the first time just last week so I would defer to those with more experience in this area.
 
More descriptive question..

This all started when I downloaded:

http://www.digitaltruth.com/devchart.php?doc=mobile



Arista EDU Ultra 400 D-76 1+1 400 10 min 20C


Arista EDU Ultra 400 D-76 stock 400 7-8 min 20C

(7-8 min listed for 35mm) Will/why would this make a difference, if I am developing 120.

I have been using Kodak D76 Whole Bag mixed with 1 gallon of water
(4 liters or so) and a development time between 7 & 8 minutes for 120 and 4x5 sheet film.

So I was wondering what the difference was between the two mixtures.

I'm, assuming "stock" is the whole bag + filling the gallon (4 liters about)
bottle?

Physically...What would a one-to-one mixture be? Pretend you are mixing it for me, tell me how you would do it.
please..
 
1+1 or 1:1 means one part stock d-76 mixed with one part water. For example 250 ml stock d-76 and 250 ml water
 

So the difference in 35 and 120 are often due to differences in film base or formulation. The difference in roll and sheet also is due to differences in agitation tank vs tray. 35 and 130 are most often the same. sheet can be vastly different when done in tray but could be the same if using a tank.

So you mix the stock and put in your gallon jug. Just before you develop you mix 250ml stock and 250 water for a 1-to-1 dilution in a 500ml tank. When done toss it.
 
35mm developing times are often a little shorter than for 120 because 35mm tends to be enlarged greater; minimum development time reduces grain clumping slightly, and this is often important for 35mm because of the bigger enlargement. 120 users can usually stand a slightly denser negative over 35mm because of the lower enlargement ratio; Sheet film can be a little denser than 120 for the same reason.

D-76 is said to "blow out" highlights when used straight; 1:1 dilution helps prevent this (per Film Developing Cookbook). Personally, I have not used D-76 a lot so I can't say from experience, but when I've used D-76 straight, I haven't generally liked the results (this was ages ago).

Charlie
 
Maybe it's a "Man" thing...that I just don't read the instructions.

dances_w_clouds said:
Yes: you were all right I wasn't. I noticed my mistake after my morning coffee and cig. I was doing my measurements to Imperial gallons which is ALMOST 5 liters.
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I have been using D76 in the Stock mode. Being such a newbie, and lack of probably reading the instructions I mistakenly assumed that a "Stock" mixture was the same as a 1+1 mixture.

I also had been using the "Stock" mixture and using it ONCE and then dumping it. I didn't realize that I could use it more than once in the "stock" form. I actually went and pulled up the instructions.

If I Mix the D76 full strength (Stock) then I can make a 1+1 mixture.
1 part stock to 1 part water for a "one time" developer, much like using the Ilford Chemicals normally, and then dump it.

I had always wondered why in my neophyte mind there was a D-76 replenisher. DUH ! I guess it pays to read the directions, and to not assume. If I had heeded that info, I could have saved so much money.

Live and learn...

Greg
 
Greg Heath said:
I have been using Kodak D76 Whole Bag mixed with 1 gallon of water (4 liters or so)...Physically...What would a one-to-one mixture be? Pretend you are mixing it for me, tell me how you would do it.
please..
Click to expand...

I have been following the instructions on the package (Kodak Professional D-76 Developer, CAT 146 4817, for making the stock sol'n. Method is mix contents of 415g bag with 3 litres 50-55 C water until dissolved then top up to 3.8 Litres total vol.(1 U.S. Gallon). This is the stock as I understand it. When making a 1:1 dilution mix equal parts of stock and water which for me, if I'm doing two reels of 120 in a stainless tank, is just about 360::360 ml to cover the two reels of film. I believe these are the methods, and measures, the manufacturer intends.
 
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When making a 1:1 dilution mix equal parts of stock and water which for me, if I'm doing two reels of 120 in a stainless tank, is just about 360::360 ml to cover the two reels of film. I believe these are the methods, and measures, the manufacturer intends.[/QUOTE]

*******
Yup.
 
In the photo community there is mixed understanding regarding ratio ) and +. Some would say that 1:1 would be undiluted, raw, neat, whatever -- stock solution. You would use one part stock D-76 and add nothing to maintain 1:1 (1 to 1). A 1:2 ratio would be using 1 part D-76 and adding an equal amount of water to reach 1:2.

Others will insist 1:1 is equal amounts of stock and water; such as D-76 1:1 is one part D-76 and an equal part of water.

The 1:1 as a ratio has become accepted to mean 1+1.
 

Appears the photo community convention differs from basic lab shorthand as I remeber it. I learned that 1:1 meant equal parts of two different soln's. In any case, the OP's insistence on a description of the methods used is well-taken. When in doubt I revert back to a description of Measures, Materials, Methods, & Procedures to help avoid miscommunication, misunderstandings, and worst of all--the loss of hard-earned exposures. This basic approach has also helped prevent embarassing incompatibilities between spacecraft attempting to dock with each other.
 
Bruce Osgood said:
Others will insist 1:1 is equal amounts of stock and water; such as D-76 1:1 is one part D-76 and an equal part of water.

The 1:1 as a ratio has become accepted to mean 1+1.
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Yes that is exactly what Kodak mean, although they should also use the + symbol as Ilford does to avoid confusion. By the way, 1:0 would be for stock solution.
 
Keith Tapscott. said:
Yes that is exactly what Kodak mean, although they should also use the + symbol as Ilford does to avoid confusion. By the way, 1:0 would be for stock solution.
Click to expand...

Agreed. In discussing ratios: 1 to 1, is 1:1, is equal volumes, is 1 part A and one part b, is 1+1. 1:0 is what it says it is.
 
Bruce Osgood said:
In the photo community there is mixed understanding regarding ratio ) and +. Some would say that 1:1 would be undiluted, raw, neat, whatever -- stock solution.
*******
This is bullwinkle.
Click to expand...
 
 
Greg, D76 as I understand it, was originally developed for deep tank processing using a replenishing system. The replenishing system is quite simple really; you develop a film, and then add something like 20ml of replenisher.

I worked in a place where we had deep tank and roller transport B&W baths with automatic replenishment systems. They were great if you were continuously developing film; say about 10 rolls or sheets an hour day in day out. If you developed 15 rolls/sheets in the first hour of the day, then nothing until late afternoon, the bath will have changed a bit and the next roll/sheet through will be developed to a different strength.

Consistency is what it is all about and one way for the amateur or very small user to remain consistent, is to use one shot processing. This can become a little expensive so many people dilute the developer with equal parts stock solution and water, or as you now know, 1+1. Another dilution often used and quoted is 1+3, another dilution used but hardly ever quoted, is 1+2.

With each different developing strength, you will notice a difference in your film. I prefer stock solution for portraits, especially if using very high contrast lenses. For most general work I prefer 1+1, with some landscape work and trying to get as much apparent sharpness as possible, I use 1+3.

I have been using D76 almost exclusively for about 25 years now for all of the different films I develop, in that time I have come to know and understand pretty much what I will get when I fire the shutter. I do one thing different to you; I mix the developer from raw chemicals, which is something you may wish to think about further down the track.

Doing this allows you to have control in ensuring you always have fresh stock solution in amounts that are compatible with your throughput. For instance, instead of mixing up 3.8 litres of stock solution you can mix up 1 litre or 1.5 litres or any amount deemed necessary for your throughput. The really good part though is that your costs per litre remain constant, you don’t have to juggle the possibility of buying the bigger kit to make it cheaper, then realise you are only able to utilise ½ of the kit before it starts to go off.

To mix your own chemicals is easy, you only require a set of scales, a stirring rod and some washable plastic beakers, and then you’re off. You also require some stock of chemicals!

One last thing, I would suggest that whatever you do, use metric all the way from start to finish.

Mick.
 
Gosh, I love this forum.[/QUOTE]

***********


So do I.
 
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