D-76 waiting time after mixing stock

[jensenhallstrom]

Hi, ive seen a thread or two on this subject, some people have explained they havent had any trouble with using their freshly mixed stock d-76 as soln as it cools, others say you have to wait 24 hours after mixing to use. Can i get a legitimate explanation why this 24 hour rule would help the developer in whatever aspect rather than using as soon as it cools? Thanks.

 

[MattKing]

When it is first mixed, D-76 is more active than normal. If you use it immediately, your negatives will be developed more than normal.

After 24 hours, the activity will have stabilized, and thereafter will remain quite consistent for some time, until the developer starts to degrade due to age.

I don't have quantitative information about how much over-development will occur because of using freshly mixed developer.

 

[jensenhallstrom]

When it is first mixed, D-76 is more active than normal. If you use it immediately, your negatives will be developed more than normal.

After 24 hours, the activity will have stabilized, and thereafter will remain quite consistent for some time, until the developer starts to degrade due to age.

I don't have quantitative information about how much over-development will occur because of using freshly mixed developer.

Thank you. That makes sense!

 

[Bill Burk]

One thing I like to do is maintain personal time-contrast index charts of TMY-2 and D-76.

The fluctuation in activity of D-76 over time has been explained and I can accept the explanation.

I would say, that using fresh D-76 while performing calibration lab tests would be a mistake. Just as exposing test wedges immediately before developing would be a mistake. Both of these mistakes would possibly lead you to believe your film speed is higher than you would really achieve in the field.

But I do not believe using fresh D-76 would be harmful in day-to-day developing.

 

[Bill Burk]

MattKing's explanation is about perfect.

 

[tkamiya]

I wait over night before using any developer, not just D76. Reason being when freshly mixed, I always have something floating around and not completely dissolve into water. I'd hate to have them land on my film and create spots of over/under development. I guess I can filter them but I just mix mine the night before so that everything has time to fully dissolve. I don't necessary wait 24 hours. Sometimes, more like 12 hours.

 

[clayne]

D-76, I usually wait overnight as it's not going to cool any faster. XTOL I use immediately.

 

[markbarendt]

I'd say as soon as the powder has fully dissolved and it has cooled down to the temp you plan to use it at, you are ready.

I can't see how chemically it would make any difference beyond that.

 

[mfohl]

When it is first mixed, D-76 is more active than normal. If you use it immediately, your negatives will be developed more than normal.

After 24 hours, the activity will have stabilized, and thereafter will remain quite consistent for some time, until the developer starts to degrade due to age.

I don't have quantitative information about how much over-development will occur because of using freshly mixed developer.

I just mixed a batch a week or so ago. I mixed it in the afternoon, then used it in the evening after it cooled. The negatives seem OK to me; I don't notice anything different from negatives developed after waiting.

-- Mark

 

[markbarendt]

Will it stil mix OK with tap temp water? Or does the water have to be heated?

D-76 requires hot water, forget the exact temp. It will say on the package.

Ilford's ID-11, a D-76 look alike, needs 40C / 104F so hot tap water depending on your set up at home may work.

 

[jensenhallstrom]

Will it stil mix OK with tap temp water? Or does the water have to be heated?

The temp needed to be heated to is 122F to 131F, somewere in that range, also distilled water is a hell lot better than tap water for mixing any chemistry, especially developer. Tap water has many minerals in it, whereas distilled has none.

 

[Hatchetman]

Can you mix a stronger solution and then cool it off quickly with cooler water to reach the proper concentration?

 

[Ian Grant]

Can you mix a stronger solution and then cool it off quickly with cooler water to reach the proper concentration?

You could, however it's not really an advantage.

When I used deep tanks and ID-11/D76 we always noticed the first few films in a new batch lacked the quality of the later films, first fresh D76 hasn't had time to equilibilise which takes a few hours, and second later films benefit from the slight build up in bromide and other pocessing by-products once a few films have been processed. The Highest quality from full strength ID-11/D76 is when used replenished, followed by using at 1+2.

Remember these developers were designed for replenishment from the outset.

Ian

 

[MattKing]

Since you used the word "legitimate", I'd say Kodak and Ilford are probably the most legitimate sources for D-76/ID-11. Follow their mixing/processing directions. I don't think either company indicates any kind of "stabilization" period is needed after mixing.

Michael:

IIRC, the package directions themselves on D-76 recommend waiting 24 hours after mixing.

 

[markbarendt]

You could, however it's not really an advantage.

When I used deep tanks and ID-11/D76 we always noticed the first few films in a new batch lacked the quality of the later films, first fresh D76 hasn't had time to equilibilise which takes a few hours, and second later films benefit from the slight build up in bromide and other pocessing by-products once a few films have been processed. The Highest quality from full strength ID-11/D76 is when used replenished, followed by using at 1+2.

Remember these developers were designed for replenishment from the outset.

Ian

The problem you describe here is typical of replenished systems, but not one shot systems, there is no build up of anything with one shot.

As to equalizing, what reactions are going on?

 

[markbarendt]

Michael:

IIRC, the package directions themselves on D-76 recommend waiting 24 hours after mixing.

Ilford's info does not.

I haven't been able to find a copy of the D76 mixing instructions.

 

[selmslie]

.... Tap water has many minerals in it, whereas distilled has none.

It depends on your water supply, not all dissolved minerals are detrimental. Kodak designed their chemicals and development times for "normal" tap water whatever that is. They do not specifically recommend distilled water because it might actually change the developer's performance slightly. I would be more concerned with the water used with the Photo-Flo, which at least ought to be filtered - distilled might be even better.

 

[markbarendt]

It depends on your water supply, not all dissolved minerals are detrimental. Kodak designed their chemicals and development times for "normal" tap water whatever that is. They do not specifically recommend distilled water because it might actually change the developer's performance slightly. I would be more concerned with the water used with the Photo-Flo, which at least ought to be filtered - distilled might be even better.

selmslie you are right that chemicals designed by the likes of Kodak and Ilford are designed to be used with tap water.

The biggest advantage of me using distilled to mix the chemicals is that eliminates a variable.

 

[Sal Santamaura]

...IIRC, the package directions themselves on D-76 recommend waiting 24 hours after mixing.

I'm looking at a package of D-76. It has no such recommendation. The directions say (using graphics as well as words):

"To Make 800ml (tap) water at 50-55C / 122 - 131F → Stir (contents of packet) Until Dissolved → add (tap) water to make 1 Liter"​

 

[MattKing]

I'm looking at a package of D-76. It has no such recommendation. The directions say (using graphics as well as words):

"To Make 800ml (tap) water at 50-55C / 122 - 131F → Stir (contents of packet) Until Dissolved → add (tap) water to make 1 Liter"​

Thanks Sal - I was hoping someone here would actually have a package to look at.

I've obviously confused my sources.

FWIW, there is no reference to this issue (or mixing in general) in any of the various Darkroom Dataguides I have here. And as Michael noted, there is no reference to mixing in the dataguide for D-76.

EDIT: I'm sure though that somewhere there are or were instructions that specifically referred to allowing the developer to cool to room temperature.

 

[fotch]

Where did you get that info? I never read anything that said that from Kodak, did I miss it?

 

[DLawson]

Since you used the word "legitimate", I'd say Kodak and Ilford are probably the most legitimate sources for D-76/ID-11. Follow their mixing/processing directions. I don't think either company indicates any kind of "stabilization" period is needed after mixing.

This is a frequently repeating question.

As I recall explanations from PE and others with knowledge beyond mine, D-76 mixed from standard formulas is more active for several hours after initially mixing. D-76 from a Kodak package has added buffering agents to compensate for that.

Since I do the perpetual gallon jug with replinishment, waiting 24 hours after the rare new batch is no big deal. I just mix stuff in that before-mode, when I'm clearing clutter and dust so I am ready to deal with film. (Maybe I need to improve my housekeeping in general.)

 

[mfohl]

EDIT: I'm sure though that somewhere there are or were instructions that specifically referred to allowing the developer to cool to room temperature.

That's where the time/temperature thing comes in: x minutes at 68F or whatever. I use D-76 at 1:1; maybe I could mix it with ice water immediately after mixing it, but I never messed with that. I will sometimes put the bottle into a small tub of the coldest water that will come out of the tap. This hastens the cooling a little bit. I usually wait a minimum of four hours.

I have D-76 packets downstairs; tonight I will scour the packet and check for waiting a bit.

-- Mark

 

[cliveh]

When making up D76 you have to wait for it before adding the cold water. It is a bit analogous to waiting for a draught Guinness to settle before drinking it.

 

[Arklatexian]

Hi, ive seen a thread or two on this subject, some people have explained they havent had any trouble with using their freshly mixed stock d-76 as soln as it cools, others say you have to wait 24 hours after mixing to use. Can i get a legitimate explanation why this 24 hour rule would help the developer in whatever aspect rather than using as soon as it cools? Thanks.

I remember some of the old timers around here pouring an ounce or two of old (oxidized) D-76 into a gallon of freshly mixed to "season" the new developer and get away from the 24 hour wait..........Regards!