Classic D-76 vs D-76d - results closest to packaged D-76?

[John Gnagy]

Hi all,

I'm new here but have been spending a lot of time reading the old threads. I haven't found a clear answer to this question though so I thought I'd throw it out there. I use D-76 1+1 as a one shot for most of my developing, and I do it at a small scale (usually 2 rolls of 135 at a time in a 4 roll Nikor tank). I buy 1gal packs of D-76, mix it, and store it in 250ml glass reagent bottles filled to the top (minimal air). I dilute it 1+1 right before I develop my film.

I want to start mixing my own D-76, mostly for fun, but also so that I'm in control of the formula and batch size. As a starting point, I would like to use a formula which will get me as close as possible to Kodak's D-76 in results and, ideally, shelf life. There's conflicting information out there on this forum and elsewhere - some say D-76d is close to the packaged D-76 and others say it's not and that it requires longer processing times. Some say D-76d stores better due to the buffering, others say the classic D-76 formula stores just fine in sealed glass bottles. I found this paper indicates that the packaged D-76 stores better than the home mixed formulas it compared to (though D-76d wasn't among them):

http://healthprofessions.udmercy.edu/programs/crna/agm/phenvitc.htm

I want consistent results, but since I'll be in control of the batch size, I don't need it to keep for 6 months. Would the classic unbuffered formula get me processing times and results closer to what I'm used to from the packaged D-76? Or would D-76d get me the same results with better consistency when stored for a while? I'm sure someone here has gone down this path before and can offer some advice. Thank you so much in advance!

John

 

[Gerald C Koch]

The formulas for D-76 and D-76d vary slightly in the choice of buffer composition. Only Kodak knows that exact composition of their packaged D-76. Some have speculated that it is somewhere between D-76 and D-76d. However since the same pH is maintained by either developer there is no difference in use. In other words all other things being equal the nature of the buffer is immaterial as long as the pH is the same. A similar worry has been expressed for Ilford ID-11 vs D-76. BTW the "classic" formula IS buffered just not well.

But since you are using D-76 as a one-shot and not in a replenished system the buffering is really not an issue. So don't worry and mix up your developer from the D-76 formula.

 

[PinkPony]

others say the classic D-76 formula stores just fine in sealed glass bottles

I recently scratch mixed the original D76 for fun, no economical reason. I'm happy with the results. What I know for a fact so far is that it keeps in fully stopped bottles without noticably increased activity for 1 month (when mixed with deionized water). Since I have heard of the buffering problem I have also acquired small glass bottles to keep it topped up all the time. I will keep developing with it to see how long it lasts.

What I think I see:

• Slightly less active than package Kodak D76, at least with TMY2 and HP5+. This may be film dependent... Acros gave normal density negatives for me at 10:00 with D76 1+1 20C.
• Slightly less acutance than packaged Kodak D76. More like D23 which I have also scratch mixed before.

Some samples:
https://www.dropbox.com/sh/0yngi8hi5pmax3g/AACCzvNlA4XrLJePLrlywFd3a?dl=0

 

[John Gnagy]

Thanks for the replies - this is helpful. I wonder why the scratch mixed formula would have lower acutance (I realize it wasn't a scientific comparison, but an interesting observation).

But since you are using D-76 as a one-shot and not in a replenished system the buffering is really not an issue.

So the buffering differences have minimal impact on storage stability (in full, sealed glass bottles)?

 

[Gerald C Koch]

Thanks for the replies - this is helpful. I wonder why the scratch mixed formula would have lower acutance (I realize it wasn't a scientific comparison, but an interesting observation).


So the buffering differences have minimal impact on storage stability (in full, sealed glass bottles)?

Yes, the buffering does however effect replenished systems.

 

[Chris Douglas]

John,
I started mixing my own D-76 about 8 years ago, and quickly experienced the variable activity problem while using the original formula. I went to D-76d and have never had a problem since. I also use 250 ml one shot bottles, diluted 1:1 just before use. I have not noticed any variation in activity after storage up to one year. The only problem I have noticed is that it takes a long time for the boric acid to dissolve. I get my chemicals from the Formulary.

Best regards,
Chris

 

[John Gnagy]

Thanks Chris - sounds like you're doing things the same way I am so this is really helpful.

 

[Gerald C Koch]

I would like to elaborate a bit on the buffering difference between D-76 and D-76d. Both are buffered but the difference is in the buffer capacity. D-76d is better able to withstand the addition of OH- ions caused by the formation of the hydroquinone monosulfonate ion as the developer is used. The reason is that there is just more buffer present in the d version. However as I said before this is only important for replenished systems. Used as one-shots both versions would work equally well.

In fact you can save a bit of money by eliminating the hydroquinone entirely as is done with D-76H. D-76H was designed for use as a one-shot by Grant Haist. Same development times as for regular D-76.

 

[Ronald Moravec]

I compared my compounded with Kodak packaged and results and shelf life are the same.

750 ml water at 125 deg
2 grams metol
100 grams sodium sulfite
5 grams hydroquinone
2 grams Borax

water to 1000 ml
cool to room temp protecting with quality food wrap

decant to one time use size bottles that seal WELL.

Do not use for 24 hours after mixing.

NEVER to a partial stored bottle even if Kodak claims 6 weeks

Lasts 6 months after which activity drops slowly

 

[John Gnagy]

In fact you can save a bit of money by eliminating the hydroquinone entirely as is done with D-76H. D-76H was designed for use as a one-shot by Grant Haist. Same development times as for regular D-76.

I might try this to see how it works for me, but wouldn't the omission of hydroquinone alter the character of the developer? I thought the metol/hydroquinone combination was what made D-76 D-76.

 

[John Gnagy]

I compared my compounded with Kodak packaged and results and shelf life are the same.

Thanks - that's what I was hoping would be the case.

 

[Gerald C Koch]

I might try this to see how it works for me, but wouldn't the omission of hydroquinone alter the character of the developer? I thought the metol/hydroquinone combination was what made D-76 D-76.

D-76 is a typical low pH high sulfite developer of which there are many formulas. So D-76 is really nothing special. Kodak originally developed D-76 as a low contrast developer for motion picture film and not as a general purpose developer.

Haist said that D-76H produced results identical to D-76.

 

[flavio81]

Hi all,

I'm new here but have been spending a lot of time reading the old threads. I haven't found a clear answer to this question though so I thought I'd throw it out there. I use D-76 1+1 as a one shot for most of my developing, and I do it at a small scale (usually 2 rolls of 135 at a time in a 4 roll Nikor tank). I buy 1gal packs of D-76,

If you are using it one-shot, a suggestion is to weight the powder and split it into little plastic bags for making 500ml of straight D76. In that way you don't run into shelf life problems.