Hydroquinone in d-76: an economic compromise?

BradS · Oct 10, 2006

I was reading up on D-76 and its many variants. Somewhere along the way, I read the statement "manufacturers are forced into superaddativity". I kinda dismissed the claim on first reading...

Separately, I did a quicky cost analysis of a couple home made developers. I was somewhat surprised to find that the cost per liter of D-76/Id-11 is actually less than that of D-23.

Why? In a nutshell, D-23 cost more because Metol is expensive. Then I remembered the superaddativity comment. Manufacturers are motivated to reduce cost, maximize profit. That's what engineers do - they make trade offs. Often producing a technically inferior product that is economically superior.

So, I began to wonder about the Hydroquinone in D-76...Hydroquinone is cheap compared to Metol. Addition of hydroquinone makes it possible to use much less Metol but, it also presents some technical difficulty (e.g. activity of the developer changes, blocked highlihts, etc...). Feels like an engineering compromise.

Ultimately, I am left wondering if D-23 really is technically superior D-76. Even if d-23is clearly inferior from a strictly economic point of view.

Nick Zentena · Oct 10, 2006

D-23 came after D-76 IIRC. So when Kodak had a choice they decided they didn't have enough reason to sell both. If D-23 had come first I wonder if the cost to get everybody to switch would have meant keeping D-23 and not D-76?

But I've got a point -) You can easily try both and decide which you like. Nice thing about mixing your own. Nobody else makes choices for you.

Gerald Koch · Oct 10, 2006

If you use D-76 as a one shot than you might be interested in Grant Haist's suggested replacement, often called D-76H. This formula eliminates the hydroquinone completely and increases the Metol to 2.5 g. Everything else remains the same. The cost reduction by eliminating the hydroquinone more than offsets the slight increase in the amount of Metol. The activity is the same as for D-76 and it may be used either FS or diluted. The capacity is less without the hydroquinone but used as a one shot this really doesn't matter.

However, the main cost in D-76, as in other similar high sulfite developers, is the cost of the sodium sulfite and not the developing agents.

BTW, substituting Phenidone for the Metol will also result in less cost.

srs5694 · Oct 10, 2006

FWIW, my own cost comparison shows that D-23 is less expensive than D-76:

D-23:
metol: 7.5g $0.69
sodium sulfite, anhydrous: 20g $0.10
water to make 1l
Total cost: $0.79
Dilution ratio: 1+1
Cost per roll: $0.10

D-76:
metol: 2g $0.18
sodium sulfite (anhydrous): 100g $0.49
hydroquinone: 5g $0.25
borax: 2g $0.00
water to make 1l
Total cost: $0.93
Dilution ratio: 1+1
Cost per roll: $0.12

These figures are from my costs spreadsheet. They'll vary depending on your costs for the constituent ingredients, which will depend on your supplier, the quantities you buy, your shipping costs, etc. As Gerald suggests, the single biggest cost in the D-76 is the sodium sulfite. In my analysis, I used $18.98 plus $10.00 shipping for a 13-pound pail from The Chemistry Store. If you wanted to cut the cost of D-76, finding cheaper sodium sulfite would be the first thing to investigate. TCS usually has pretty good prices, so finding a cheap local source might be the best bet, to eliminate that huge shipping fee. The biggest cost in D-23, by contrast, is the metol, and the D-76 does indeed have a lower cost for developing agents (metol plus hydroquinone) than does D-23.

Since phenidone's been mentioned, I'll add that E-76 (a phenidone/vitamin C variant of D-76) has a total cost that's identical to D-23 ($0.79/liter, $0.10/roll), at least using my cost figures.

As a meta-comment, I'll say that I'm not too concerned over a $0.02/roll price difference in developers. For that difference, I'm more interested in how well the developer works (which is of course at least partly subjective).

BradS · Oct 10, 2006

Every formula I've ever seen for D-23 has 100g of sodium sulfite - same as D-76.

Here are the assumptions I used in my "back of an envelope" analysis:

Borax: $4 per 76 oz at the grocery store - no shipping.
Metol: $30 + $6 per pound with shipping.
Hydroquinone: $15 + $6 per pound with shipping.
Sodium Sulfite: $16.25 + $8 per five pounds with shipping.
Kodak D-76: $5.95 per gallon available locally - no shipping.
Distilled water $1 per gallon from grocery store - no shipping.

I further assumed that the packaged Kodak product could be mixed in tap water (negligible cost) but that home made developers would need to be mixed in distilled water.

Kodak D-76:
------------
$1.57 per liter.

Home made D-76:
------------------
metol 2g $0.16
sodium sulfite 100g $1.07
hydroquinone 5g $0.23
borax 2g $0.04
water 1liter $0.26
total: $1.76 per liter

Home made D-23:
-----------------------
Metol 7.5 g $0.59
Sulfite 100 g $1.07
water 1000ml $0.26
total $1.92 per liter.

I do agree that I don't worry too much about these small differences in cost but, I bet a big corporation like Kodak does.

srs5694 · Oct 11, 2006

BradS said:
Every formula I've ever seen for D-23 has 100g of sodium sulfite - same as D-76.

My spreadsheet lists it as 20g and indicates I got the formula from a Usenet post, but I don't have the exact reference and so can't double-check it. Anchell lists it as having 100g, so I suspect that either I copied it wrong or the Usenet post copied it wrong. By my spreadsheet, the corrected formula comes out to $1.18/liter or $0.15/roll, which is indeed more than D-76 ($0.93/liter or $0.12/roll), attributable to the greater amount of metol in D-23.

Keith Tapscott. · Oct 11, 2006

Another option which is overlooked, is Agfa 14, it`s lack of mention on photographic and darkroom forums is baffling and is hardly more difficult to make than D-23.

Agfa 14: This developer is similar to D-76 and ID-11 except that it uses no hydroquinone, while the low alkalinity is provided by using a small amount of carbonate instead of by using borax.

The formula is:-
Metol = 4.5 grams
Sodium Sulphite (anhydrous) = 85 grams
Sodium Carbonate (anhydrous) = 1 gram
Potassium Bromide = 0.5 gram
Clean, filtered water to make 1 litre.
If using Sodium Carbonate (monohydrate), use 1.2 grams.

Nick Zentena · Oct 11, 2006

Or you could use D-23 1:3. Which makes it very close to one of the Windisch developers. At least I think it's one of his. The differences are small enough to be weighing errors.

BradS · Oct 11, 2006

I guess I'm not so concerned about the cost. I'm going to keep using D-23 and very little else.

I guess my point was just about the compromises involved in using Hydroquinone really. I mean, photographically, it is something of a nuisance but, clearly, it enables the cost of materials to be substantially lower.

nworth · Oct 12, 2006

Both D-76 and D-23 were designed to be used undiluted, in large tanks, with replenishment. That way they would be used to develop hundreds of rolls per gallon before they were replaced. As originally used, D-23 was significantly (but not a lot) more economical than D-76. It was used a lot by photofinishers. Now, we generally use these devlopers one-shots. The economics change. Many people like D-23 diluted 1+3 (despite the long development time), and at that dilution it is about the same price as D-76 1+1.

Jim Noel · Oct 12, 2006

The way I use D-23, it would be all but impossible to formulate a cheaper developer, although that has nothing to do with why I use it.

I use D-23 straight, sometimes as part "A" of a 2 part developer. As long as I am careful not to contaminate the D-23 with part "B", I can use it for months. I don't count the number of sheets of film I run through it, I just use it.

For Instance, I mixed up 2 liters about 3 weeks ago. SInce that time I have developed at least 30 sheets of 8x10, and 40-50 sheets of 5x7. It is still going strong waiting for the next session. No, I don't always expose this much film in this length of time, but it is good tohave a developer which is not eating me up when such volume becomes necessary.

There was a time when the college where I teach used D-23 with replacement as needed to maintain quantity, in a nitrogen burst system. At the end of each semester I would bring the heavily used developer home for use when total development was needed for greatly increasing contrast.

dancqu · Oct 17, 2006

Keith Tapscott. said:
...while the low alkalinity is provided by using a small
amount of carbonate instead of by using borax.

The formula is:-
Metol = 4.5 grams
Sodium Sulphite (anhydrous) = 85 grams
Sodium Carbonate (anhydrous) = 1 gram
Potassium Bromide = 0.5 gram
Clean, filtered water to make 1 litre.

Other than with some divided developer's 2nd bath
I don't recall any film developer formula where in
borax serves as the source for the developer's
alkalinity.

As for Agfa 14, I think Agfa is throwing us a curve
with that 1 gram of carbonate amongst that 85 grams
of sulfite. Sulfite is the source of alkalinity for both
D23 and D76 and Agfa 14. Dan

dancqu · Oct 17, 2006

Nick Zentena said:
Or you could use D-23 1:3.

Makes a good print developer at close to 1:3.
Close because I brew an 8 - 80 formula D-23; 8 grams
metol and 80 grams sodium sulfite. I've tested using
125ml of solution with 5x7 paper. More exposure is
needed. Results are very similar to Ansco 120.

I've used 1:3 on a few rolls of film and intend to see
how it works at 1:7. I know a 1/2 gram of metol is more
than enough to develope a roll of 120 film. I use 1/2
liter of solution. The 5 grams of sulfite should also
more than suffice. I expect times will be in
the teens.

I've doubts 1:7 will work for prints but will likely
check that out as well. As for required chemistry
D-23 should go as far as 1:11, maybe 1:15. Dan

buze · Oct 17, 2006

As a newbie, the way I see it is that to make D76 in an "economical" manner I have to mix 3.8L of it, and keep it around.

Now if I use the DD-23 (more the Barry Thornson derivative of it) from raw chemicals I can not only reuse the 2 solutions, but I can afford to develop /one/ sheet if I feel like it, and use the B bath with my DDX dev too if I feel like it. I put back the solutions in their bottles and they are fine.
So out of my 2L of solution I can really extract every little bit of power they have, in various interesting ways.

I have a bag of 3.8L D76 powder, but I don't think I'll ever use it now that I have discovered the compensating, self-made, reusable 2 baths..

gainer · Oct 17, 2006

buze said:
As a newbie, the way I see it is that to make D76 in an "economical" manner I have to mix 3.8L of it, and keep it around.

Now if I use the DD-23 (more the Barry Thornson derivative of it) from raw chemicals I can not only reuse the 2 solutions, but I can afford to develop /one/ sheet if I feel like it, and use the B bath with my DDX dev too if I feel like it. I put back the solutions in their bottles and they are fine.
So out of my 2L of solution I can really extract every little bit of power they have, in various interesting ways.

I have a bag of 3.8L D76 powder, but I don't think I'll ever use it now that I have discovered the compensating, self-made, reusable 2 baths..

Why do you not believe that you can reuse the D-75? I did so for many years before I found out about ascorbic acid. I had a mixture of phenidone, hydroquinone and sulfite that was reusable up to at least 6 rolls per quart.

I gave up on 2 baths, except for the kind you mix before use, when I found that the results of using the baths in succession and mixing them before use gave exactly the same gradations. But I'm only 79 years old. What do I know?

gainer · Oct 17, 2006

dancqu said:
Makes a good print developer at close to 1:3.
Close because I brew an 8 - 80 formula D-23; 8 grams
metol and 80 grams sodium sulfite. I've tested using
125ml of solution with 5x7 paper. More exposure is
needed. Results are very similar to Ansco 120.

I've used 1:3 on a few rolls of film and intend to see
how it works at 1:7. I know a 1/2 gram of metol is more
than enough to develope a roll of 120 film. I use 1/2
liter of solution. The 5 grams of sulfite should also
more than suffice. I expect times will be in
the teens.

I've doubts 1:7 will work for prints but will likely
check that out as well. As for required chemistry
D-23 should go as far as 1:11, maybe 1:15. Dan

You may run into low pH problems with 5 g sulfite. Metol does have the H2SO4 on its tail. Maybe a little borax will be a good thing.

gainer · Oct 18, 2006

Here's another thought. Substitute ascorbic acid for the sulfite. Now you know you will be in pH trouble, so add some sodium carbonate. I think you might get a pretty good developer.

Gerald Koch · Oct 18, 2006

buze said:
Now if I use the DD-23 (more the Barry Thornson derivative of it) from raw chemicals I can not only reuse the 2 solutions, but I can afford to develop /one/ sheet if I feel like it, and use the B bath with my DDX dev too if I feel like it. I put back the solutions in their bottles and they are fine.

Divided development depends on the film imbibing enough developing agent to provide proper development. These developers were formulated when film emulsions were quite a bit thicker. There have been numerous posts on the net that they do not work well with todays thinner emulsions. Before using any DD I would recommend a comparison test between it and a conventional developer. Chemicals are cheap in comparison to film and trying to save a few cents by using a DD may be a foolish economy.

dancqu · Oct 18, 2006

gainer said:
You may run into low pH problems with 5 g sulfite.
Metol does have the H2SO4 on its tail. Maybe a little
borax will be a good thing.

A 1% sulfite level with a 1/2 liter solution. A 1/2 gram
of Metol. I've processed with as little as 0.3, 0.9, 0.9,
grams Metol, sulfite, carbonate with full development.
Perhaps a little more time with only the 5 grams of
sulfite. That's my 8 - 80 D-23, 1:7. Dan

Tom Hoskinson · Oct 18, 2006

Recall that D-76 was formulated by Kodak (1926-27) as a motion picture film developer. It was mixed in multi-gallon batches and replenished.

Kodak's R&D Lab folks cooked up a lot of variations on D-76, D-23 (circa 1943) was one of them.

One of the interesting D-76 variants was Kodak Developer D96a2 (another motion picture film developer).

Kodak Developer D96a2
Water 52°C------------ 750ml
Metol------------------1.5g
L-Ascorbic Acid------2.0g
sodium sulfite (anhydrous) 75g
borax (decahydrate) 4.5g
potassium bromide 0.4g
calgon 1.0g
water to make 1 liter
pH (at 25°C , ± 0.05) 8.50
specific gravity (at 25°C , ± 0.003) 1.078

Ryuji Suzuki states about D96a2: "This developer works at comparable development times to D-96, but at a lower pH. Granularity and sharpness is somewhat enhanced."

Hydroquinone in d-76: an economic compromise?

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