D76 is one of the most classic developer that is highly reliable and versatile. It is often taken as the industry benchmark against which newer developers are compared.
In this article, we will study various properties of the D76, in relation to its storage, dilution and usage.
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How do you mix Kodak D76?
D76 comes in two sizes, 1 L (0.26 Gallons) and 3.8 L (1 Gallon). It is advised to prepare a stock solution for storage purposes, only further diluting before development if necessary. To begin, pour all the powder into a container. Pour water at 50-55℃ (122-131 ℉) to make up 80% of the solution, 800ml for 1L pack, and 3L for 3.8L pack. Mix until solution becomes transparent. Top up the rest with water at room temperature, 200ml for 1L pack, and 0.8L for 3.8L pack. Mix well, pour into container, let it cool and sit for a day.
Here is what you need to get ready before mixing the D76 powder:
A container that can hold the designated volume of D76 stock. You can split the solution later on for storage but during the mixing, it had better be all in the same container.
Water heated up to 50-55℃ (122-131 ℉). The heating takes time so this happens in advance of mixing.
Filtered water, for those who live in areas with hard water, like the UK.
Containers intended for final storage. Ideally made of glass, which provides better protection against oxidation.
Once you get these ready, here are the steps, which should also be clearly stated on the D76 package:
Empty the powder from the package into the mixing container. Make sure you transfer EVERYTHING not leaving bits behind.
Pour in the hot water, 800ml for 1L pack, and 3L for 3.8L pack.
Stir with a rod and see the solution turn from cloudy to transparent. Minimise air bubbles.
Top up the solution to the total volume with room-temperature water.
Stir some more.
Transfer into storage containers and seal. Ideally, they should be filled to the brim to minimise oxidation.
Let cool down which, to play safe, can take up to a day.
D-76 is pretty resilient - it is hard to go wrong with it. Enjoy!
How long must you wait after mixing D76?
Kodak states that the solution becomes ready in 24 hours. The main reasons for waiting is to let it stabilise, and to cool down to 20℃ or any other temperature you are developing your film at. Many have reportedly obtained decent results developing merely hours after mixing. Depending on how safe you want to play, this process can technically range from a few hours to a day.
D-76 is traditionally known to be a developer that is relatively chemically stable in the scheme of things. Scanning through the threads of forums will tell you that you can technically use it right after mixing it as long as the solution is sufficiently cool.
That said, it can take quite some time for the stock to cool down completely. Depending on where you are and the season you are in, it can take painfully long to get the stock to cool down to 20℃.
In case this is not obvious, do NOT attempt to speed up the cooling process using an ice bath. It is important that it dissipates heat naturally.
There is no reason why I’d rush this process.
For how long does D76 developer last?
D76 is good for 6 months if stored full-bottle at full strength, and 2 months if stored half-full. Diluted solutions are only good for developing once, while stock solutions can be reused. 1 Litre of D76 is capable of developing 4 rolls of film at full strength, 8 rolls at 1:1 dilution, and so on. Where replenished, 1 Litre of D76 can last you 30 rolls of 135-36/120.
Refer to Kodak’s official data sheet here.
How many times can you reuse D76 developer?
At stock concentration, D76 can be reused. If diluted at 1:1, 1:3 or 1:5, it is cannot be reused. The general rule is that you add 10% to the development time per reuse. This can technically go on until the shelf life of 6 months runs out. But the development time can soon become too long to be practical. It is generally understood to be a risk not worth taking as it leads to inconsistent results.
According to Kodak’s published data sheet on D76, if users are to use it at 1:1 dilution (or higher), they are advised to ‘dilute it just before you use it, and discard it after processing one batch of film. Do not reuse or replenish this solution.’.
It is therefore very clear that D76, once diluted, is NOT designed for multiple use.
If you really need to reuse D76, it is either one of the two ways: 1) compensate with longer development times, or 2) add a replenisher.
It is not advisable to use the developer straight without doing any adjustments, although some have reported success in so doing. As explained by Ansel Adams in ‘The Negative’, the developer loses strength after use. Bromides accumulate in the solution as a by-product of the chemical reactions.
More on replenishment
In the data sheet, Kodak provides detailed instructions for mixing the replenished solution using the native replenisher D-76R. There are certainly other replenishers on the market which you can use, subject to the manufacturer’s instructions.
Kodak stipulates that the replenished solution is good for 4 weeks. So you begin by estimating how much development you will be doing in the span of a month. You then mix D76 with D76R at the ratio of 5:1 to make the volume of solution you need.
This replenished solution enables you to develop your rolls at normal development times. 1 Litre of the replenished solution is able to develop 36 rolls of 135-36/ 120/ 8x10 sheets, 48 rolls of 146-24, and 144 4x5 sheets.
The solution needs to be discarded after the above capacity has been exhausted.
The main pros of replenishing D76 is for economical reasons, which is mostly relevant where tank development is concerned in labs.
Another argument, which in my opinion is more remote, is that for long development times, the existence of silver in the solution due to previous use would also adhere to the film. Some may find the increased density favourable for scanning.
Reasons not to use replenishment include a disproportionate increase in complication with economical benefits, and the introduction of greater inconsistency.
More on extended development
Nowhere did Kodak provide official information in relation to directly reusing D76 stock. Many have gone with the rule of thumb of a 10% increment in development time per reuse.
It might work, as a matter of fact, and you might get decent negatives following the rule.
But in my opinion, it doesn’t quite make sense for any photographer looking to make serious work to go with this approach.
You are effectively changing the dilution and development times for every roll. This alters the look of your negatives, which can be detrimental if you do this for a living - you need to keep your work consistent.
Similarly mentioned above, D76 is not that expensive and therefore the cons may well outweigh the pros with this approach.
How do I dilute my D76?
Store it at stock concentration and only dilute it when you are about to develop film. Kodak mostly advises 1:1 dilution, though using D76 at 1:3 and 1:5 dilutions are common. You simply combine 1 part D76 with 3 parts water to get a 1:3 dilution, or 5 parts water to get a 1:5 dilution. The total volume would be 300ml per roll of 135 film, 600ml per roll of 120.
How to know if mixed D-76 has expired?
If your D76 looks yellow, it has most likely gone bad. But it can sometimes expire without turning yellow. Kodak advises that D76 is good for 6 months if stored full-bottle, 2 months if half-bottle. Alternatively, you can use a film control strip, or a cut-out film leader if on budget, to test the effectiveness of the solution in doubt.
D76 is a clear solution that might still remain clear after expiry, so it can be hard to tell simply by observing its colour.
Personally I would not take the risk if the effectiveness of a developer is in question as I live on the work I produce, though this is seldom an issue because at the rate I shoot, I use up the solution before 6 months.
Unless the shots on your roll absolutely does not matter. Or else, it will cost you more to lose these photos than to buy a new pack do D76 or even bring it to a lab.
If for some reason you really want to test the effectiveness of aged D76, purchase a box of film control strips. Kodak produces them, so does Ilford. These are pre-exposed film strips designed for testing developer strengths.
Alternatively, many have suggested that cutting off a film leader as a test strip also works. The leader should turn black in the developer within a the development time you intend to go with.
Is D76 a one shot developer?
D76 is one-shot if used diluted, anything from 1:1 to 1:3 and upwards. As recommended by Kodak, the diluted solution needs to be discarded after one development.
Summary
In this article, we talked about:
How to mix D76;
How long must one wait after mixing D76;
How long D76 lasts;
How many times can D76 be reused;
How to dilute D76;
How to know if D76 has expired; and
If D76 is a one-shot developer.
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