D-76: full strength or 1:1?

xwhatsit said:

It's not different, it's the same thing. 1 cm on the map to every 10,000 cm on the ground. Likewise, 1 mL of developer to every 3mL of water.

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By that logic that's 1 in 3 or 1+2.

Ian

1:3 in standard layperson's usage, using ratios as ratios, is "one to three." This means that whatever is on the left is one in four (one quarter) of the final volume, and whatever is on the right is three in four (three-quarters) of the final volume.

For scientists in certain areas, who use a colon to indicate dilution factors instead of dilution ratios, 1:3 does mean "one in three," in regards to dilution of a solute into a solvent.

So, Kodak should feel/be at liberty to employ whichever use they would like. 1:3 used as a scientific dilution factor to mean that 1/3 of the final solution is made of developer stock is perfectly acceptable usage. 1:3 used as a dilution ratio to mean that 1/4 of the final solution is made of developer stock is also perfectly acceptable usage. They have decided to go with the more commonly-understood meaning of a colon between two numbers.

Not only this, but they explain this in several of their technical publications. For instance, in the publication entitled "Chemicals for Kodak Professional Black and White Films," a quick reference chart that lists their pre-made developers and many of the specifications relating to them, there is a column entitled "Typical Dilution." In parentheses after this title, they include the information that the colon indicates the ratio of "stock or concentrate:water." This is crystal clear to me. Since "water" is what the number on the right side of the colon represents, then the ratio obviously means "A to B," not "A in B." It could not be "A in B," because B would not be "water" in this case, but would be "working solution," containing developing agents as well as water. If they had meant to explain that the colon is indicative of stock or concentrate in final working solution volume, then they would have made this crystal clear by saying in parentheses, "stock or concentrate:working solution."

So, not only is Kodak's method acceptable for their use, but they explain what they mean to those willing and able to read their publications.

Does anyone here in this thread truly claim that using 1:3 to mean "one to three" as opposed to being used to mean "one in three" is never correct usage? Or are you all just making the argument that Kodak ought to use a more scientific standard (dilution factor as opposed to dilution ratio) in their directions?

If you wish to argue the latter, OK. You have a great argument to make. You are correct by many peoples' ways of working. However, if you are arguing the former, please do not keep making the claim that 1:3 does not ever mean "one to three," or that this is a generally unacceptable way to understand a ratio. This is not the case at all. Both are perfectly acceptable.

Again: I have never been confused by developer instructions from any manufacturer...but then again maybe this is not so surprising, because because I actually do read manufacturer's publications related to what I am doing.

Ian Grant said:

By that logic that's 1 in 3 or 1+2.

Ian

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Hmm. Mebbe I'll just stick to my stock Microphen

xwhatsit said:

Hmm. Mebbe I'll just stick to my stock Microphen

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Just read the instructions and manufacturers' publications that are related to what you are doing, instead of A.P.U.G. arguing threads, and you will be absolutely fine.

RalphLambrecht said:

Very good point!
I wish Kodak would clearly state this somewhere. But again, the 1+x convention is less confusing, because it does not require this distinction.

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As mentioned in my post above, Kodak do state this somewhere, any time in any of their publications when they say "(stock or concentrate:water)." I found it in the first PDF I opened up (this PDF being the logical Kodak publication to consult when trying to find out their explanation of what ":" means in their publications), and I am guessing that the same explanation is in more of them.

Would it be nice if data sheets came with every Kodak product? Absolutely...but they done did away with that years ago.

iandavid said:

Nope. I know that you like to be right, but here you are not.

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Says who?

iandavid said:

The colon works in different ways in different contexts: sometimes it is even just a punctuation mark!
I would say that you are currently speaking out of yours

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It "works in different ways"... How convenient!

iandavid said:

If someone says that substances A, B and C must be mixed 3:4:2, you need to appreciate that this is a ratio but not a fraction.

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Right hand or left hand associative?

Oh right! I forgot you mean an addition, not a ratio.

iandavid said:

On the other hand, the scale on a map is understood as a representational fraction (even outside of the Netherlands), and can properly be treated as such. Mental flexibility is key to survival in the world! And, if in doubt, read the instructions provided with your colon.

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Yes, yes. How convenient to be able to claim that things work the way you say they do, when it suits you!
I'm very flexible. But i wouldn't be that flexible to make such a lousy claim. You can bend too far, you know.

2F/2F said:

My understanding of ratios comes from the subject of raw mathematics, which is why I consider 1:3 to mean 1/4 to 3/4, as opposed to 1/3 to 2/3.

Due to what I learned in my U.S.A. public grade school, I read that 1:3 does not equate to the fraction 1/3. .

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Indeed. If x:y was equivalent to x/y there would only be one notation. Perhaps the Ontario Public school system really is better than I thought, but I remember taking ratios some 40 plus years ago, and remembering them as X to Y, resulting in X+Y units. There is a posibilty when diluting stuff that you end up with slightly less than X+y as one thing may dissolve in the other. If one part was Vodka and the other part was orange juice for example.

NOW The folks who see the ratio as equivalent to the fraction x/y, may indeed be from another part of the world where the conventions may be different. perhaps that is why the folks at Agfa and Ilford use the x+y notation to be sure.

We should be clear that in Kodak speak something like 1:31 results in 32 units of stuff.

I agree with "fschifano" at this point that the side issue has gone on for long enough. Can we now get back to the original question, which was as I recall which are the advantages and disadvantages of using D76 and its friends like ID11 at 'full strength" versus Mixing with equal parts of water. (or 1 part developer to three parts of water as some folks seem to use)

Q.G. said:

How do you interpret scales on maps? If it says 1:10,000, do you take it to mean that 1 inch on the map equals 10,001 inches on the ground? Or 10,000 inches?

So why do you think it would be different here?

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The only difference here is you are putting both in the same container. 1:50 so you have 1 part of the first thing and 50 parts of the other. Then you stick them together and mix. if they are not miscible you then have 51 parts.

I had not bothered checking this thread out -- then saw all the posts and thought it must have a bunch of real good info on using different dilutions of D-76 that I could pass on to our students (we recommend one part D-76 added to one part water, BTW).

Instead I find the typical forum BS -- fine fertilizer for fine minds!

Does D-76 have any silver solvents in it that can be rendered less effective by dilution? I use to use Microdol-X (1 part dev added to 3 parts water) on my Pan-X 120 film for great negs enlarged to 16x16. The 1 part dev added to 3 parts water dilution was suppose to yield sharper looking prints, while more concentrated solutions would dissolve the edges of the silver grains to give fine grained images...but at the cost of less appearent sharpness (less acutance, I believe).

Vaughn

cmacd123 said:

The only difference here is you are putting both in the same container. 1:50 so you have 1 part of the first thing and 50 parts of the other. Then you stick them together and mix. if they are not miscible you then have 51 parts.

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No. no. You take 1 part of one thing in a quantity that is 1:50 part of the total you want to end up with, i.e. you need 49 parts of something else.

Is this really going round in circles?

2F/2F said:

For scientists in certain areas, who use a colon to indicate dilution factors instead of dilution ratios, 1:3 does mean "one in three," in regards to dilution of a solute into a solvent.

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People...

A little research will indicate that the sentence above is the truth of the matter. Research and clinical (medical) chemists use the colon notation to denote dilution factors (x in y). Pharmacists (and many other technical professionals) use it to denote dilution ratio (x to y). The same has traditionally been true in photography. Despite the same notation, the usages are two completely different things and confer advantages depending on field. If you are compounding (as we are doing in the darkroom), the dilution ratio is the most intuitive and useful. If you need to give account for absolute concentration, say for quantitative analysis or for analytical reagents, dilution factor is your best tool.

I have only been working with darkroom chemicals for 40 years, but during that time 1:1 has never meant full strength in materials from any manufacturer or in books from any author. I would suggest that the less the waters are muddied on the matter the happier it would be for everybody. This is particularly true considering the huge volume of legacy formulations and instructions from the masters of the field using the ratio notation. For those that don't like it, the x+y notation is a good compromise. For everybody else, I suggest that you learn to live with it.


Steve

Vaughn said:

Does D-76 have any silver solvents in it that can be rendered less effective by dilution? I use to use Microdol-X (1 part dev added to 3 parts water) on my Pan-X 120 film for great negs enlarged to 16x16. The 1 part dev added to 3 parts water dilution was suppose to yield sharper looking prints, while more concentrated solutions would dissolve the edges of the silver grains to give fine grained images...but at the cost of less appearent sharpness (less acutance, I believe).

Vaughn

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Yes D76 contains the same amount of Sulphite as Microdol-X so dilution past 1+2 has a detrimental effect on grain size, but better edge sharpness (acutance) as the solvency effect is greatly reduced.

Ian

Vaughn said:

I had not bothered checking this thread out -- then saw all the posts and thought it must have a bunch of real good info on using different dilutions of D-76 that I could pass on to our students (we recommend one part D-76 added to one part water, BTW).

Instead I find the typical forum BS -- fine fertilizer for fine minds!

Does D-76 have any silver solvents in it that can be rendered less effective by dilution? I use to use Microdol-X (1 part dev added to 3 parts water) on my Pan-X 120 film for great negs enlarged to 16x16. The 1 part dev added to 3 parts water dilution was suppose to yield sharper looking prints, while more concentrated solutions would dissolve the edges of the silver grains to give fine grained images...but at the cost of less appearent sharpness (less acutance, I believe).

Vaughn

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...back to your regularly scheduled discussion...

D-76 contains sodium sulfite as a silver solvent to reduce grain. Whether dilutions higher than 1:1 (1+1) will increase acuitance is anyone's guess.

There is no right vs wrong here, Kodak has their method, most consumers understand it, therefore, there is no argument that makes sense. Rather, its become "my daddy is smarter than your daddy, so there". Give it up already.

JMHO

Nope,,, it's a lot like the one at my work that just kills me. Engineers arguing over the 24 hour clock. 00:00:00 or 24:00:00 Just depends on which religion,,, no no no,,, not religion,,, SCHOOL,,, i meant school ;-) they're from. (Then it degrades into rounding significant digits, but that's more political than religious).

fschifano said:

Will this bickering never end????

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