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# Thread: Consensus on the notation of dilutions

1. Oh man... I can't believe I missed this thread. (while I was out making pictures) I love these!
While we're on the subject of cows, I agree that it's a "moo point" . (definition courtesy of Joey Tribbiani)

Don't mind me; I'll just watch from the sidelines. Carry on, boys.

2. Originally Posted by Tony-S
It really comes down to this: When someone says "use it at 1:1", you cannot be sure if they mean 1 part developer and 1 part water, or just straight developer.
It depends how they say the colon. If it's the normal method i.e. one to one then it's obviously one part developer and one part water.

Steve.

3. Do you guys put on a sock and a sock and a shoe and a shoe or a sock and a shoe and a sock and a shoe?

I used to be firmly in the 1+1 camp. But then I learned that this being the same as 1:2 wasn't universal outside photography.

Bottom line is that everyone knows what we mean, so who really cares?

4. 1:10 is a conventional notation and as any conventional thing it has to be agreed among users to be of any meaning. In your instruction booklet there must be a wording somewhere stating "when we indicate a dilution of 1:10 we mean 1 part of undiluted solution and 9 part of water to give a total of 10 parts" or conversely "when we indicate a dilution of 1:10 we mean 1 part of undiluted solution and 10 part of water to give a total of 11 parts". If there is no such wording, call their call centre.

There cannot be a right convention and a wrong convention, because a convention is conventional in nature. If things were so easy we wouldn't be here struggling with theater/theatre, organization/organisation, etc.

There are plenty of those "ambiguities" in the academic world. When you give an exchange ratio between currencies, you always have to specify which is the dividend and which is the divisor (you can avoid it only when it's obvious). So if I say that the Dollar-Euro exchange in a certain year was 1.2, do I mean €1.2 = \$1 or \$1.2 = €1? Believe it or not, there is no uniform convention.

Even saying the €/\$ exchange is 1.2 is ambiguous because, believe it or not, until before the advent of Forex (let's say 20 years ago) you had certain markets where that would mean €1.2 for \$1 and other markets where it meant the opposite (in certain markets the second currency was, by convention, the dividend and not the divider). This might be wrong "mathematically" but it was the convention in that market and everybody understood that.

And by the way, is it 1.2 or 1,2? Isn't it obvious that the comma is the decimal separator? I have always been taught that. My teacher would have flunked me if I had wrote 1.2 instead of 1,2. And by the way, my University teacher of Mathematics lowered the mark if we wrote the infinite symbol without prefacing with "+" because, in his little brain, "infinite" was ambiguous in meaning.

This is like discussing on which side do we have to drive. It's a convention. Europeans drive on the right side, and the British drive on the wrong side. And they build locks so that their are opened by turning the key clockwise!

Fabrizio

5. Originally Posted by Diapositivo
My teacher would have flunked me if I had wrote 1.2 instead of 1,2.
When I was at school the decimal point was half way up the line like this: 1·2
A dot on the bottom line meant multiply.

With the arrival of the computer keyboard, the full stop became the decimal point as well.

Originally Posted by Diapositivo
Europeans drive on the right side, and the British drive on the wrong side.
No. The UK, Australia and Japan are right. The rest of the world is wrong!

Steve.

6. Originally Posted by Steve Smith
When I was at school the decimal point was half way up the line like this: 1·2
A dot on the bottom line meant multiply.

With the arrival of the computer keyboard, the full stop became the decimal point as well.

No. The UK, Australia and Japan are right. The rest of the world is wrong!

Steve.
And in school I learned that a dot half way up meant multiply. We used x until we got to algebra when it started referring to a variable then learned the dot notation.

Obviously our version is right.

7. Originally Posted by Sirius Glass
No, a ratio is the relationship of two or more things to each other. Stock solution only contains one component; hence it cannot be described by a ratio.

Therefore 1:1 can never be used to describe stock solutions.
Sure it can!

And it follows that

is wrong and 100% BS <== again only one component and therefore cannot be described as a ratio.
No, it's not. I do these things every day in my lab. If it were wrong, then I wouldn't have a job.

8. I have to ask, but who is confused? I am serious, is there any manufacturer that says to mix anything in a manner that anyone is confused about?

For eg, I went to Freestyle and opened a few tech pubs (the Kodak one I got from Kodak.com and Liquidol I have in my darkroom as a tech pub), I am not confused, is anyone else, or is this just a debate of what is better to use? I think it is clear when the manufacturer writes a tech manual what to do; I am not confused with any manufacturer's manuals. Kudos to PE for providing a nice example on his and Troop’s Liquidol of how to mix just incase anyone was confused!!

Czech Republic:
Foma, FOMACITRO STOP BATH FOR BLACK-AND-WHITE PHOTOMATERIALS
"For use, the concentrate is diluted with water in the ratio of 1 + 19."

Germany:
"Dilution: 1 + 29"

England:
Ilford- "For all film fixing applications ILFORD RAPID FIXER is diluted 1+4 with water."

US:
Kodak, Dektol: "Dilute 1 part concentrate with 2 parts water"

US: Liquidol, "To make the working solution, mix the stock solution and water in the ratio of 1:9. For example, to make 1000ml of working solution at 1:9 dilution uses 100ml of stock and 900ml of distilled water (temp 20c/68F)....."

9. Andy,

You make, of course, an excellent point. Most commercial products are pretty clear with their instructions. The problem for me and for many APUG memebers is that we write about photography -- either on personal webpages or on forums, or books. I develop recipes and have been writing like this example: "This is the negative for the title print — f/11, ¼ second, in Defender 55Dwr 1:1 with a splash of 2% BZT, for 5 minutes."

Now that I realize it's ambiguous, I'll have to change every notation on my website. It won't be enough to make a disclaimer/explanation in one place. No one reads a website that way. Ah well, it'll be a good excuse to also root out leftover Klingon notation from my move to Expression Web and to update expired hyperlinks. Sheesh! I think I'd rather weed my garden (and since I live in a rainforest, that's saying a lot.)

d

10. Since this is one of many dilution thread on APUG and almost all of them go exactly like this one, at this point, no one should be confused. Besides, as Andy said, most manufacturers use the notation of their choice and explain in English what they meant by it, it's very clear.

The only one that I am confused on is the Ilford Rapid fixer. Their tech pub and the label on the bottle conflicts with each other. (The bottle label says 1+3 with water and tech pub says 1+4 with water) I'm thinking this is a case of misprint.

Before I joined APUG, I always read x:y as ratios. I never knew the proper scientific notation mentioned in these threads. Of course this being the Internet, we have to argue until everyone agrees on one true universal fact.....

Mooooooooooooooooooooooooo....

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