My I should know but do not know question

[one90guy]

I have ordered everything I need to start developing my own film, when mixing chemicals at say 1 to 9, does that mean 1 part chemical to 9 parts water Please do not laugh out loud.
Thanks
David

 

[dehk]

Yes. Usually.
But for Kodak's stuff. They like to use the phrase 1:1, when it's really 1+1.

 

[dehk]

By the way, congrats, and have fun.

 

[MattKing]

I have ordered everything I need to start developing my own film, when mixing chemicals at say 1 to 9, does that mean 1 part chemical to 9 parts water Please do not laugh out loud.
Thanks
David

David:

It is a good question! And you have given the right answer.

The only reason we might laugh is because there are arguments about this issue here.

 

[R gould]

for 1/9 mix 50ml concentrate to 450 ml water to give 500 ml, for 120 and 30ml to 270 for 135mm, and yes, 1/9 means 1 part concentrate to 9 parts water and no, it's not a silly question, Richard

 

[2F/2F]

Kodak uses dilution ratios. This means that 1:9 is one part to nine parts, for a total of ten parts (1+9). This is how most fields and most laypeople understand numbers separated by a colon, and thus is the more correct and sensible usage for the vast bulk of photographic chemical users to understand.

Scientists in some fields use dilution factors, which would mean that 1:9 is one part in nine parts, for a total of nine parts (1/9). This is acceptable use in their specialized fields, but is not common use. However, many of the European contributors to this board seem to use this method, so it may be common use in Europe. I am not sure.

If people are going to make an argument about what Kodak ought to do (i.e. that they ought to use dilution factors in stead of dilution ratios), then they have a valid argument, and ought to make the argument. However, if people are going to state that Kodak is absolutely incorrect in their use of dilution ratios, then they ought to reconsider and re-research their absolutely incorrect statements.

Not only will common sense eventually lead you to conclude that Kodak are not instructing you to split a volume into nine parts, but into ten, but Kodak clearly state in at least one of their general processing data sheets that they are using the colon to mean the amount of stock or concentrate to water to make working solution, not the amount of stock or concentrate in working solution.

It is not a dumb question. If you have any doubts, you should always find out before barreling ahead with your precious film at risk. Most importantly, the question and the answers to it can teach you something very important. It ought to make you realize that consulting manufacturer's data sheets is a prudent step prior to working with unfamiliar materials and procedures. Unfortunately, you have to go "rifling" through manufacturers' Websites to get data sheets nowadays, but they are there, and they are worth tracking down.

 

[Ian Grant]

The way 1+9 is written sounds more complex than the 1:10 or 10x dilution it actually is. 100 ml made up to a litre is very much easier than adding 100ml to 900ml

One Manufacturer used to put both the 1:10 and in brackets underneath(1+9) because of Kodak's misuse of the x:y ratio, which caused confusion.

Ian

 

[Steve Smith]

Most chemistry instructions and labels will say e.g. 1+9 rather than 1:9.

Having said that, most normal people will read 1:9 as 1 plus 9 or 1 part chemistry to 9 parts water. Strange people like chemists will read 1:9 as 1 in 9 and will mix it with 8 parts of water to make a total of 9.

In my opinion the colon is used to represent a ratio so a ratio of 1 to 9 will give a total of 10.


Steve.

 

[fschifano]

Here we go again. Read 2F/2F's post #6 above. That's the deal. There's no need to get nuts over this.

 

[Kevin Caulfield]

Here we go again. Read 2F/2F's post #6 above. That's the deal. There's no need to get nuts over this.

So, we are not allowed to say that Kodak are wrong?

 

[Steve Smith]

I wouldn't say that Kodak are wrong but their method may cause some confusion whereas using a + sign makes it more obvious what is required.


Steve.

 

[Steve Smith]

But for Kodak's stuff. They like to use the phrase 1:1, when it's really 1+1.

That's the one which makes a nonesense of it because if you use the chemist's method, this would be a mixture of one part of concentrate in a total volume of one - so no water added.

In reality it is one part of concentrate to one part of water. Normally referred to as 1+1.


Steve.

 

[jerry lebens]

Absolutely not a silly question.

I studied chemistry before I took up photography and it never occurred to me that the scientific method of dilution was different to the photographic method. It was only by accident that I learned the truth, when I started diluting chemistry with another student who couldn't understand what I was doing - why I was making something, that appeared simple to him, so complicated.
It was very annoying and kind of embarrassing, too : When I tried to explain what I was doing it sounded like I was trying to show off how clever I was but, at the same time, appearing really stupid.

Honestly, I could have done without it.

Regards
Jerry

 

[2F/2F]

So, we are not allowed to say that Kodak are wrong?

What I said, in a nutshell, was that there are at least two acceptable methods for expressing dilutions, and Kodak uses one of these two. Therefore, stating that Kodak's use is flat-out wrong is incorrect. Both are correct, and Kodak could not use both, so they picked one. There are plenty of good arguments as to why Kodak might-should use the other method, and it is great to hear these arguments on A.P.U.G., as long as they are informative. However, those who say that Kodak is flat-out wrong are flat-out wrong. In any case, if anyone thinks that Kodak should change methods, they would be more effective making their case to Kodak proper, not the Internet.

 

[removed account4]

sprint chemistry is easy to use ...
the stop bath for your print-chemistry will indicate when your working solutions are all expired ...
film developer can be replenished or single shot and works great with all films
( doesn't block highlights if over developed ).

( as indicated on the label or on the sprint website )
all their chemistry is stock/liquid and it is mixed 1 part stock solution : 9 parts water
( except for the film dilution of the fixer, it is 2:8 )

they sell it right off their website, if you can't find it locally ...

i have used sprint chemistry on and off since 1981, they are nice folks ...

good luck!
john

 

[hrst]

AFAIK, 1:9 and 1+9 are identical in meaning in any field, also in mathematics and chemistry. : indicates the ratio, the latter part is added at 9 times higher volume than the first one, be it 1 liter and 9 liter making up 10 liters or 0.9 liter and 8.1 liter making up 9 liters. The final volume is irrelevant, the ratio is still ratio. This is what I've been taught at school, and exactly so that : is the sign for this meaning.

I have a feeling that the possible misconception is only born from a concern that someone could misunderstand that, but in reality, the meaning is unambiguous - it's same for + and :. Just like the legendary "two times longer", which cannot be misunderstood in any way in reality and has a long history of completely unambiguous meaning, but there is constant discussion going on the Internet where people are arguing whether it's wrong to say so and what it exactly means.

But I may be wrong! And this may vary greatly from continent to continent. And of course I agree that when using + instead of :, the risk of misconception is lower.

Percentages are surprisingly one of the most difficult areas in mathematics, we just take it for granted and then make mistakes. This is the same kind of problem.

 

[Ian Grant]

In medicine (and similar professions), pharmacy, science, food technology etc etc 1:10 means dilute to a 10% solution, or 1+9, it's not ambiguous at all.

However because Kodak strayed from the accepted convention it is now ambiguous in photographic circles. It isn't outside Photography.

Ian

 

[hrst]

OK, I stand corrected as for the meaning, but after all it seems ambiguous outside photography too, as it is taught at least in two different ways in scientific circles. Too bad but no can do.

See also; http://www.mathleague.com/help/ratio/ratio.htm . The definition of "ratio" itself as a term does not solve this problem, however. "1:9 concentrate to water" means the same as "1:10 concentrate to whole volume". Compare the examples 1 and 2 from the url above. But, single "x:y" won't make clear if it talks about the ratio of two ingredients, or a ratio of ingredient A to the total volume. Both are possible, and from what I read now, both are used. I was under the completely opposite impression than you.

 

[hrst]

As for chemistry;

http://www.shodor.org/unchem/math/r_p/index.html
http://www.chemistrydaily.com/chemistry/Ratio

"Ammonia is a compound consisting of a 1 : 3 ratio of nitrogen and hydrogen atoms."

So, there is one N and three H, total 4 atoms. How does this differ from developer being diluted by taking 1 part of developer and 3 parts of water, making a 25% solution. I can find lots of : notations! This notation seems to be in the basic teaching material everywhere around the world; I've been taught the same way! And you say that it's the opposite, and not even unambiguous?

 

[cmacd123]

Boys Boys, we did this one over a month ago. A:B is a parts of a and B parts of B when in Kodak's Documents. (and By extension any other North American Maker) To avoid confusing old chem majors you may find it easier to Speak of A+B. Good to ask the question, it has been answered, the old thread on this subject is where to continue the argumant if you can add anything new to that

 

[Kevin Caulfield]

What I said, in a nutshell, was that there are at least two acceptable methods for expressing dilutions, and Kodak uses one of these two. Therefore, stating that Kodak's use is flat-out wrong is incorrect. Both are correct, and Kodak could not use both, so they picked one. There are plenty of good arguments as to why Kodak might-should use the other method, and it is great to hear these arguments on A.P.U.G., as long as they are informative. However, those who say that Kodak is flat-out wrong are flat-out wrong. In any case, if anyone thinks that Kodak should change methods, they would be more effective making their case to Kodak proper, not the Internet.

Okay, that's fair enough. Point taken.

 

[one90guy]

Pitching my hat in the door first

Hello
Sorry if I brought up a tense issue But on the good side is my mixing skills should be ok.Most of my stuff will be here Thursday the 4th I feel like the kid on Christmas morning. Also just bought a bulk loader off the ebay, but I can stop buying camera gear anytimmme I want to. I have had to let 3 of my Yashica rangefinders go and just listed a nother one last night to offset the new purchases.
I want to say thanks to each and everyone who posted help for me. I have never found a photo forum with so many folks willing to take the time to help the new guy
David.

 

[clayne]

Here we go again, another x:y vs x+y axe-grinder. Search the archives guys, cmon.

To the OP: yep, you're fine on what you thought. Even if you were off and did 1+10 or 1+8, it wouldn't be the end of the world - although I do recommend trying to be accurate.

 

[Steve Smith]

although I do recommend trying to be accurate.

Accuracy is good, consistancy is even better.


Steve.

 

[Kevin Caulfield]

Accuracy is good, consistancy is even better.


Steve.

Consistency is even better. I'm sorry Steve. I couldn't resist. You did say accuracy is good.