D-76: full strength or 1:1?

[Ian David]

If the goal is to allow mathematically ignorant people to properly mix their photo chemistry, they I think both 1:1 and 1+1 are pretty equally undesirable in the grand scheme of things, compared to simply using fractions, e.g. "1/2 stock, 1/2 water."

1+1 is a little more clear to an ignorant person that is 1:1, simply because there are a lot of uneducated people who don't know what a ratio is.

Then again, if they can't figure out such an incredibly simple thing, should they really get to have us help them out?

I'm sticking with the colon as my way of writing it, and fractions as the way of explaining it in words to students.

The great part of this? Everyone is right...er, correct!

Seems the only people having trouble are chemists. I suggest an instructional DVD, with a short demonstration vid, be included with all developer packets to help out the chemists.

 

[RalphLambrecht]

You do realize that only Kodak is using 1:1?

 

[Ian David]

You do realize that only Kodak is using 1:1?

Excellent! Only Kodak needs to include the DVD for the confused chemists

Seriously, no ordinary person is confused by the 1:1 notation until some confused chemistry student says to them, "Gee, 1:1 sure doesn't mean 1+1 in my college chemistry lab. All the conventions from my lab must surely apply in the real world too?! This is all terribly confusing. If you aren't confused, you really should be!"

 

[RalphLambrecht]

Excellent! Only Kodak needs to include the DVD for the confused chemists

Seriously, no ordinary person is confused by the 1:1 notation until some confused chemistry student says to them, "Gee, 1:1 sure doesn't mean 1+1 in my college chemistry lab. All the conventions from my lab must surely apply in the real world too?! This is all terribly confusing. If you aren't confused, you really should be!"

Ian

Seriously, indeed, there is little confusion with 1:1 vs 1+1, but when it comes to 1:3 vs 1+3 it becomes a different matter.

 

[Ian David]

Ian

Seriously, indeed, there is little confusion with 1:1 vs 1+1, but when it comes to 1:3 vs 1+3 it becomes a different matter.

No, there is no confusion with 1:1 and, therefore, there is no confusion with 1:3. If you get one (which everyone does, save the aforesaid confused chemistry students), you surely get the other, no?

Ian

 

[RalphLambrecht]

No, there is no confusion with 1:1 and, therefore, there is no confusion with 1:3. If you get one (which everyone does, save the aforesaid confused chemistry students), you surely get the other, no?

Ian

Ian

It's confusing to some. You need to leave it to the people who are confused to decide if it is confusing or not. You cannot decide that for them!

 

[karthik]

Can we also please include (a) plastic vs. SS tanks, and (b) pre-soak vs. no-presoak in this discussion? I think people are running out of steam on the "1:1 vs. 1+1" question.

 

[Ian David]

Ian

It's confusing to some. You need to leave it to the people who are confused to decide if it is confusing or not. You cannot decide that for them!

OK, OK, Ralph, I'll make some concessions
1. Some people are confused;
2. Although the ordinary man/woman in the street understands that 1:1 = 1+1 (and 1:3 = 1+3), the "+" is probably preferable because it doesn't confuse that handful of people who expect their lab conventions to have universal application outside the lab;
3. Threads like this confuse people who were not confused before, because it gives the confused people in point 2 above an opportunity to air their delusions as though they were perfectly reasonable!

Ian

 

[RalphLambrecht]

...
2. Although the ordinary man/woman in the street understands that 1:1 = 1+1 (and 1:3 = 1+3), the "+" is probably preferable because it doesn't confuse that handful of people who expect their lab conventions to have universal application outside the lab. ...

Fully agree, however, we all to often make the assumption that what we prefer, believe or do is 'normal' and therefore also preferred, believed and done by others. Being involved wit adult education has taught me differently over the last 30 years.

 

[fotch]

Ha, this is funny. Maybe instead of a DVD, it should be a little comic book with pictures of the mixing method.

 

[MattKing]

A somewhat related question:

When you are discussing these numbers, how do you verbally express them?

When I see 1:3, I say "one to three", meaning one part stock to three parts diluting water.

 

[Q.G.]

I do think that there is a huge potential for confusion.

1:3 = 1/3, or "one in three", not 1+3 (=1/4) or "one to three".
1:1 by that same understanding is undiluted.

"+" (addition) and ":" (division) are completely different operations.

 

[Ian Grant]

A somewhat related question:

When you are discussing these numbers, how do you verbally express them?

When I see 1:3, I say "one to three", meaning one part stock to three parts diluting water.

1:3 one to three means 1 part Developer made up to (diluted to) 3 times the volume, same as 1+2. Regardless of what anyone says Kodak have gone against years of convention. It's more common in medicine & science where 1:100 or 1:1000 is I part made up to a total of 100 or 1000.

Other manufacturers are far clearer and some would say 1:10, 1:20. 1:30 adding the 1+9, 1+19 & 1+29 in brackets.

Ian

 

[Ian David]

1:3 one to three means 1 part Developer made up to (diluted to) 3 times the volume, same as 1+2. Regardless of what anyone says Kodak have gone against years of convention.

Kodak may have gone against years of chemlab/medlab/etc convention, but that is because "1:3=1+2" is not how the rest of the world (outside labs) understands ratios. This deviation of the original thread is about what Kodak means by 1:3, not what your average chemist means by 1:3. What Kodak means is perfectly clear from the front of any packet of developer.

Ian

 

[Grif]

Well,,, lets just be happy it's usually volume/volume and not gram/moles weight/volume and all the other iterations that kill chem students. Besides,,, one to three or one in three, you'll likely get by just fine as long as you've done your own ASA/Time/Temp tests and don't change up in the middle of the race.

 

[Q.G.]

[...] "1:3=1+2" is not how the rest of the world (outside labs) understands ratios. [...]

Yes, it is.

 

[Ian David]

Yes, it is.

Sorry QG - you are deluded... Ask some people on the street.

 

[MattKing]

Could part of this potential confusion be geographic? European vs. North American?

 

[Q.G.]

Could be, yes.
If i'd ask people in the street, as Ian David suggested, i'm sure they'll all say that 1:3 means 1/3, i.e. in a mix, one third part of the total is made up of the stuff that should be mixed in "1:3". I.e. one in three, 1+2.
":" is divison, not addition.

 

[2F/2F]

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. Ratios express simply that there are parts of something compared to equally-sized parts of another. One can use a ratio to learn information that one then uses to perform mathematical operations, but the ratio itself does not state that an operation is to be performed, as do 1/3 (divide) or 1+3 (add). It means one part in relation to three parts, parts being amounts that are the same. Knowing this fixed relationship, you can use addition to determine that there are four parts in all, or division (i.e. fractions) to determine what percentage of the total each part is, or multiplication to scale the ratio up to actual working volumes.

However, this is an old debate...and in the debate, it comes down to the fact that scientists in certain fields use 1:3 to mean that there are three total parts, while most of the rest of the population - the non scientists - use ratios in the way they were learned in mathematics class, not science class.

So, Kodak does it because that it what most public-school-educated people in the United States understand. The instructions are written for the average photographer, not for professional scientists.

I must say, that none of the methods of naming dilutions on any manufacturer's instructions cause any confusion for me...so I fail to see where the practical application of this argument will come into play in our photo work.

 

[Ian David]

Could be, yes.
If i'd ask people in the street, as Ian David suggested, i'm sure they'll all say that 1:3 means 1/3, i.e. in a mix, one third part of the total is made up of the stuff that should be mixed in "1:3". I.e. one in three, 1+2.
":" is divison, not addition.

Yes, I just spoke to a Dutch mathematician (seriously!), who said that a Dutchman would understand 1:3 as 1/3. I concede (grudgingly ) that this may well be an even wider European thing...

Ian

 

[fschifano]

Will this bickering never end????

 

[Q.G.]

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. Ratios express simply that there are parts of something compared to equally-sized parts of another.

Yes. The part, compared to the whole.
1:3 is one in three. 1/3.

Yes, I just spoke to a Dutch mathematician (seriously!), who said that a Dutchman would understand 1:3 as 1/3. I concede (grudgingly ) that this may well be an even wider European thing...

Not just European. It's correct, everywhere.

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?

 

[Ian David]

Not just European. It's correct, everywhere.

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

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

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. 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.

Ian

 

[xwhatsit]

Yes. The part, compared to the whole.
1:3 is one in three. 1/3.



Not just European. It's correct, everywhere.

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?

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.