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1. ## Chemistry: Ratios

Is a ratio of 1:2, 1 part X plus 1 part Y to make 2 parts or is it 1 part X plus 2 parts Y to make a combined 3 parts?

Would a PMK developer that calls for combing parts of 1:2:100 yield 100 ml or 103?

2. No, Bruce, your second answer is the correct. To reiterate, it is one part of Y and two parts of x

103 is the correct answer. I use 100 ml with 200 ml with 1000 ml for PMK. Sometimes with 4x5 I use 50 ml +100 ml + 500 ml because the tray I use for the developer is smaller.

Just maintain the 1+2+100 and you will be ok.

lee\c

3. I see that more folks are going to the the "+" sign when talking about mixing chemicals. It leaves no doubt that way.

4. Originally Posted by jim appleyard
I see that more folks are going to the the "+" sign when talking about mixing chemicals. It leaves no doubt that way.
That's always been the way here in the UK

1+9 = 1:10
1+1 = 1:2

It's far less ambivalent

Ian

5. Ian, we're a little slow here in the US; look who got re-elected!

6. Originally Posted by Ian Grant
That's always been the way here in the UK
1+9 = 1:10
1+1 = 1:2
It's far less ambivalent Ian
So, 1:1 = 1+0 ?

I don't read it that way. I read 2:5, two parts to five parts,
two ml to five ml, etc. That's a ratio : . Dan

7. I agree with Dan (dancqu) 1:2:100 = 1+2+100

lee\c

8. Originally Posted by dancqu
So, 1:1 = 1+0 ?

I don't read it that way. I read 2:5, two parts to five parts,
two ml to five ml, etc. That's a ratio : . Dan
Then, if you are saying "to", you mean 2 parts diluted "to" five parts, this will yield five parts total. In this case 1:1 would equal 1+0, or 'full strength'.

But if you mean "to" to mean + (why not say +) you would have 7 parts in total.

This is my question. Resolved: In photographic chemistry : seens to mean +. In the future I will use the plus sign and hope Anchell etal do the same.

thanks to all

9. Originally Posted by Ian Grant
That's always been the way here in the UK

1+9 = 1:10
1+1 = 1:2

It's far less ambivalent

Ian
Sorry, but 1+9 is not equal to 1:10.
1+9 is 1 part of liquid added to 9 parts of other liquid. 1:10 is one part of liquid added to 10 parts of another liquid. In reality, photographic solutions should be expressed in percentages. IOW, a 10% solution by volume would be 1+9, but not 1:10.

So for example mixing Xtol at 1:2 is adding 1 part of Xtol concetrate to 2 parts of water and this in effect is a 33.33% solution.

10. In this case 1:1 would equal 1+0, or 'full strength'.

Bruce, I don't see it that way. I see it as one part x and one part y. Would that not yeild 50%?

the symbol : and the symbol + mean the same thing to me.

lee\c

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