1:1 means 1 part of A and 1 part of B.
1 in 1 means the liquid is neat.
My explanation in the other post was a brain explosion on my part. The ':' and the '+' mean the same thing. The other termonology that can be used is 'in'. They're relationships:
- A:B and A+B equals A in (A+B)
- 1:0 and 1+0 equals neat liquid
- 1:1 and 1+1 equal 1 in 2
- 1:2 and 1+2 equals 1 in 3
- 1:5 and 1+5 equals 1 in 6
- 1:10 and 1+10 equals 1 in 11
- 1:20 and 1+20 equals 1 in 21
- 1:50 and 1+50 equals 1 in 51
- 1:100 and 1+100 equals 1 in 101
Therein lies the problem. 1:10 and 1:100 are log10 dilutions (10^-1, 10^-2) and mathematically you are introducing a very difficult way of calculating dilutions. Nobody I know teaches it your way in biology or chemistry labs because the colon is a ratio. Mathematically, a 1:10 is:
10/1 = 10 dilution factor
If you need 500ml of developer, then
500/10 = 50ml of developer stock.
To determine the volume of water
500ml - 50ml = 450ml of water
450ml of water plus 50ml of developer = 500ml of working developer at 1:10 (10^-1) dilution.
While ratios of 1:10 or 1:11 may be irrelevant for development, 1:2 vs. 1+2 is dramatically different. This is the dilution I use with Pan F+ or Acros with Perceptol. If we use the 1+2 then it's pretty clear that to make 600 ml would require 200ml of Perceptol and 400ml of water.
Your system is inherently confusing, particularly to the uninitiated. I think the fact that your previous post and this post are different attests to that.
The plus nomenclature is unequivocal. The colon nomenclature is, too, to chemists and biologists, but not to a large number of photographers or Kodak. That's why it's problematic.
