Hi Folks,

I am real new to this and have a real silly question. I am mixing some stop bath for a ratio of 1:19. Actually I am mixing all my chemicals so it applies to all of them - different ratios of course. Any ways, I need a total amount of liquid to be 600cc. How do i figure out how much chemical and how much water? Is it 1 divided by 19 equalling .053 then multiplying this by 600cc and equalling 31.5cc of chemical and 568.5cc of water? I am close or just out to lunch? Any help is greatly appreciated.

Many Thanks, Wayne

-- Wayne Desbarres (nikonuser1968@yahoo.ca), June 06, 2002

Answers

1:19 means that in a solution which has 20 parts total, 1/20th is the 1. So if your goal is 600 cc's total, figure out the volume of each of those 20 parts. (Divide 600 cc's by 20) That's easy -- there are 20 units of 30 cc's each in 600 cc's. So a 1:19 ratio would be taking 30cc's of whatever it is your're diluting (that would be the "1") and adding it to 19X30cc or 570 cc's. (That's the 19) You have a total of 600 cc's, with a ratio of 30 to 570 which is the same as 1:19.

-- Kevin Crisp (KRCrisp@aol.com), June 06, 2002.

You may want to check the instructions that came with the concentrate - it is most likely 1+19, not 1:19. 1+19 means that 1/20 is concentrate and 19/20 (20=19+1) is water, so you would be adding 30 ml(=cc) of concentrate to 570 ml(cc) of water. If it really says 1:19, your calculation is right, but you may as well use 1:20, it shouldn't make any difference (especially for stop bath - it may make a bit of a difference for developer). The difference becomes important with numbers like 1+1, which means one part concentrate plus one part water and is very different from 1:1, which is pure concentrate.

Hope this helps, and good luck.

-- Peter Langfelder (peter.langfelder@sunysb.edu), June 07, 2002.