PMK-Pyro+massive chart=Confusion.

[PKM-25]

I may very well win the "Daft-Award" for this, but I am kind of confused over the massive chart's formula of PMK-P for Efke IR820.

It says 2+4+100 for 13 minutes at 70 degrees.

I need 500 ML of working solution for my 120 Paterson tank. So is that 6 ML of mixed concentrate per 100 ML for a total of 10 ML of solution A, 20 ML of solution B and 500 ML of water?

Feel free to enlighten me in any verbal style you see fit, I am probably asking for it on this one, LOL!

 

[nworth]

That's right. You get 530ml of solution. The dilutions are great enough so that you can get away with 10ml of A, 20ml of B and diluting to 500ml without changing the times. That may make measuring easier.

 

[John W]

I note that the massive dev chart seems to always write the dilutions in X+Y+Z format, but that at least some of the original dilutions (notably Sandy King's articles on Pyrocat-HD) are stated instead as ratios, e.g. 1:1:100. For the ratio form of 1:1:100, that would mean 1ml plus 1ml, diluted to 100ml total. This can alternately be stated as 1 part plus 1 part plus 98 parts, for 100 parts total. The additive form is different, e.g. "1+4", means 1 part plus 4 parts, for 5 parts total.

 

[George Collier]

Wait a minute - as nworth says, it's not that critical at these dilutions, but I always took the ::'s to be the same as ++'s.
I thought if the last number was to be the total quantity, the formula would say, "to make XXml".
How are the colons to be read?

 

[Thomas Bertilsson]

It's essentially the same. The colon describes a ratio. So if you have a ratio for any chemical mixture of, say 3:2:1 - you mix 3 parts A to 2 parts B to 1 part C, in that order.
3+2+1 is the same thing.
nworth is correct.

So for the formula above 2+4+100 gives a total of 106ml solution per 100ml water. So if you use 500ml, you multiply 106 by 5 and get 530ml total solution.

- Thomas

 

[John W]

I note that [...]

OY! I was clearly delusional when I wrote that. Thomas is correct, the '+' notation and the ':' notation are identical in meaning. I seem to have been confused by postings elsewhere which assumed the logic of fudging the dilutions as nworth describes.