U of S | Mailing List Archive | alt-photo-process-l | RE: Newbie in lith print

RE: Newbie in lith print



I found a page saying "...A 10% formalin solution should be equivalent
to a 4% paraformaldehyde (by weight) solution...". Concentrated /
saturated formalin is 37% AFAIK, not 40%. Anyway, I'll do the math:

Since it says 100g 4% paraformaldehyde (4g paraformaldehyde) solution is
equivalent to 100g 10% formalin (10g formaldehyde) then you have to use
2.5 units of formaldehyde per 1 unit of paraformaldehyde (10 / 4 = 2.5).
Since Christina's formula calls for 37.5g paraformaldehyde, you have to
use 37.5 x 2.5 = 93.75g formaldehyde. In 37% solution terms this should
make 93.75 / 0.37 ~= 253ml 37% formalin, *if my logic is correct*... I
don't know if the information I got from that page is correct and most
importantly I'm not sure if my logic is correct. Therefore don't rely on
this info ;)

Regards,
Loris.

-----Original Message-----
From: Jusdado [mailto:jusdado@teleline.es] 
Sent: 08 Aralık 2006 Cuma 10:10
To: alt-photo-process-l@usask.ca
Subject: Re: Newbie in lith print


Hello to all:   

Chris, as for it formulates it of the ID-85, don't I have
paraformaldehide, if of formaldehyde (formol 40%) liquid, which the 
equivalent quantity that I should use would be?,  
Thank you and pardon for my English, text translated by computer.