Re: Stock Paint:Gum Solutions?
And this is why I would like that -at least in these cases- the percentage were not used but a different, universally understandable and less confusing notation like for example the ratio (e.g. 1:2, 1+3, "2 in 5", etc.).DJ et al, This whole thing used to confuse me so much until one book from early 1900s addressed the fact that a "30%" gum solution (meaning 300g gum + 1000 ml water but sometimes some authors meant 300g in a total volume of 1000ml) wasn't truly 30%. Then I went to just the "practical" or "cooking" method of worrying about gum printing--e.g. "2 in 5" and whatnot.
And this is why the term "part", if not followed by the measure unit (weight, volume, etc.) may be confusing.But DJ brings up a great point--the people who measured pigment by weight. Pigments vary so much by weight, and a lot of time the weaker pigments (e.g cerulean blue) weigh a ton and the stronger pigments (e.g. thalo) weigh very little. Like comparing the weight of ground up rock to the weight of a vat dye. I found that a light pigment weighed 5g and a heavy 9 g. given the same volume, and weight did NOT correspond to covering power or saturation. So I quit using weight as a form of measurement as well.
About the use of "tube" as a measure unit... Who knows what is -and in what proportion- in a tube other than pigment, water and (if possible) gum arabic? This means that comparing tubes to tubes is almost insignificant unless for the same pigment and the same brand.