Re: gum arabic
On Thu, 29 Jan 2009, Keith Gerling wrote:
Can anyone explain what a user might notice if she was using a poorer quality gum? In the experience of the users, how does the pedigree pf the gum affect the print or the process of printing?
Keith, I'm probaably in the minority here -- maybe even a minority of one -- but I've never found any connection between the so-called "quality" of the gum and its qualities in gum bichromate printing. One example that leaps to mind is the Daniel Smith gum: I don't know what it's like today, but some years ago I bought a gallon of their ordinary (peasant) gum, and a pint of their "Premium" gum for 2 or 3 times the price. Maybe it was all that purity that spoiled things, or whatever, but the cheap gum was great from the start (so that, as I mentioned, I got a couple more of the same lot number), and the "premium" was dullsville. (Maybe like the difference between a loaf of baker's whole-wheat pugliese and Wonder Bread?)
I've anyway tried maybe 12 or 15 gums over the years... Gum made for commercial printers tends to be excellent, high-class gum (like the itty bitty bottle of Winsor Newton totally clear water-white gum for water color that costs its weight in gold) was blah.
I wouldn't worry about "archival qualities" either... Not that I speak with authority about the chemistry, but I figure that, hardened by dichromate, odds are good the gum will last as long as, maybe longer than, the paper. Not to mention that the "patina of age" is an enhancement for MOST art (tho I realize that's not this discussion).