Re: gum mixes
Dear all, So this is what I have so far--only 10 gum printers on the list apparently :) The range of practice of gum never ceases to amaze me. In historical times it was 10% gum to 100% gum (the latter was mixed 1 gum powder to 1 water--I know, it is not technically a 100% solution but that was what they termed it in those days--in other words, a 40% solution was 40g gum PLUS 100ml water, not in a total combined volume of 100ml. Some questions: Marek, do you use dry am di at time of use? Henry and David, at time of use you mix essentially a half strength potassium dichromate and am I correct with your 1 di: 1 water: 10 (!) gum? How long are your exposures and are they in the sun? Guido, same thing--do you use that little potassium dichromate in your mix--essentially 1-5 parts gum to only 1/2 part pot di? If I have anyone's info wrong, let me know. Chris 1.. Sam Wang 1+2 powdered and at time of use 1:1 with dry am di 2.. John Brewer 3+10 powdered, preserved with 15ml formalin per liter, at time of use 1:1 mix, changing this ratio for highlights and shadows 3.. Kees Brandenburg 3+10 LUMP which he says is 14 baume and at time of use 1:1 4.. Marek Matusz premixed gum, stock pigment mixes of 1 tube pigment in 120ml gum and at time of use 3pt gum/pigment to 3 pt water to 1 part AMT 5.. Joe Smigiel is premixed 14 baume and at time of use 1:1 pot di, tube pigments, sometimes powder pigments, sometimes mica or interference pigments 6.. Bill Mull is premixed gum and stock pigment made with gouache at 6 gum: 1 gouache and at time of use 1:1 pot di and one coat gums made with paper negs 7.. Hamish premixed gum and stock pigment solutions and at time of use 1:1, but sometimes 1:2 8.. Henry Rattle 70 to 200 Kordofan No. 1 LUMPS with few drops formalin and at time of use 1 di: 1 water: 10 gum 9.. Guido Ceuppens 200g to 850 water with 5gr sodium benzoate with stock pigments of 1 g watercolor tube: 6ml gum and at time of use 1 part stock:0-4 parts gum:0.5 pot di 10.. David Hatton 500g + 1 liter with 10 drops 100% thymol and at time of use 1 pot di:1 water:10ml gum with varying amounts of pigment depending on layer, color ________________ Christina Z. Anderson Assistant Professor Photo Option Coordinator Montana State University Box 173350 Bozeman, MT 59717 406.994.6219 CZAphotography.com
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