Re: gum mixes

[john@johnbrewerphotography.com]

Hi Chris

I mix my own. 300g PLUS I litre of water. I use 13g of K2Cr2O7 with 
distilled water to make a total volume of 100ml. When I use this I always 
make sure there are no crystals before use which is only really the winter 
months when the heating isn't on.

I use 1:1 gum/K2Cr2O7 for my base exposure then change the ratios for 
highlights and shadows. I can normally get a print from 3 layers of gum.

Best wishes

John.

www.johnbrewerphotography.com
----- Original Message ----- 
From: "Christina Z. Anderson" <zphoto@montana.net>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, December 23, 2007 6:18 PM
Subject: gum mixes


> Dear all,
>
> I'm finishing my section on gum thicknesses, and was wondering a question 
> or two of all one-time to inveterate gum printers:
>
> 1.  How many of you are using premixed gum?
> 2.  If  not and you are mixing your own, what dilution are you mixing it 
> at exactly--weight of gum into what volume of water, for instance? If it 
> is 300g in a TOTAL volume of 1 liter, or 300g PLUS one liter please 
> differentiate clearly. If, mixing more than one solution, also state.  If 
> not using gum/pigment 1:1 sensitizer at time of use please note.
>
> Any other practices, I'd love to hear--e.g. using a hydrometer or some 
> such thing. Or if you use dry gum at time of use in your sensitized mix 
> and do not premix a gum solution.  Stuff like that.  I've got the timeline 
> almost finished on gum dilutions from beginning til now and I want the 
> "now" as in 2007.  Hopefully this isn't too pointless, misleading, and 
> confusing!
> Chris
>
> __________________
> 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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