U of S | Mailing List Archive | alt-photo-process-l | Re: gum mixes

Re: gum mixes

hi chris

1. premixed gum: never
2. 300 grams (lumps in cheescloth) plus 1 liter water

Recently I purchased a cheap winemakers hydrometer: http://urltea.com/2f4x It has no baumé scale but degrees baumé can be calculated from the specific gravity scale. Here's a calculator: http://www.ilpi.com/msds/ref/baumescale.html , somewhere I found one the other way round too but I don't have the url at this moment.

Measured my gum and found it was exactly 14 baumé.

Sentisizer: saturated potassium dichromate in a 1:1 mix for all layers


On 23 dec 2007, at 19:18, Christina Z. Anderson wrote:

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!

Christina Z. Anderson
Assistant Professor
Photo Option Coordinator
Montana State University
Box 173350
Bozeman, MT 59717

  • References:
    • gum mixes
      • From: "Christina Z. Anderson" <zphoto@montana.net>