stwang1@bellsouth.net
Date: 07/27/03-07:08:41 PM Z
Hi Stuart,
Very strange - I replied to this message this morning but it never showed up on the list
discussions. Did you receive it Stuart?
I'll try to recap. No, I have not measured the gum I use, but my guess is that it's not too
different from everyone else's, that is, Gum 14 plus equal amount of water. However, I
have not used Gum 14 for years - the ones I tried all had too much preservative and were
not very soluble after drying. I mix gum granules (tears?) 1 part with 2 parts water, plus
very little preservative. In use, I add 1 part water to 1 part gum, add pigment to the right
color, and then add dry dichromate. My gum "develops" in very short time, usually in 10
minutes or less.
I like to compare making gum prints to riding the bicycle: there are no secret ingredients.
It's working out variables one at a time. When one hasn't lerned to balance on the bike, it
looks so hard. Once he/she learned to ride, it's easy as pie. Talking about it doesn't get
you very far. No doubt you would agree, Stuart - I saw a lot of elbow grease on your
prints. ;-)
Sam
>
> From: Stuart W Melvin <swmelvin@earthlink.net>
> Date: 2003/07/27 Sun AM 10:58:17 EDT
> To: alt-photo-process-l@sask.usask.ca
> Subject: Sam...jump in here
>
> oooops......thanks for the info.
>
> To be more scientific.....we all get the gist......How thick is the stuff
> Sam?
>
> corrections applied:
> I'm wondering if you might be able to elaborate on the viscosity of the gum
> solution you use. Have you ever measured it with a baume meter? <disregard
> baume meter question. What
> ratios of water to gum (solution or powder) do you prefer?. Is your
> viscosity preference consistent or do you find you vary it for any reason?
> How does your viscosity preference relate to your application technique? So
> many question marks........I must admire your technique hey.
>
> Thanks,
> Stuart
>
> -----Original Message-----
> From: Clay [mailto:wcharmon@wt.net]
>
>
> Sent: Sunday, July 27, 2003 8:18 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Dry Dichromate and Gum, was Re: News from APIS
>
>
> Industrial viscometers are pretty pricey. But googling "viscosity
> measurement" gives you a nifty science project link:
>
> http://www.science-projects.com/Viscosity.htm
>
> that makes me think that measuring relative viscosity would be pretty
> simple. If one uses the same size tube and bead, then the time it takes
> to sink would give an idea of relative viscosity between two fluids,
> since gravity is (at least for the precision involved here) the same
> everywhere. Maybe at the next gum printers summit, everyone can
> standardize on a 1/2 inch diameter 20cm tube and Daisy BB pellet or
> whatever. Then when someone asks about your coating viscosity, you can
> just say "4 seconds". Nice and low tech.
>
> Clay
> On Sunday, July 27, 2003, at 01:57 AM, Katharine Thayer wrote:
>
> > Stuart W Melvin wrote:
> >>
> >> Hey Sam,
> >>
> >> I'm wondering if you might be able to elaborate on the viscosity of
> >> the gum
> >> solution you use. Have you ever measured it with a baume meter?
> >
> > Sorry to jump in here, but just thought I'd interject the comment that
> > you're making the same mistake I'd been making all my life until a
> > couple of weeks ago, when Gordon enlightened me. A baume meter
> > (hydrometer) measures specific gravity, not viscosity, and what's more,
> > the two are not related to each other. This information came to me like
> > the apple falling on Newton's head, and this is why I asked the other
> > day the speculative question about differences in viscosities between
> > gums. I don't know if any of us has the equipment to answer this
> > question; if someone does I'd sure like to know about it.
> > Katharine
> >
>
>
>
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