Re: dichromated colloids

From: MARTINM <martinm@SoftHome.net>
Subject: Re: dichromated colloids
Date: Fri, 21 May 2004 05:34:22 +0200

> I see. I guess purity may always be an issue - even more so where gelatin
> and gum are involved...

Gum and gelatin are more heterogeneous composition compared to PVA, so
I think purity issue is more sensitive with PVA. Gum has more of a
specification issue, like molecular weight range, etc.

> To the best of my knowledge very little attention has been paid to
> dichromated gum.

Of course, synthetic polymer is much preferrable in terms of quality
control!

> I am not aware of any papers specifically dealing with gum.

Gum arabic as well as other gum, pectin, etc. are heavily used in soft
drink industry and cosmetic industry, so most of available knowledge
is in that context.

> Compared to gelatin, gum is said to require extensive
> pre-hardening. It's likely to provide less index modulation than
> gelatin. So far it seems to resemble PVA. I ignore wether gum shows
> equally good real-time efficiency though.

But most people here are not doing holography, but they are making
pigmented colloids that build some optical density on its own.

--
Ryuji Suzuki
"You have to realize that junk is not the problem in and of itself.
Junk is the symptom, not the problem."
(Bob Dylan 1971; source: No Direction Home by Robert Shelton)