Wayde Allen (wallen@boulder.nist.gov)
Fri, 04 Jun 1999 08:18:43 -0600 (MDT)
On Thu, 3 Jun 1999 FotoDave@aol.com wrote:
> Some have decided to use hard gelatin and said it worked best for them. I was
> and am interested in knowing if one make, say, a 10% solution of hard
> gelatin, and a compatibly hard solution (more percentage) of gelatin with a
> softer gelatin, will it work more or less the same.
I believe that the answer is yes, but haven't tested that.
> I find it difficult to understand (although I am not saying that it is wrong)
> that sugar is used as plasticizer. Direct feeling would tell me that the
> emulsion would become brittle with sugar, as you also found. Honey is also
> used, which makes more sense to me; but in either case I can't find a good
> explanation. I have my "guess" for the explanation, which I will post in
> reply to your other post.
Sugar is hygroscopic and helps to retain water in the gel. The water is
what actually helps to plasticize the gelatin film. I do think that there
has to be an optimum sugar concentration though. I'd guess that there
must be a point at which adding more sugar doesn't increase the water
retention, and may actually contribute to the film's brittleness.
- Wayde
(wallen@boulder.nist.gov)
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:36