Re: Chrome Alum Gelatin hardener

> > Perhaps I skipped a line, a page or two?

> I think you are skipping a lot.
(Is this a "Good try for a provocative response"?)!!

Dear RYUJI (though Ryuki sounds OK too),
Are you being rude AND sarcastic or just plain rude?

Again you avoided answering my question and choose instead
to flood the list with more superflous, very often useless
(as in ilrevelant), occassionialy misleading and sometimes
plain wrong "facts" while trying to insult me at the same
time.

I try to exert due restraint, but I do not like your
occasional rudeness. (screwing light bulbs, etc.)

While some may be impressed by your style of (chemical)
name dropping...

 "To apply info pertaining to silver gelatin (however
impeccable it may be)..."

 it looks just like "name dropping" to me. (Anyone can
quote lists of names of patented hardeners.)

You said formaldehyde bonds are easily broken by
weak acids and heat.

I said I did not recall getting the interpretation from
the literature that formaldehyde bonds were so weak and I
was curious as to why you did.

Nothing you have written ANYwhere specficialy addresses
this.

It is important to be accountable for what you say.

I said I would reread the gelatin chapter and I did.

So Ryuji, can you tell me from what part of "The melting
point of such* a layer will be higher than 100 (degrees)
C." convinces you that formaldehyde bonds are, to quote
you "... not very stable, and they can be broken with weak
acid or high temperature." ?

??????????????????????

Perhaps I skipped a line, a page or two?

Perhaps you should concern yourself less with impressing
others by reciting long lists of chemicals you have never
used, ("chemical name dropping") and more with presenting
clear, factual and referanceable information.

You wrote:
"...literature in 1970's shifted to the mechanism of
hardening with glutaraldehyde, because this mechanism is
different from that of formaldehyde or glyoxal."

You mentioned cyclic linkages... (they were in fact at
that time conjecture...) however in the same James'
paragraph it also states that those links do not seem to
account for the great stability of collagen -
gluaraldehyde cross-links.

So what were you saying?

If another book told you something different, why don't
you quote that information?

You wrote:
"You really need to see literature from late 70's to get
any details on glutaraldehyde hardening mechanism. For
example, books from 1960's (like Zelikman and Levi,
Duffin...."

Easily done. All on my shelves.
On what page does it say formaldehyde linkages are "...
not very stable, and they can be broken with weak acid or
high temperature."?

> > I do not see why you are knocking
> > formaldehyde on the basis of its cross links.

> For silver gelatin process, formaldehyde has more
> direct disadvantage like tendency to fog, reduce speed,
or both, especially in fast emulsions.

Ryuji, all I am asking is for you to back up what you
claim, and back down when you can not provide supporting
refs. or personal experience of a relavent nature.

Is that too much to ask?

You said the bonds were weak.

I belive that is misleading.

As Sandy has pointed out, chrome alum is
sufficient for many procedures and in my opinion, for
reasons stated above, you are misguided and your recitals
are misleading.

Ray

--------------------------------
"Rivals make such good noise"
     Ray Rogers
--------------------------------
* "The melting point of such a layer [10 to the minus 4th
power) mole formaldehyde per gram gelatin] will be higher
than 100 (degrees) C."

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Received on Wed Feb 11 00:19:49 2004