Re: Gum problem(s)

On Sat, 19 Nov 2005, Katharine Thayer wrote:

>> You must read Kosar with the understanding that certain observations may no
>> apply equally to all colloid processes, which has lead many
>> to suggest that the book is full of errors. On the whole I think anyone
>> interested in any of the dichromate based processes would find Kosar
>> interesting, and perhaps useful.
>
> Yves,
> I don't know who the "many" are who say that Kosar is full of errors; I only
> know of one. . As I leaf through my own copy, I only find my handscribble
> "Wrong!" in one place, where he says "The idea that the dichromate ion might
> act as a photosensitizer was first proposed by Galinsky on the grounds of
> observations made by Brintzinger and Maurer" and my objection was simply to
> the citation, not to the information that the dichromate ion might act as a
> photosensitizer. And the objection is miniscule against the information
> contained in the chapter. I certainly agree with Sandy that "anyone
> interested in dichromate based processes would find Kosar interesting, and
> perhaps useful."

Not sure if I'm "the one" Katharine refers to, but I've been more annoyed
than pleased by Kosar. For two reasons, firstly, NONE of it that I recall
is his own testing, it's all "so and so" claims that thus and thus "seems
likely" or "probably therefore" or "indicates," "suggests," or "we thus
conclude" and so forth. In other words at best it's a surmise at one
remove... and don't we know better by now than to trust "tests" IN ANY
MEDIUM where all variables are not controlled -- and all materials from
the same source?

Secondly, and much more worse, I didn't find any of it I can apply to gum.
The tests were all (as stated, and that I came across, tho I admit only
checking the seemingly relevant chapters) applied to CARBON printing, or a
derivative of carbon. Not gum. And no matter what they tell you, just
because it's dichromate does NOT mean they're the same. I mean just
because it's got gum in it doesn't mean a gum print can be eaten like a
gum drop.

The first time I came across this was when someone on the list explained
to me that gum has a straight line "curve" -- I should check Kosar if I
doubted. IME, anyone who gets a "straight line" curve as a rule in gum
printing can probably walk on water, as so rarely happens.

Thirdly, some good or evil fairy in this house has stolen my Kosar. Thank
goodness, dammit.

Judy

>
Received on Sat Nov 19 17:13:33 2005