Re: The consistency of gum

On Tue, 2 Dec 2003, Katharine Thayer wrote:
> My findings re Daniel Smith standard gum are different from those
> reported here by others; my findings do not disprove the other gum
> printer's findings but just add more data. I suspect it's the lights
> that make the difference between how this gum prints for us, but who
> knows.

I have the impression that these bottled gums change from year to year, or
with each new lot... That said, I haven't tested more than 2 of the DS
regular gums, because I found one I liked & bought another gallon of the
same lot, which i'm still using.

However, I'm curious about the finding stated below that the powder-made
gums have a longer scale. Can you state some numbers for comparison? Is
it possible it's not the powder vs. the pre-mixed *per se*, but the fact
that the % or some other attribute is different?

J.

> > Slight clarification: I'm testing 5 gums mixed directly from powder and
> > one dark lithographers' gum (daniel smith's standard gum) All six are
> > about the same consistency and coat about the same; they "work" about
> > the same is what I was trying to say. But it wouldn't be accurate to say
> > that they all print similarly. The differences between the five light
> > gums are very small, so small that when I run the same test several
> > times, different gums come out on top each time. This is to say that
> > statistically there's not much difference between them, and I'll need to
> > run more tests to be sure that the small differences I think I see are
> > real. But the lithographers' gum is very different from the other five
> > in the way it prints. It clears fastest, although they all eventually
> > clear completely within a reasonable development time. But more
> > problematic for me, it prints significantly fewer steps than the other
> > five, and the steps are very distinct from each other in tone. This
> > makes a really pretty step test, but a bad gum print from my point of
> > view. It may be just what someone else wants, but too jumpy for my
> > taste; I want much more subtle tonal gradations. This is such a
> > consistent finding that I feel confident to report it, while the
> > differences between the other gums I'm not so sure about.
> > kt
>
Received on Wed Dec 3 01:24:07 2003