On Jul 13, 2006, at 8:33 AM, Katharine Thayer wrote:
>
> And my own tests show something different from what either of you
> are saying, I think... my own tests show that it doesn't matter if
> the gelatin has been boiled, as long as it's relatively cool when
> it's applied, and furthermore applying the size while hot may only
> be a problem with some papers. Arches papers, which are internally
> sized in a gelatin bath, go speckly on coating with gum if the
> temperature of the sizing was over 140 when applied, IME. But if
> the same too-warm gelatin is cooled to 140 and then applied, no
> speckles happen. I suppose that what happens is that the too-warm
> size partially melts and disrupts the internal sizing, affecting
> the behavior of the paper. I haven't tried this with papers sized
> with non-gelatin material, but from reports that it's not a problem
> with such papers, I am willing to tentatively conclude that this
> isn't a universal problem, but only affects some papers, most
> likely those with a factory gelatin size.
Sorry, world, these temperatures are Fahrenheit and I should have
specified such.
Katharine
Received on 07/13/06-09:44:21 AM Z
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