Re: 3rd layer of gum

[Katharine Thayer <kthayer@pacifier.com>]

Paul, I've only seen this with nonabsorbent surfaces like glass and  
yupo, and only in areas where there are actually three layers of  
hardened gum. (for instance if there's an area that's all blue, where  
little or no yellow or red pigment have been deposited, there's no  
problem with adherence of the third (blue) layer, only in more  
neutral  and mixed areas where there are equal amounts of all gum  
layers.  I've never seen it with paper.

As Keith said, you can adjust for it either by exposing more or  
developing less.  I also wonder about your sizing; it sounds like  
maybe your sizing isn't leaving enough tooth for all the layers of  
the gum to have some to hold onto.

FWIW,
k


On Oct 6, 2009, at 1:18 PM, Paul Viapiano wrote:

> Hi all...
>
> Why does the 3rd layer of a gum print always develop so quickly, or  
> is subject to washing off so much more quickly than the other  
> layers, whether with sized paper or not...? (regardless of printing  
> order, as well...and these are all the same exposure time, too)
>
> This has happened on several tricolors I've done now...
>
> Thanks!
>
> Paul