Re: Another PVA question

[phritz phantom <phritz-phantom@web.de>]

keith,
yes, i think the pva stays put, but the exposed gum has trouble adhering 
to the ground.
when i tested the pva on wood (i think there was an acrylic primer 
beneath the pva, iirc), the image (single, first layer in yellow) looked 
fine at first, but the a gentle stream of water swiped it all off. it 
did not dissolve, but sheded off like a thin skin. i've never seen this 
with gum either, only with carbon.
the dilemma is that single layers develop beautifully and can even 
withstand a gentle stream of water in development (which is not always 
the case with gelatin sizes). i just can't put another layer on top. 
smoothing the red layer rips chunks out of the yellow layer, the more 
brushing, the less image stays on the layer beneath.
btw. i tried adding calcium carbonate (marble dust) to the mix (in a 
1pva + 1cc ratio +5water ratio). the outcome was horribly stained and 
ugly and the adhesion of the did not improve much.
the paper i used was one with a very smooth surface.

regards
phritz


Keith Gerling schrieb:
> phritz,
>
> In my case the dried layers are very sturdy while applying more gum,  
> even with vigorous application.  It is after the print has soaked that 
> the gum gets soft.  This goes against everything I have seen with 
> gum.  Usually, if you get a good hard layer of gum, nothing short of 
> bleach will soften it.  The strange thing is that the gum seems to be 
> affected but not the PVA.  Case in point:  Over a layer of yellow I 
> coat red.  Not used to PVA, I get sloppy and let an air bubble leave a 
> red mark undeveloped.  Put the print back in the water, but when I 
> take it out there is red pigment where the bubble was.  I brush away 
> the red (didn't need it there anyway) and the yellow comes with it.  
> Later, I apply blue and it develops fine.  No staining where the 
> blemish is.  As if the PVA was still there.  So why did the yellow get 
> soft?
>
> keith