TK asks:-
''Does this have any effect on the suitability of 'commercial' PVAs for the purpose of gum printing ?
The one( PVA ) I have here seems to work well enough.''
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Hi, We cannot see why TK is asking this question if he is quite happy with the PVA he is using to make gum prints. Perhaps he might tell us.......
John Grocott - Photographist. London.
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In a message dated 3/4/06 6:35:32 am, rs@silvergrain.org writes:
Furthermore, the alcohol groups in PVA is _secondary_ alcohol and so
they undergo usual alcohol reaction, such as oxidation. So alcohols
can be oxidized to _ketone_. Commercial PVA is likely to have
residual acetates and a small fraction of ketones made by oxidation.
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The one I have here seems to work well enough.
Terry ''
Received on Mon Apr 3 02:25:48 2006
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