U of S | Mailing List Archive | alt-photo-process-l | Re: Newton Squashed Under Pressure (photogravures)

Re: Newton Squashed Under Pressure (photogravures)

SusanV wrote:
Hey Jon,

The reason I'm so sure about this is that the other day when drying a
plate I noticed a flaw, so I looked at the hardened plate with a 10x
loop under really bright light, and there they were... the same little
mottled areas I see on my prints.  They were on the plate, no doubt.
They are actually little squiggly lines.  The Newton rings aren't
round rings at all... they are irregular in shape and as they all
bunch together as they shrink under vacuum they form those little ...

Bundles of joy, eh? I've never heard of this. Newton Ringworms...

These are the same squiggles you were referring to in your step test on your blog, right?

As for why I could use less pressure... I'm getting good results with
what I consider moderate pressure for intaglio... except for the
darned squiggles.  I changed to harder blankets and cranked the press
down tighter, and it got rid of the squiggles.  It's just pressing so
hard that it's eliminating them in the press.  Without the marks on
the plate to begin with, I can go back to less pressure and my regular
blanket setup.
If it's on the plate, it's sure to wind up in the print. I'd think more pressure would make any aberration more pronounced, not less. Where do these squiggles occur - in light tones only or all over?

If it's not blanket noise or lack of pressure that's really causing this, I wonder if all my plates have it too? Once I realized cranking the pressure solved the problem I stopped investigating. Now that Keith's trick has my plates more durable I'm not as concerned about too much pressure -- but it would be nice to go with less for sure.

As yet another mystery unfolds...