Re: acetone

On Dec 22, 2006, at 5:20 PM, Witho Worms wrote:

> Dick,
>
> More than a month ago I wrote to the list with a question about a
> 'melting'
> top layer of tissue while sensitising.
>
> (We just stopped when the pigment started to come off the tissue.)
>
> Can you tell me more about this.
> - - - - - %<- -- - - - - -
> With a flooded brush method I believe there is a time/temp
> parameter. Last
> summer when the print room was in the mid 90's (that's Deg F, not
> Deg C.!)
> there was virtually no time/temp control. We just stopped when the
> pigment
> started to come off the tissue.
- - - - - - %<- - - - - - - - - -

The problem was that the room temperature was above the set point of
the gelatin. Low to mid 90F. Even with chilled sensitizer in 2
minutes or so there was black being picked-up by the foam brush.
Gelatin was dissolving. Had to go to a short sensitization time and
also use a tray of ice to weight the tissue and final support during
mating.

Just goes to show why the old timers were wise enough to not print
carbon in the summer. Far wiser to sit under the shade of the portal
with a cool beverage of choice.

Howard

PS Have a great holiday season and a new year where your prints do
not bubble or frill!
_______________________________________________
Post to the list as PLAIN TEXT only - no HTML
carbon mailing list
carbon@spitbite.org
FAQ at http://spitbite.org/carbon/list.html
Received on Fri Dec 22 18:02:23 2006