U of S | Mailing List Archive | alt-photo-process-l | Re: polymer plate drying time

Re: polymer plate drying time

Keith and Jon,

After all this talk about drying time and such, this morning I exposed
and developed a test strip then skipped the hairdryer stage and went
straight to the oven set at 100 degrees.  I figured a few minutes at
100 to dry it, then bump the temp up for a few more minutes as per
Keith's Toyobo instructions.  Well........... after 10 minutes I
checked it, and it had bubbled and kind of melted in all the darkest
areas!  There are also larger (pencil diameter), flat bubbles in the
mid to light tones that appear to be the polymer detaching from the
plate base.  The plate didn't get that warm... when I took it out of
the oven it was just a little warm in my hand, not hot at all.  SO....
it appears that the moisture in the polymer needs to escape more
slowly than the 100 degree oven allowed.  Also I would speculate that
since those deep bubbles occurred, separating the polymer from the
base, there was moisture down at that level that became trapped when
the top layer dried more quickly.
So as usual, haste makes waste :o)   we need to be sure they have
sufficient drying time before any heat curing, and I'd suggest testing
the heat thing before trying it on something important.  I'm going to
go re-do this now and I'll report back.


On 3/15/07, Jon Lybrook <jon@terabear.com> wrote:
This is best piece of info I think I've gotten since starting the use
the KM73s.  Thank you so much for pointing this out Keith.

Do you suppose drying the plate after post-exposure would have the same
effect?  I'm thinking about plates I've already got but haven't printed

I'm probably overdoing the post-exposure.  5-10 minutes was generally
recommended for Solarplate -- which is why I was doing that.  I was
post-exposing for 20 minutes in the hopes of eliminating those
scratches.  It didn't though.  I can't see doing a post-exposure for the
the time of my screen/image plus some like you do though Keith.  That
would only be less than 30 seconds for me!  I think once the plate
becomes the nice blue-green hue as opposed to the light green it's
probably good to go though, don't you?

The new Toyobo plate sounds like something I should certainly try as
well...especially with the finer dot screen I use.

Between the new plates, the new 4800 printer I'm considering, and the
subsequent ability to start using rolls of new Pictorico Ultra film
there's a ton of changes and improvements in store for my process this year.

This list rocks!!!  Thank you all for being there.


Keith Taylor wrote:
> On Mar 15, 2007, at 11:50 AM, SusanV wrote:
>> Keith...
>> you said, "Toyobo even recommend 5-15 minutes at 122-140 degrees
> Susan,
> I have a sheet from Toyobo that came packed with the plates ages ago.
> I tried to find it on both Anderson and Vreeland and Toyobo's
> websites, but the AV link was bad.
> I did notice however that Toyobo have a "new" plate out designated
> Printight DF. It's apparently capable of resolving 200lpi
> (KM73=150lpi) and detail in the 1-95% range (KM73=3-95%). The Shore D
> hardness is 55 whereas the KM73s are 67, which means the DF slightly
> softer.
> On Mar 15, 2007, at 1:24 PM, Jon Lybrook wrote:
>> Wow.  This is really good info Keith.  Maybe this is why I have issue
>> with scratches, eh?  Didn't you say scratches weren't a huge problem
>> for you at one point?
>> So you dry before post exposing? When post-exposing for 5-10 minutes
>> under my Olec unit, it actually gets quite hot...so maybe that's why
>> I haven't had more major issues.  Perhaps the post-exposure also
>> functions as what you and Susan are calling 'dry time'. What do you
>> think?  Should I bake my plates in the oven after processing before
>> post-exposure?
> Jon,
> I'd certainly dry it longer, even if it's just with a hairdryer and
> no, I've never had a problem with scratches. I can (and usually do)
> wipe quite hard with tarlatans.  I have a 5KW lamp that also gets
> quite hot but noticed recently that you post expose way longer than I
> do - this is probably why!
> My workflow is to expose the plate, dry with newsprint immediately,
> then dry for 2-3mins with a hairdryer. Next, I dry it for a further
> 5-10mins in a drying cabinet on high heat. The post-exposure is
> normally a little longer than my combined screen+image exposures.
> Of all the problems I've had, scratches have never been one of them.
> So I think you'd only benefit from drying a little longer.
> Keith.

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