Re: Counters not washing out
- Hi Casey,
I have not worked with polymer plates that involve back exposure, but it
sounds like over-exposure to me. For my steel-backed plates, the washout time
is critical only when it is too long - when the time in the water allows
the base of the polymer to absorb too much water and thus allows the
hardened surface to separate and move or break off. More time in washout does not
dissolve material that has been hardened.
Too much exposure time, however, will harden more of the base and can fill
counters or white lines in a reverse image, because the base material
swells out from the face of the exposed image as it has time to harden more of
the base polymer, as the UV light continues to penetrate indirectly to areas
normally protected by the negative - the surface of a letter will look
correct, but the sides and counters will be swollen if it is over-exposed.
Could be emulsion density, but it is possible to work around even weak
emulsion by under-exposure.
Tom Parson/ Now It's Up To You
157 S Logan, Denver CO 80209
(303) 777-8951 home & printshop
(720) 480-5358 cellphone
In a message dated 9/13/2009 8:20:14 A.M. Mountain Daylight Time,
I don't have way to check the density of the film an the film output
bureau has been pretty consistent. I'll ask on Monday because this maybe the
problem. The longer washout helped but the counters are still not open enough.
[Non-text portions of this message have been removed]
- From what I am reading of this thread, I can only conclude that there are
many people out there who are using photopolymer on a daily basis. This
leads to the common practice of developing a procedure which works. The
problem with this practice is that things change which you are not aware of.
I do not work much with film today but when I did the slightest change in
any of the steps could cause major changes in the outcome. Film, developer,
water, as well as environment can have a major impact on the total process.
I would suggest that even though you are getting your negs from the same
service, it is highly likely that they have changed suppliers or their
supplier may have changed their supplier. All of the other things involved
should be considered one at a time.
When a procedure works then stops working it is sometimes difficult to
remember how the procedure was developed. It is just done by habit and you
don't remember why some of the steps are important or how you came up with
I am just suggesting that the procedure be revisited and considered step by
step and make no assumptions. Only make one change at a time to eliminate
I know film processing is an art which has been mechanized to the point that
no one needs to make note today.
I hope this is a help in finding the cause of the change.
prints by AJ
----- Original Message -----
From: "cmcgarr1957" <casey@...>
Sent: Sunday, September 13, 2009 10:19 AM
Subject: [PPLetterpress] Re: Counters not washing out
> I don't have way to check the density of the film an the film output
> bureau has been pretty consistent. I'll ask on Monday because this maybe
> the problem. The longer washout helped but the counters are still not open
> Yahoo! Groups Links
- Thanks Austin, very good points.
I visited with the film output business and their densities were light reading around 2.5. They output new film and I'm back in business making good plates.
Thanks for all the recommendations everyone gave me.