11942Re: [PPLetterpress] Re: Photopolymer separating from polyester backer
- Aug 1, 20105 minutes shouldn't be too long for the washout. You're fine there.What type of platemaker do you use? Point light source or a bank of lights?The photopolymer will separate for lots of reasons. It sounds like this is happening during processing? During washout or during drying?Finally, are you using silver emulsion film? It sounds like you are. Just checking.Would love to help but need more info.Harold
On Sun, Aug 1, 2010 at 11:09 PM, idgradstudent <glenwoodemorris@...> wrote:
Fresh KF95 plates.
I have a lot of "variables" like oldish brushes, and older bulbs that require a long exposure time (9 minutes according to my stouefer scale). So it would certainly be easy to dismiss my issues by saying "Hey, go do some basic maintenance to your platemaker" and you would be right. Aside from this relatively recent issue the plates have been good so I have opted to spend funds on other more pressing issues as a longer exposure time does not cost me much since I only make plates for myself and the cost for new bulbs and ballasts is not insignificant.
My washout is probably too long (5 minutes), I will back it off and see if that works. When I first acquired the machine I established my exposure times with a scale and my washout times through trial and error but I may have just gone too far. Generally if I lose anything to this problem it is a crop mark on the edge of a plate, but recently I started losing thin script text and fine lines in graphics if they were also near the edge of the plate.
My question included limited info as I wanted to know what the root cause of photopolymer/polyester separation was rather than have folks just tell me to do maintenance that is not really an option right now.
Oslo Press Inc.
--- In PPLetterpress@yahoogroups.com, "idgradstudent" <glenwoodemorris@...> wrote:
>> I did some searching and found several discussions about plates that have separated; i.e. the photopolymer has detached from the polyester backer.
> What I did not find in the discussion was any agreed upon conclusions about why exactly this happens (or I simply missed it).
> Does anyone know what causes this to occur? I am currently having problems with this with some of my plates and was wondering if there was a "known cause" before I just start changing things and hoping for the best.
> Glenwood Morris
> Oslo Press Inc.
501 W. Fayette St. #222
Syracuse, NY 13204
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