What is the protocol on perforating or scoring with photopolymer? I imagine scoring wouldn’t be a problem, but I wasn’t sure about perforation or how many dots per inch a line should have for a proper perforation.
I know typically metal perf rule is used but I can’t seem to find any. I DO however have some 6pt rule which I was planning to use for scoring, but I haven’t gotten the opportunity to try it out yet. It’s probably a bit too thick and should be used for its intended purpose - printing rule. However I have it and was just curious.
Log in to reply 14 replies so far
you need steel rule for perforating and scoring, when you score you need to use matrix to get the best score, when perforating you need a backing to keep from damaging your press bed. if you use lead rule it will wear out rather fast.
I have a ton of perf rule if you would like some, just send me an email! I use matrix most of the time for scoring, but on my Golding Map press I can use a 1pt line photopolymer that works well if I am doing something small.
What could I use to protect my press bed/ tympan? Could I just get a thin sheet of metal and put it behind the packing?
Also, In my searching I found this thread helpful so if someone else stumbles onto it they can see this too:
If you were a commercial letterpress concern, meaning, if you were real industrial high end and could afford it and had the continual need for it, Bunting Magnetics can supply bases and plates for die cutting, foil stamping, embossing, etc., even perforation. You don’t want to go there.
Otherwise, no, your basic photopolymer plate/base issue can’t really cut the mustard.
To protect the platen/ cylinder it was common to use a brass plate under the typhan for platen presses.
On cylinder presses you would need a steel jack for the specific press to mount on the cylinder.
Thanks all, My mentor says he only uses photopolymer to score on cylinder presses. (I think I head him say it before and that’s why I remembered it recently). He’s mostly a book maker so I doubt he was scoring anything heavy. I think I’ll try making a 2pt matrix out of photopolymer and test it myself. I’ll report back after I test it out on a few different weights.
I’m also planning on testing the viability of acrylic as a photopolymer base -we shall see how durable it is. You can’t beat the price of 13 dollars for a .6”x6”x5”. With a shim it may be viable and if so, getting it custom cast from one of those ‘acrylic awards’ places might be a fine option. If that works I’ll make a video and post it.
Peter Luckhurst some months ago said try out those nylon? cutting boards for kitchens-I bought one and will try one day…….have used acrylic in intaglio presses(more pressure?) and eventually will crack up, shatter.
Thanks for the heads up, that’s the sort of stuff I’m trying to find out. Eventually I want to get a proper alum base, but maybe in a pinch these acrylic ones can be used every once and while or for a kiss impression. I do think eventually they will crack, but even if they only last 6 months a piece - it will still be cheaper than a boxcar base of the same size for 7 years!
I’ve printed a few projects with the makeshift acrylic base, and to be honest it’s working great so far. Kind of goofy looking. I had to tape three reglets to the back, but it brings it up about .002 under the deep relief base height which hasn’t caused any problems so far. Easy, consistent prints and the lockup is the same. We will see how long it lasts, but I haven’t noticed any quality difference between this base and the aluminum so far. Once again, these can be bought at Michael’s craft store for about $13 with one of their weekly coupons. I think those are 6pt reglets for anyone who is curious (have to check). Printed probably about 700 impressions - both kiss and med/deep impression in cotton and hard stock.
If it fails, cracks, or causes problems I will update again.
P.S. I printed with it using just a vertical lockup and with a chase lockup. Both printed fine. Wouldn’t use just the vertical lockup for multiple colors for obvious reasons.
A print using the base
I should also mention, I’ve printed a two color line up, and printed using an image that covered the whole base, and as above some very small bits of photopolymer. Tested both text, and images. No issues. I made sure to space the reglets to ensure even support.
The reason I think acrylic typically cracks in Intaglio presses (I’ve used it that way before) is that the pressure is not even. As it goes under the roller the pressure is high in one area of the plate - not over the whole plate. This base is 5-7x thicker than anything I’ve ever seen used for intaglio and the platen press ensures the pressure is more evenly dispersed than it would be with a cylinder or intaglio press. My assumptions.
yup, intaglio presses can be 1-2 tons very concentrated pressure.
We did a German bell as a holiday card a couple of years ago with photopolymer plate. Two runs of color and one of blind debossing for the score done on a Vandercook with very soft packing to get good impression on the score. Worked great.
Don’t forget, if you score for a fold, you are supposed to do the fold opposite to the way it was scored. This stresses the paper fibers less.