Ink Coverage
I’ve been letterpress printing with my 10x15 C&P OS for a few months now and have finished about a dozen different projects. I’ve learned a lot about make ready, platen leveling, roller gauging, amount of ink, and so on. I’ve been able to get some pretty great results so far.
With that said, I’ve been running into one problem across all my projects: Lack of ink coverage. I’ve experimented with many different variables including amount of ink, roller height, impression depth and so on. No matter what I do, I haven’t been able to remedy this problem.
I can usually fix it by skipping one impression so the form gets inks twice or three times before printing - but this obviously should not be the proper solution to achieve a well printed product.
Does anybody have any suggestions regarding ink coverage? How can I black ink to print a deep, rich black in one pass on the press? Does temperature matter? Should I be thinning my ink?
I’m using Oil based ink. I’ve also tried vanSon Rubber based with the same results.
Thanks!
EDIT: A couple things worth mentioning: I’m using two new rollers on my press. I’m not using the third, lower roller. I’m primarily printing with polymer w/ boxcar base.
Depends on how much ink your trying to lay down, maybe you should try the third roller, if your ink and rollers are in a cold place you will have problems, bring your ink and rollers in the house and let them heat up over night and see if that helps.you could run an electric heater close to your press (that’s what i do in cold weather) good luck Dick G.
With just three rollers and an ink disk, a C&P has a very limited inking system. Double-rolling as you have already discovered is the easiest way to increase ink coverage. In the right circumstances a double hit can help. Mechanically, using an ink fountain will feed in controlled amounts of ink, and a rider roller will help distribution.
Doctoring the ink with reducer or ink conditioner may help solids print, but it won’t necessarily help typographic work. But bear in mind the paper itself has a lot to do with ink appearance. If loose-fibered cotton stock is soaking up ink faster than you can throw on, switch to a sheet of coated stock and look at the difference.
Thanks for the input and suggestions.
Today I did some printing a brought my ink and rollers in the house to warm them up. I also put a small electric heater on my ink plate to heat it up.
This seemed to help a bit - my coverage was definitely better. I’m wondering if most of what I’m dealing with is temperature.
Temperature will definately cause things to not work so good. Leave me out in the cold overnight and i don’t work so well. I leave the heat in my garage on about 55 degrees, then during the day i run a small wood stove to bring the heat up to about 70. Without heat metal will start to develop rust pretty fast, ink thickens, rubber rollers are forgiving but if you have composition rollers and they get too cold they will turn hard. Good Luck and stay warm, Dick G.
Just a follow up to my problems with ink coverage:
Even though I saw some improvements with warming the ink and ink plate, I still was not getting my desired amount of coverage. I thought perhaps I would experiment with make-ready in order to solve the problem.
It turns out, by sticking a sheet of packing above the press board, directly below the tympan paper, it allowed the coverage to improve considerably. I’ve always made sure my press board was directly below the tympan, but in this case, it worked much better to have a softer sheet of packing for a larger area of impression.
I was curious if anybody else modifies make-ready to accommodate a larger area of impression?
Definitely, when needed, letterpress demands more pressure on large solid areas, to be compatible at all in a mixed form of large solid areas and fine detailed things. If you want to experiment, try going to the party store, purchasing a balloon, maybe two. Any color will do, I would pick my favorite color (Purple). Take these gems back to the shop, blow one up for the son or daughter to play with. Take the other one and with a pair of scissors or the like, cut the outer edge of the uninflated item, maybe a quarter inch in from the edge. You now have two latex or rubber makeready pieces. Once your job is ready to print, and you have trouble covering a large solid area, remove an amount of packing right under the solid area that is causing the difficulty. and paste in a piece of your new found treasure. CAUTION: a bit of experimenting may be in order to find what will adhere it to your undersheets of packing, so it will remain in place. Good luck, have fun. Suggest doing this on a job that is an experiment first and not depending on it until you feel confident you can hold it in place. I am guessing the thickness of the latex to be aprox. .030 caliper. You also may find that the top sheet has to be replaced on a long run as it is being forced to flex, and paper does not like to do that for an extended period of time.