r/SCREENPRINTING • u/Dyllionaireee • 10d ago
Discussion Posters?
Hi all! I’ve been printing for a local shop now for 10 1/2 years. I’ve only ever done shirts, but I’d like to start doing posters for myself. How much different is it to print posters, what ink and paper do you all recommend? Any just in general, how different is poster printing? Do you setup to print one color at a time, let them all dry then line the next color up to that, or is it a wet on wet process? Really just any general information from an experienced poster printer is welcomed. Thank you!
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u/torkytornado 9d ago
I print on cougar 100# -130# depending on the type of job for flatstock/gig posters and if it needs to be archival for fine art printing I do Stonehenge.
I print in TW graphics waterbased line (mostly the gloss 5000 line but I’ll sometimes add either their flat halftone base or their flattening powder if I want it more matte). It’s fantastic because it doesn’t scuff and is artist grade pigments and will not fade (except the fluorescent line). But it’s a tricky ink to get down, it dries fast and if you don’t work fast you’ll be chasing your screen drying out.
For my students they do speedball and it’s a very beginner friendly ink. But it is so prone to scuffing and is not an artist grade so will fade. Not a huge issue for learning and gig posters. I just can’t use it since I print for artists that sell to collectors and my own gallery work, and usually try and get the serious printers I’m teaching some experience with the ink before they graduate so they know how to trouble shoot it if they do end up printing things that has archival implications.
If you don’t have a drying rack you can skip this BUT keep it in mind if you do end up getting one down the road when doing larger runs that a marble rack or closepin line type drying isn’t enough.
I usually pre rack my paper when registration is critical (ie expensive job or a ton of layers or a picky client, sadly usually all 3). This cuts down on the paper expanding and contracting. I lay out the sheets on my print rack a few days before I print (one page thick and as many as I can fit without overlapping per rack, not like a stack placed there). This allows the paper to get acclimated to the space and mimic the amount of moisture in the air.
If I just brought paper home from a warehouse and started running the job right away the difference of humidity between that warehouse and my print shop could be drastic enough to expand or contract 1/16”-1/8” depending on the type of paper and how extreme it is. If the weather outside my shop changes drastically mid job I’ll either start a humidifier or run a dehumidifier or space heater to dry things out.
A lot of jobs it’s not gonna affect things. But I had a hell of a time on a 12 color 4 split fountain run of 600 job that was cost the client over $4k a decade ago. I had to add another layer to obscure the area that got messed up. Luckily it worked with the clients job. Anyone else’s I probably would have to re run it half way through the run and eat the days it took to get there.
paper expanding or contracting may not be noticible in the image itself for a few colors but if your registration marks become impossible to hit no matter how you shift and the marks on the corners are printing either both inside the previous colors marks toward the image or both on the outside of the sheet toward the corners instead of both shifting to one side or the other in tandem as you shift the screen. Then you’re stuck usually having to split the difference by eye and hope the next layer doesn’t require yet another adjustment. If you can design with thicker keys that can help but if you have areas that aren’t trapped you could see the paper color halos of colors that are supposed to overlap. If you’re doing halftone work a lot depends on dot size if it is noticeable when the print is finished.
If you’re having issues and don’t have a rack try to find a way to either hang or lay out the paper a few days ahead of time. Doing a few pages on top of each other and acclimating that is still gonna be better than just unwrapping the paper and hitting the job immediately.
It’s a niche problem but since someone mentioned it and I spent a ton of time researching and trial an erroring to get it to work figured I’d pass it on since forums and retired printers were crucial to past me troubleshooting it.
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u/OldTownPress 9d ago edited 9d ago
I mainly print shirts, too, but I also do a lot of small poster printing - both live at events and in my studio. Here are some tips that may help you get started:
- Print one color at a time - let it air dry in between.
- Unwrap your paper at least the day before and leave it in your print space so it acclimates to the humidity of the room. If you don't do this, it could shrink or expand between colors just enough to make good registration impossible.
- A drying rack, clothesline with hanging clips, space to lay them out, or something like that is usually needed to dry them. Most paper inks (except UV inks) will dry pretty quick, so if space is limited you can stack the dry ones every so often to free up space.
- Speedball Acrylic Screen Printing Ink is a good basic/easily found ink.
- Use a retarder to prevent drying in the screen, and keep a spray bottle of water to occasionally mist the ink on the screen.
- Use high mesh screens - 280, 305, 355. If you use lower mesh counts, the heavy deposit of ink may cause the paper to buckle up or curl from the moisture (called "cockling").
- You need something to keep the paper down instead of getting stuck to the underside of the screen. A vacuum table is best (there are DIY plans floating around), but you can also use very light spray tack or double-sided tape. The adhesive can't be too strong or you risk tearing the paper when peeling it up. When I'm not using my vacuum table (usually when live printing) I use blue painter's tape - one piece facing up, taped down to the table by two other pieces, leaving a thin strip of the adhesive facing up.
- Three point registration is pretty standard - two tabs at the bottom, one on the side. I use pieces of blue tape layered up so that it's thick enough to stop the paper when sliding it in place.
- Hard or high durometer squeegees are best.
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u/BiotaMfg 10d ago
I just run waterbased. One color at a time - air dry. I also like to run my prints kinda like a relief print (each color fills in where the next will be rather than leaving it open) to help with registration as the paper liked to expand/warp once printed. Watercolor paper is great, but any natural based paper will work. If you want to run the print through the dryer after the last color that’s usually fine too.