screen printing advice

[Anonymous]

anybody have any advice on screen printing? i've done a couple series and t shirts. mesh counts, exposing screens, registration, ink types, anything like that...?

[lure]

i'm sure you'll get some input through this thread, but there are other threads here about screen printing. sift through the forums and you'll find some info.

[seripop]

what exactlly d'ya need to know?

[Anonymous]

i guess most of my dilemma involves shooting screens. i usually wind up sending them out. i need a good system of exposure... 300 watt bulb, how long? any specific emulsions better than the others? if i put everything through photoshop and print the seperations on acetate, what dpi should i use for the halftones? are the peel and stick emulsions any good? is 130 mesh count the best approach? any advice would be greatly appreciated.

[Anonymous]

for burning screens i use 2 [or 4 for larger screens] 125 w flood bulbs[usually for outside your house] that you can buy at any hardware store. i attach both to a mic stand approx. 4-6 inches apart and then move the neck of the mic stand over the screen about 15 inches above the screen for 15 minutes. i find that this works every time.

when i burn my screens i always place a piece of glass over the transparencies so they stay in place and i find that the diazo emulsifier works the best so far.

right now all of the screens i'm using have 110 mesh which seems to work ok, but a higher mesh count will give you more detail.

hope some of that helps.

alanna//

[Platinum Rich]

your screen-printing questions are all pretty basic so looking at a few books could help. 110 mesh is great for shirts but kind of coarse for posters. you may see some saw-toothing (jaggies) around the edges of images. a finer mesh will clog faster if you're using water-based inks and won't lay down as much ink as 110 mesh but the resolution is better. to do halftone dots make sure you have proper contact between your positive and the screen. you're gonna need pretty huge dots for 110 mesh. ulano makes a wide range of emulsion and it's cheaper to buy a big bucket. the emulsions vary depending on light source, ink type, etc. buy an exposure calculator to determine the exposure time. make sure the black on your acetate is very opaque our your film won't work. i could go on forever but getting some books, reading articles on the web and experimenting will serve you better.


<font size=-1>[ This Message was edited by: rich on 2002-03-16 07:49 ]</font>

[Anonymous]

thanks...that clears up a lot. i guess just need to make a mess and expirement a little more.

[Platinum Rich]

the other thing you'll realize, like most things, each person has different methods and opinions. you just gotta find what works best for you. start with the similar methods and go from there. experimenting is part of the fun. because of that, my work has a very distinct look from the way i print. now go print some posters.

-rich

[Anonymous]

what is a good dpi if i seperate colors in photoshop on a 130-150 mesh screen?

[drowningcreek]

To do your seps out of photoshop, start by making your art at 300 ppi at actual size. It makes for a large working file, but it will cut down on the "jaggies" that appear when working with lower resolution files.

I print with all kinds of mesh and inks. When using metallics with a pigment size larger than 25 microns (it's in the spec sheets for each pigment) I use 110 mesh. You do loose some detail but the ink coverage is much better. I tend to use 180-195 mesh screens when applying regular color and 230 for my black and very detailed colors.

I also use solvent based inks (Nazdar 5500 series) and have found that by reducing the inks by as much as 30% with retarder thinner that I have less clogging problems on press. Metallics with a coarse grind ALWAYS will clog to some extent, but the key is constantly working them on press and swabbing the detailed image areas upon the first sign of a clogging. The old phrase "an ounce of prevention is worth a pound of cure" definitely comes into play here.

One other piece of advice, always premix enough ink to complete a run. I have under estimated the coverage of a color and wound up trying get ink mixed while the press is waiting...only to have to completly swab down the entire image area and clean it before starting the run again. All of which could have been avoided if I had just had that extra bit ink ready.

As far as lights....a simple flourescent bank made from 5--2 bulb 48inch shop lights mounted on plywood with a sheet of quarter inch glass mounted on 8 inch pegs above the platfrom (on the corners) works great as a starter exposure unit.

you simply tape the art to the glass, place the screen on top, and then place another piece of plywood covered in felt (cut to the interior size of the screen with a small handle mounted on back to lift it after exposing) in the screen and weight it down with a bag of lead shot that you can get at any store that sells reloading supplies for hunters who make their own shotgun shells. This will keep the screen snug against the art. Then buy a $10 dollar cooking timer and you're ready to go.

Total cost of the unit should be about $100 dollars..or cheaper if you scrounge the parts.

After the screen is exposed and the image washed out, blot it with newsprint and if you have access to an air compressor, blow the remaining water out of the image area and screen frame edges. this avoids residual emulsion creeping into washed ares and reblocking the screen. This can be a major pain in the ass with halftones.

Hope this helps...feel free to write me with any more questions...I'll be glad to help.

Jeff@drowningcreek.com