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screen printing => Waterbase and Discharge => Topic started by: ScreenPrinter123 on February 11, 2013, 05:20:21 PM
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We have been testing the CCI system and are ready to start using it on jobs but Brian and I are struggling with comparing discharge prints to plastisol prints. We have a job to print this week (teal and white on a delta apparel purple shirt) that I would like to use discharge but I first wanted to get your feedback on judging whether a discharge print is acceptable in comparison to how it would look if printed with plastisol.
How do you rate opacity when using pigmented discharge because next to plastisol it seems to be second rate since it does not have the pop/shine of plastisol. The difference becomes more noticeable because plastisol often fills in the weave of the shirt and thus can hide the weave pattern of the shirt adding to the prints apparent vibrancy.
I have attached a picture where the bottom teal is a pigmented discharge using CCI products on a purple Delta shirt (with a print print through 180S; ignore the cracked texture as there was a screen further down on the press that had poorly applied tape underneath that caused that pattern). The pigment did not match the plastisol top print above it but I think with adjusting the formulas we can get closer. Would you go with the discharge or would you print a DC base with plastisol on top?
Do you discharge gurus assume going into it that discharge printing will yield results that by nature will look different than plastisol. If so how do we best explain this to our customers who until now have only received plastisol prints.
Thanks!
Michael
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Purple is not a good one to try and match with. We just explain that they are two different processes and that there will be a difference in color especially across color ways of garments. They do not react the same therefore you will get a different color variance. If it is customer that you need to play it safe with run the plastisol. If it is one that is questionable you need to take your time and explain the differences and what they could expect. You also need to test, test, and test again to get comfortable with what your results may be. Even then they can can still throw you a curve ball with dye lots.
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Purple is an iffy color to discharge to begin with, are you getting a full discharge with the garments?
For iffy colors we discharge underbase.
And you are correct in the difference between the two inks. Waterbase will never have the plastic shine,
but for nearly all of our clients, that is preferred. Even construction companies and the usual bulletproof crowd
prefer it as it breathes.
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I've actually had an ok time discharging purple so far. Not the best but better than dealing with an overdyed lot of black Ts.
Try tweaking first, you aren't too far off, but if you hit a wall, that DC UB + plastisol looks fine to me too.
Tony mentioned using a heat gun to quick test and what a great help that is, saves all that time waiting to see it cured at back of the dryer so you don't lose your momentum. You gotta keep that momentum up when mixing colors by eye, at least that's how I feel about it. Bonus- you get to watch it change colors which is neato but try not breath too much while doing it.
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I can say that the Delta purple discharged significantly better than the PC61 we tried. I will give the heat gun a shot as I could not get a blow dryer to work very well. For this job we do not need an exact pms match, I guess we will just have to get used to the difference in the way a plastisol and discharge prints looks.
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A good representation of the art is what I usually tell them to give yourself some wiggle room. Same with the PMS matching. Like Zoo said that purple turned out pretty good. Better than most purples.
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Looks like, ironically, it just needs a splash of white.
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Purple? Damn, must be getting late for me or I need to get my eyes checked. Thought that was Royal! Anyway, as you noticed there is a difference between the ink types. We have clients that come from other print shops and once we educate them they almost always go for water base. And if it is a big run with a lot of real estate being printed on the shirt I always push discharge to make the run go as fast as possible
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I'll respond later my back.........is...........killing .............me
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Medkicking in thank God. OK......yes purple shirt is a bad start. The blue dye #2 used to make most purples, kellys, and royals is troublesome. That said a DC UB works well as illustrated below. With regards to vibrancy you just might find,after some practice that you can actually achieve brighter and more vivid prints
The CEO22 graphic is a purple shirt with a DCUB
Seacoast Church straight PC DC
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Medkicking in thank God. OK......yes purple shirt is a bad start. The blue dye #2 used to make most purples, kellys, and royals is troublesome. That said a DC UB works well as illustrated below. With regards to vibrancy you just might find,after some practice that you can actually achieve brighter and more vivid prints
The CEO22 graphic is a purple shirt with a DCUB
Seacoast Church straight PC DC
Tony someday there will be a knock at your shop, it will be my whole shop, we will be there to hang out with you and learn from you. We will bring Pizza, Donuts, Ice Cream, and beer. I hope you except the offering.
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No problem man it just might have to be a Saturday! Meant to come by and see you and Shelly when I was in Nashville but I had to get a move on.
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So if I'm butting up a white and teal, what concern should I have with the two discharge colors mixing and creating a transitional third color where they meet? Flash in between like with a plastisol or will it make no difference?
While the rest of the clowns in New Orleans are getting drenched at the parades, we're printing - attempting to do our first real job of discharge on a 600 piece purple shirt job. Who's dumb and who's dumber in this scenario...hmm....
And Tony, New Orleans isn't that far from Nashville :-).
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Well it looks like we may have a winner for the teal...not nearly as confident about getting a good white. As you can see our initial D-White test (180S) is not near as vibrant as the d-base with a plastisol or WB highlight. We will try the D-white through a 150S because it is close to pleasing given it is a purple shirt. Soft hand and breathability is a plus because these shirts will be worn by people walking the streets of New Orleans for a few hours.
Any suggestions for getting a better white. The square test was a 180S print print with straight D-White with 6% activator. We have screens ready to print a WB highlight if needed but I'd like to try all options first.
Tony...any chance that article for April will make it to print a couple months early ;)
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Actually I'm in Charleston these days. Here's one of the previously unrealized benefits of the DC UB. You steam of the UB jst a titch. Don't try to completely discharge it on the press. The but registered colors print pretty much like they would on a white shirt with no bleeding and no additional flashes required. The CEO22 shirt just has one quick flash (therefore it runs faster..woops another benefit). Heres an example of the reverse. We purposely over print colors to create secondary colors. There are no green, orange, purple inks/ screens, films on this print (woops again saved a bunch more money)
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I mentioned last week that Rutland came by to do some testing and we found their DC white out performed the Sericol and CCI. It is slightly bluer which gives it a more optical white appearance. (An old trick they probably borrowed from their plastisol formulas). They are working on a new one.
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Good to know about the Rutland, will give it a go once we finish our D-White. Well I wish I had great news for our first discharge run (and a fairly long run at 600+) but I knew better than that!
Started of great with the white and teal coming out better than I was expecting on a purple shirt...then the screen failure started. Here is what I think happened and if you have any suggestions I am all ears:
1) First set of screens were underexposed (still figuring out the WR-25) with hardener that was most likely not allowed to dry all the way. Taped some pinholes on the print side of the screen and after about 200 shirts started getting a white line (after running through the dryer) wherever the edges of the tape were on the teal screen. This really had us baffled since it was showing white on the teal screen. My best guess is that either the hardener or ink was causing the tape to breakdown and cause this (White #500 from JandJ) or the discharge base was seeping to the edge of the tape (not sure why the base but not the pigment would seep).
The emulsion became real gummy and the tape would not adhere well and would slide around fairly easily so we bumped up our ltu for round two.
2) On the second set of screens did not want to wait for hardener to dry and thought the underexposure was the main culprit (mistake) and pinholes started appearing after roughly 100 shirts. Possibly still and undexposure problem though there was no gumminess during washout.
What kind of runs are you guys getting with WR-25 with and without hardener. This will help me know if undexposure is the likely culprit. It is just hard to go from 13 ltu with Chromablue to 110 ltu with the WR-25 and have the screens break down so quickly but if I must wait longer for proper exposure than so be it.
I appreciate the help...now its time to order way too many replacement shirts!!!
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Hey Guys,
Are you using reg marks and just taping over them? Uh oh if so. If/when we use reg marks with water base before they hit press we apply block out over them, allow to dry, then apply hardener for jobs over a couple hundred or color changes just to be cautious. We also use a different emulsion but I'm sure the one you have is fine. But the water base will go through the reg marks and around the tape if not
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Under expose on press can be fixed with exposing your screen after the stencil is washed out. Taping is important. I have got the tape lines on my first run of shirts. You have to keep the ink from working it way under the tape. I tape my reg marks and then add rows of take like shingles on a roof so the print stroke starts on tape. If the squeegee runs over tape it will work ink under it after about 50 shirts. No matter what tape you use.
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Hey Guys,
Are you using reg marks and just taping over them? Uh oh if so. If/when we use reg marks with water base before they hit press we apply block out over them, allow to dry, then apply hardener for jobs over a couple hundred or color changes just to be cautious. We also use a different emulsion but I'm sure the one you have is fine. But the water base will go through the reg marks and around the tape if not
What block out are you using? I have only seen waterbase block outs.
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Thanks for the suggestions, will heed the advice. We did post expose the screens for the same time we exposed them so I would love to hear how many prints WR-25 users get with discharge/WB without hardener to give us some sort of benchmark
I will get some fast drying nail polish to use as blockout instead of taping the reg marks on the print side of the screen as I remember reading that in another post. Looking forward to solving these initial hiccups as I can already see why you guys printing discharge and waterbase on a regular basis seem to prefer it to plastisol. It prints faster, easier, and is cheaper to boot...unless of course you screw up a bunch of shirts!
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Hey Guys,
Are you using reg marks and just taping over them? Uh oh if so. If/when we use reg marks with water base before they hit press we apply block out over them, allow to dry, then apply hardener for jobs over a couple hundred or color changes just to be cautious. We also use a different emulsion but I'm sure the one you have is fine. But the water base will go through the reg marks and around the tape if not
What block out are you using? I have only seen waterbase block outs.
On the block out / tape up screen station we have a super small container of our emulsion that we apply with a plastic card. So once the screen is completely dry we cover any reg marks if needed for water base. Wait to dry. Then apply hardener if needed as well. Once completely dry again apply tape. Been doing it for years. No problems.
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No tape on bottom of WB screens ever.
We put reg marks far enough above and below the art to be able to shorten the stroke
and not print them. We also tape over them on the ink side just in case (ink starts flingin)
We use Aquasol HV which as a photopolymer technically shouldn't be as durable, but we don't
use hardener on anything less than 100 pieces or so, and never have any problems. Hardener
on 10K+ plus pieces and no problems either.
Best advice, two things actually, don't rush the pre-press. Take your time exposing and drying and
blocking out etc.
Second, hard sharp squeegees and lots of pressure are pretty rough on your emulsion.
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Yeah, we use Aquasol HV as well. Come to think of it in regards to our water base jobs I just realized I don't know why we have been using tape on that side of the screen. We have everything blocked out if there are reg marks and good to go. Just a hold over from plastisol. Damn, years of tape wasted. Ugh!!!
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Good call on the stiff squeegees as it didn't even cross my mind (though it should have). Need to get some new ones as our current inventory was purchased when we discharge was not even on the radar.
Would a 2/1 coat offer any advantage over a 1/1? I wonder with proper pre-press if there is anything to be gained by a slightly thicker stencil.
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This is Brian -
I'm not sold on the wr25 since there's supposedly a w14(?) that's supposed to have all of the Benefits of wr25 but a much shorter exposure time. Any testers got pro and con feedback? We may give the aquisol a go.
So for pressure and squeegee what are you guys using - 60 duros? 40psi? We were at 45-48 psi with 75/95/75s change the blade and/or less pressure? We kept hearing smash that ink in for good saturation so smash it we did - with plastisols we are anywhere between 15psi-35 psi.
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Under expose on press can be fixed with exposing your screen after the stencil is washed out. Taping is important. I have got the tape lines on my first run of shirts. You have to keep the ink from working it way under the tape. I tape my reg marks and then add rows of take like shingles on a roof so the print stroke starts on tape. If the squeegee runs over tape it will work ink under it after about 50 shirts. No matter what tape you use.
Jon I have to disagree. I have been told by both Kiwo and Murikami this is not the case. If you do not nail the exposure the first time your in for problems. I would have to agree with them. We were under exposing and post exposing with nothing but problems. Once I nailed the exposure there was no need to post expose again. On long runs we use diazzo and hardener. Screens hold up for as long as we run now.
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We only post expose because we are blocking out with emulsion and want to harden that.
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Under expose on press can be fixed with exposing your screen after the stencil is washed out. Taping is important. I have got the tape lines on my first run of shirts. You have to keep the ink from working it way under the tape. I tape my reg marks and then add rows of take like shingles on a roof so the print stroke starts on tape. If the squeegee runs over tape it will work ink under it after about 50 shirts. No matter what tape you use.
Jon I have to disagree. I have been told by both Kiwo and Murikami this is not the case. If you do not nail the exposure the first time your in for problems. I would have to agree with them. We were under exposing and post exposing with nothing but problems. Once I nailed the exposure there was no need to post expose again. On long runs we use diazzo and hardener. Screens hold up for as long as we run now.
So your saying the post exposure does not harden the emulation as well as the first exposure. I could agree with that only because of one reason. If you under expose the first time you would wash off emulsion that was needed, like pin holes, and emulsion thickness, then the pose exposure can't help. But for break down of the emulation on press should be able to be fixed wth post exposure. I do agree a good exposure is key.
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That's a bummer w. the screen breakdown. Print looks good though.
70 or 60/90/60 to prevent the blade contributing to breakdown. You'll get a deeper bend, creating a sort of ink tunnel that will help drive the wb into the fabric. Couple of things you can do:
- Round the squeegee corners.
- Apply emulsion after exposure to beef up the squeegee edges and the start/stop for the blades.
And of course, full exposures. In the middle of 800pcs right now and not expecting a breakdown. Aquasol HV + Murakami hardener MS but any good emulsion suitable for wb will get you there.
I use emulsion to blockout any reg marks, fisheyes, pin holes, etc. so that's reason 1 to post expose but I still think it doesn't hurt to hit your long run screens with 2-3x the original expo time on the squeegee side. I won't hear an argument that this does nothing. Back in the early days I would develop sometimes underexposed screens (using sunlight) gently dry and post expose from the squeegee side and it worked with diazo emulsions so it definitely is doing something to those pure photopolymers which are noted for being able to further cross link in post exposure. Not a substitute for complete exposure though.
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That's a bummer w. the screen breakdown. Print looks good though.
70 or 60/90/60 to prevent the blade contributing to breakdown. You'll get a deeper bend, creating a sort of ink tunnel that will help drive the wb into the fabric. Couple of things you can do:
- Round the squeegee corners.
- Apply emulsion after exposure to beef up the squeegee edges and the start/stop for the blades.
And of course, full exposures. In the middle of 800pcs right now and not expecting a breakdown. Aquasol HV + Murakami hardener MS but any good emulsion suitable for wb will get you there.
I use emulsion to blockout any reg marks, fisheyes, pin holes, etc. so that's reason 1 to post expose but I still think it doesn't hurt to hit your long run screens with 2-3x the original expo time on the squeegee side. I won't hear an argument that this does nothing. Back in the early days I would develop sometimes underexposed screens (using sunlight) gently dry and post expose from the squeegee side and it worked with diazo emulsions so it definitely is doing something to those pure photopolymers which are noted for being able to further cross link in post exposure. Not a substitute for complete exposure though.
Thanks for the great tips:
1. New Squeegees will be ordered most likely tomorrow and we have two 65/95/65 that we will use for this job though I may have a 70 or two lying around.
2. Will increase our exposure a good bit since diazos typically have such a wide latitude to achieve decent exposure
3. When you beef up edges and squeege start and stop points do you do it on squeege side?
4. When I post exposed I had print side facing the light source so it would make sense to flip this over so that the squeegee side gets a chance for some direct light.
5. Going to try some Aquasol HV since so many people speak highly of it. Would CCI's Harden X work with the Aquasol HV?
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By the time the PW article comes out you will all know most of this (BTW it will be a two part, first install covers much of history, sorry) The tape leak is classic failure of underexposure and lack of post exposure possibly combined with improper emulsion/coating technique etc. What makes it more frustrating is that the pigment rarely leaks through; making it difficult to identify the suspect screen.
One of the most commomn errors here is the printer/screenmaker is so scared silly (or misinformed) about leaks that the seemingly obvious solution is to tape the screen silly. The reverse is actually more factual. The emulsion (irregardless of brand/technique) needs to "breathe" or perhaps evaporate ever so slightly. Tape obviously inhibits this; and eventually just a immensly slight bit of activated water will seep through and cause the dreaded tape line; often which is not visible until the garments exit the dryer. We harden screens after 144 pcs. Not usually necesssary but I like insurance especially when it doesn't cost much. More later.