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screen printing => Screen Making => Topic started by: islandtees on May 05, 2012, 06:40:32 PM
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We use Chromablue. When you expose it is very tacky after exposure. The film sticks and many times the black ink comes off and gets ruined. We have done like others with the baby powder. We are in Florida.
The screen room is a seperate room with A/C, dehumidifier, and heat. The screens are checked with a moisture meter. They are dry.
Curious if anyone expierenced this and what did you switch to?
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we have different emulsion, different film (waterproof) and the same problem even in the cold dry winter here in central, coooooold & drrrrrry in NY.
The source is the waterproof coating on the film, the fix is in your powder bottle.
mooseman
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The source is the waterproof coating on the film, the fix is in your powder bottle.
mooseman
Mike,
I had recently switched to CTR and found the same thing happening down here in Houston. Well I guess that gives it away that it's not very dry.
Can you explain the "fix is in your powder bottle"?
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Can you explain the "fix is in your powder bottle"?
Baby powder, Talcum Powder, a light dusting of the screen is the band aid for this problem.
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We have the same problem with Chromablue and Saati PHW Red, AC'd dark room with dehumidifier, 35% humidity or lower. Baby powder is the only remedy besides changing emulsion. The PC-701 I sampled a few weeks ago did not have much post exposure tack, it certainly didn't take the ink off the film positive. I'm trying to remember if Kiwo One Coat did this and I think it did. Pretty much all the higher solids content emulsions/pure photopolymer we've used have been notorious for this problem, except the PC-701. Dual cures don't have this problem at our shop.
This recent talk about emulsion has made me rethink our current emulsion usage and I'm going back to testing out new emulsions. I think we all should do this with ALL of the products we use every year or two. There is always something better around the corner or a product that you've never used that outperforms your current one, but if you're not open minded to trying new products then you'll be left in the dark and wasting time and money. There was a shop in my area that seriously didn't know more than two different ink manufacturers existed. Wilflex and Union were their only choices, and there is no telling what else they didn't know about emulsion and screen chemistry. I know most shops don't use these forums for information and rely on an outside sales rep or maybe the wind to keep them up to date on new products and techniques, and then I guess there are some that could give a damn about that because they finally found something that worked somewhat ok and just stuck with it.
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Where do you baby powder yoru screens? We used to do it, and it made a mess in our dark room.
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Another way to fix it is with a CTS unit.
I have only found this to be an issue if the humidity gets too crazy in the dark room. A light powdering fixes it like others have mentioned.
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We have the same problem with Chromablue and Saati PHW Red, AC'd dark room with dehumidifier, 35% humidity or lower. Baby powder is the only remedy besides changing emulsion. The PC-701 I sampled a few weeks ago did not have much post exposure tack, it certainly didn't take the ink off the film positive. I'm trying to remember if Kiwo One Coat did this and I think it did. Pretty much all the higher solids content emulsions/pure photopolymer we've used have been notorious for this problem, except the PC-701. Dual cures don't have this problem at our shop.
This recent talk about emulsion has made me rethink our current emulsion usage and I'm going back to testing out new emulsions. I think we all should do this with ALL of the products we use every year or two. There is always something better around the corner or a product that you've never used that outperforms your current one, but if you're not open minded to trying new products then you'll be left in the dark and wasting time and money. There was a shop in my area that seriously didn't know more than two different ink manufacturers existed. Wilflex and Union were their only choices, and there is no telling what else they didn't know about emulsion and screen chemistry. I know most shops don't use these forums for information and rely on an outside sales rep or maybe the wind to keep them up to date on new products and techniques, and then I guess there are some that could give a damn about that because they finally found something that worked somewhat ok and just stuck with it.
Aquasol is still my choice for a non tacky emulsion that you can coat until the cows come home.
The Chromablue exposes just as fast as Aquasol, with the tackiness and smelly side effect was my only complaint. Everything else was on par. But I too feel like it's the consistency of really hard taffy when pulled from a dehumidified dark room. Just doesn't feel as dry as it should I guess, but it definitely is dry.
I'm going back to Aquasol for now and will also order a gallon of the Kiwo discharge emulsion from Tubelite. Also, with as many screens as I'm burning these days, it would benefit me to find one that comes in a 5 gallon as well. I just can't fathom how to dispense it into my coater, how in the world do people do that, with a pump?
For the discharge printing, I put the murakami hardener on dry screens and it holds up perfectly for longer water-based runs. Yeah it's one more step, but it's actually easy and only adds a couple minutes. For the piece of mind of not switching emulsions, it's well worth it and predictable.
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Where do you baby powder yoru screens? We used to do it, and it made a mess in our dark room.
we have a cabinet where we keep our exposure ready screens. When we select the screen we simply take it from the cabinet hit it with the powder spread it with our hand and place it directly onto the exposure glass.
We do this in open light , yes fully open light with no filters or other precautions.
mooseman
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I just can't fathom how to dispense it into my coater, how in the world do people do that, with a pump?
Ulano has a pump for 5 gal buckets... Or most people I know just pour into a gallon ;)
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What if you put a spigot on the bottom of the bucket?
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Where do you baby powder yoru screens? We used to do it, and it made a mess in our dark room.
we have a cabinet where we keep our exposure ready screens. When we select the screen we simply take it from the cabinet hit it with the powder spread it with our hand and place it directly onto the exposure glass.
We do this in open light , yes fully open light with no filters or other precautions.
mooseman
Pssst. Next time put the film on it for better results. :D
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I never understood why some shops put their exposure unit in a dark room. I like to see what I am doing. I put mine out in the light with ZERO protection and it works PERFECT!
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Ditto
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I don't even have a darkroom but if I did the exposure unit would not be in it.
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I never understood why some shops put their exposure unit in a dark room. I like to see what I am doing. I put mine out in the light with ZERO protection and it works PERFECT!
So do we, but i just didn't know if it was best to put the powder on first then the films, or vice versa? i'm assuming the previous statement is the correct one.
We do however line up our films in our dark room.
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Only thing I do in the dark room is COAT SCREENS. THATS IT!
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Actually, coating does not demand darkness as when still liguid, the emulsion has extremely reduced photosensitivity. (this is not to say to leave the cover off indefinitely)
Drying and storing the screens is another matter, and larger shops may require a whole room rather than a cabinet.
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When I was dealing with the stickiness I used something similar to a 'pounce bag'. (I know there are at least a few letterheads on here who know what I'm talking about... :) )
Cut a square of T-shirt, throw a handful of talc in it, rubber band it into a little bag--tap it to get some out, nice for spreading it out too.
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Only thing I do in the dark room is COAT SCREENS. THATS IT!
we coat like before in open...we do different things in the dark room : ::)
mooseman
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[quote
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does anyone attach films to the screen? dont know why you would do that.
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Where do you baby powder yoru screens? We used to do it, and it made a mess in our dark room.
we have a cabinet where we keep our exposure ready screens. When we select the screen we simply take it from the cabinet hit it with the powder spread it with our hand and place it directly onto the exposure glass.
We do this in open light , yes fully open light with no filters or other precautions.
mooseman
Pssst. Next time put the film on it for better results. :D
we never attach the films to the screen for placement
actually we have a placement system on our exposure unit so the film is sitting there properly registered to the pallet / screen association just waiting for the powdered screen to hit the glass .
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well, damn, thought i had u.
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well, damn, thought i had u.
:)
mooseman
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I use Imagemate PC701. The only time I have issues with film sticking is when I am in a rush and the screen hasn't totally dried. When the screens are totally dry I just lift a corner of the film after exposire and it peels off. None of the ink has made a mark on the emulsion. Yesterday I had a last minute rush job come in and of course I didn't have any coated screens ready so I had to do a hurry up coating and drying and I ruined the film.
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does anyone attach films to the screen? dont know why you would do that.
We do, as we have an older press, and do not have a registration system for it. We register each film to the screen, and line up the films that way.
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I do also. I have a grid on my tabletop screen board.I place films lining up with marks, and tape attached.
I then place my screens into set stop blocks, and press to stick the film.
I used to punch films and/or carrier sheets to fit on pins, but got away form that when I moved away from camera and rubylith during the vellum era, and never went back.
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here is our system, just a registration sheet that defines the pallet position under the screen, inner edges of MZX frames etc.
The set up assumes our press print head is roughly centered and the frame will join the back clamp normally.
The real value here is when we use multiple images in one screen or on multi color jobs.
On multi color prints we simply add the second color film ovet the film previously locating it to the art registertion marks then pulling the first film.
This insures we never run out of adjustment travel on the press or get a screem that mechanically can't be clamped in without aligning all images.
Here is a pic of the registration / placement sheet on the exposure glass, note that at the top of the picture there are a couple of pins, ( male half of large dress snaps) attached to the glass. Reg sheet has aligning holes in reinforced tabs.
http://i184.photobucket.com/albums/x296/copdaddy/MRS3DSCF3155.jpg (http://i184.photobucket.com/albums/x296/copdaddy/MRS3DSCF3155.jpg)
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humidity is the issue. i put a air conditioner in the srcreen room and poof..no more tackiness
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humidity is the issue. i put a air conditioner in the srcreen room and poof..no more tackiness
I wish that were the fix for us. We've got an AC unit and a dehumidifier and it's just as bad as it was before we had that stuff and the humidity was 70%, now it's around 30%. I've played around with the temperature and gone from about 68 to 85, with all humidity levels in between, nothing changes until the brand/type of emulsion changes.
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we are using murikami photo blue for our plastisol jobs.
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humidity is the issue. i put a air conditioner in the srcreen room and poof..no more tackiness
I wish that were the fix for us. We've got an AC unit and a dehumidifier and it's just as bad as it was before we had that stuff and the humidity was 70%, now it's around 30%. I've played around with the temperature and gone from about 68 to 85, with all humidity levels in between, nothing changes until the brand/type of emulsion changes.
I concur lol
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I've got a gallon of orange coming in today, hopefully within the hour. I've got 5 screens waiting to be coated with it and I might expose them later today if I can.
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Humidity is often the culprit but also know that some emulsion/film combinations are sensitive to heat. I have often seen this in shops where the exposure unit gets to hot due to constant use or cooling fan failure.
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What do you guys think, is there a connection to emulsions that reclaim like bubble gum (as opposed to actually dissolving) and this tackiness?
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What do you guys think, is there a connection to emulsions that reclaim like bubble gum (as opposed to actually dissolving) and this tackiness?
I don't reclaim enough to really know which emulsions reclaim which way, but I would like to know if there is a correlation there.
What emulsions have people had this issue with? For us it was Chromablue, Saati PHW Red and Kiwo One Coat, all PP's and above 45% solids content. What else can we add to this equation and what emulsions? I'm sure we can break this down and get a good feel as to why this happens and where it's going to occur.
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What do you guys think, is there a connection to emulsions that reclaim like bubble gum (as opposed to actually dissolving) and this tackiness?
I have had that issue only with PPs, and when I dont let the screen fully dry.
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I have only used pure photopolymer emulsions for the last eight or so years.
The absolute easiest reclaim has been with Chromaline PL (just dissolved and was never tacky on exposure) and the gummiest and stickiest was Xenon Nova. (Interestingly, the two also represent extreme ends of the price scale as well)
My present CCI Prochem PFX, I'm still getting used to, but seems to be in the middle.
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I've only seen it in the higher solids emulsions.
If I had to guess, the higher solids means quicker drying, or so it would
seem. I'd assume the outside layer dries quickly, leaving moisture sandwiched inside.
Aquasol HV, no problemo.
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Aquasol HV, no problemo.
Another +1 for Aquasol reclaim, no gummy. Just a few minutes in the tank and it washes out clean even on my 2/4 coated 110 screens.
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We use CPtex emulsion, and it tends to stick, especially when the weather changes, thats when we notice it the most.
We reclaim in CCI Gem-zyme wash, and we've had fantastic results, and rarely any gummy mess, even when our films stick to our screens!