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screen printing => Equipment => Topic started by: ericheartsu on August 08, 2014, 02:25:22 PM
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So we bought and ordered an STE II. It arrived on Tuseday, and our tech showed up for install on Wed.
Tech spent all day Wed. Installing the machine. Thursday morning we started with the training. If you know how to use a computer and printer, then you know how to use this machine. Simple as that.
Our Tech, flew in from South Carolina. His name was Lester, and he was awesome. Made learning about the software and the machine a breeze. We were making screens within 10 minutes of him showing us how the rip worked.
We run all of our screens with Xenon Nova (a diazo emulsion), with a 1/1 sharp side. So far we've made about 40 screens. on our non halftone screens, we are exposing them at about 23 seconds. With our halftone screens we just dialed it in, at 12 secs.
We are running our first discharge job with a screen exposed this way later today, as well as a previously printed 8 color sim process job. So i'm super excited to see what the results are!
I'll update more after we do some printing, but right now we have to print 2000 shirts with an 8 color front, and 1 color discharge back by 6pm!
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Hell yeah Eric! Very jealous, that unit sounds fantastic.
Watch out for big changes in dot gain from your previous sim pro run using film and the one on the STE II, I'm guessing the DTS printer and process will have far less gain.
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It's a game changer. Happy for you
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So we bought and ordered an STE II. It arrived on Tuseday, and our tech showed up for install on Wed.
Tech spent all day Wed. Installing the machine. Thursday morning we started with the training. If you know how to use a computer and printer, then you know how to use this machine. Simple as that.
Our Tech, flew in from South Carolina. His name was Lester, and he was awesome. Made learning about the software and the machine a breeze. We were making screens within 10 minutes of him showing us how the rip worked.
We run all of our screens with Xenon Nova (a diazo emulsion), with a 1/1 sharp side. So far we've made about 40 screens. on our non halftone screens, we are exposing them at about 23 seconds. With our halftone screens we just dialed it in, at 12 secs.
We are running our first discharge job with a screen exposed this way later today, as well as a previously printed 8 color sim process job. So i'm super excited to see what the results are!
I'll update more after we do some printing, but right now we have to print 2000 shirts with an 8 color front, and 1 color discharge back by 6pm!
Glad to hear all is well!
Thanks for the kind words about Lester, I will be sure to pass them on to him.
Let us know if you need anything else.
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So we bought and ordered an STE II. It arrived on Tuseday, and our tech showed up for install on Wed.
Tech spent all day Wed. Installing the machine. Thursday morning we started with the training. If you know how to use a computer and printer, then you know how to use this machine. Simple as that.
Our Tech, flew in from South Carolina. His name was Lester, and he was awesome. Made learning about the software and the machine a breeze. We were making screens within 10 minutes of him showing us how the rip worked.
We run all of our screens with Xenon Nova (a diazo emulsion), with a 1/1 sharp side. So far we've made about 40 screens. on our non halftone screens, we are exposing them at about 23 seconds. With our halftone screens we just dialed it in, at 12 secs.
We are running our first discharge job with a screen exposed this way later today, as well as a previously printed 8 color sim process job. So i'm super excited to see what the results are!
I'll update more after we do some printing, but right now we have to print 2000 shirts with an 8 color front, and 1 color discharge back by 6pm!
Why are your halftone screens different from the spots?
Pierre
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So we bought and ordered an STE II. It arrived on Tuseday, and our tech showed up for install on Wed.
Tech spent all day Wed. Installing the machine. Thursday morning we started with the training. If you know how to use a computer and printer, then you know how to use this machine. Simple as that.
Our Tech, flew in from South Carolina. His name was Lester, and he was awesome. Made learning about the software and the machine a breeze. We were making screens within 10 minutes of him showing us how the rip worked.
We run all of our screens with Xenon Nova (a diazo emulsion), with a 1/1 sharp side. So far we've made about 40 screens. on our non halftone screens, we are exposing them at about 23 seconds. With our halftone screens we just dialed it in, at 12 secs.
We are running our first discharge job with a screen exposed this way later today, as well as a previously printed 8 color sim process job. So i'm super excited to see what the results are!
I'll update more after we do some printing, but right now we have to print 2000 shirts with an 8 color front, and 1 color discharge back by 6pm!
Why are your halftone screens different from the spots?
Pierre
I'm hoping that they're different meshes
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Typically our halftone screens are on either 230, 272s or 305s. But to be honest, with this emulsion we are using, we've always been kind of baffled as to why halftone exposure is usually about half of what a standard blockier image is.
Even when we were using films and our richmond 7k, we'd expose our halftones at 40 units, and solid, blockier images at 70 or 80 units, depending on what the purpose of the screen was.
We did our first run of shirts on Friday with screens made through this bad boy. We did a run of roughly 800 shirts. 8 color sim process front (one color was a discharge color, the word "passanger"), and a one color discharge back print.
The front print registered super easy (we did not use a tri lock, as it's on a non compatible press), and we had ZERO issues with pinholes, or the screen breaking down with the discharge print.
The back print, registered very easy, (used a different press, but did not use the trilock), and was a one color discharge print. The only issues we had was a slight screen breakdown, but this print was printing about 1/2 an inch below the collar. The breakdown could have been avoided with proper screen taping, but we were in a rush to get this job out.
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Typically our halftone screens are on either 230, 272s or 305s. But to be honest, with this emulsion we are using, we've always been kind of baffled as to why halftone exposure is usually about half of what a standard blockier image is.
Even when we were using films and our richmond 7k, we'd expose our halftones at 40 units, and solid, blockier images at 70 or 80 units, depending on what the purpose of the screen was.
How are you determining what is the correct exposure? Do dot areas fill in or bold areas wash out when the same exposure is used on the same mesh counts with these two different types of images?
It shouldn't be the case. Though I'll confess that I do very little high end type work, I was always taught that an exposre time (or units) is determined by the emulsion deposit and not by the image itself.
The emulsion, of a given thickness, is either cross-linked or not, and shouldn't "know" if there is detail or not.
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I wish I knew the technical aspects more. We quote ALL screens the same, except for our low meshes.
But it would be great if anyone could chime in and teach this youngin a lesson
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I wish I knew the technical aspects more. We quote ALL screens the same, except for our low meshes.
But it would be great if anyone could chime in and teach this youngin a lesson
get an exposure calculator from Nazdar and expose your screens. You should have the step #7 be the same color as the rest of the exposed emulsion (there should be no difference between the first seven steps, the first visible one should be the 8).
pierre
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If you can figure out how to do an exposure calculator on a screen made with the wet ink out of the i image ste let me know...... Doing the "step wedge" for the dts screens isn't really something I've figured out how to do well yet. Using film, etc no problem but the times are vastly different then the ink sitting on screen.
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i was just thinking of that danny!
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If you can figure out how to do an exposure calculator on a screen made with the wet ink out of the i image ste let me know...... Doing the "step wedge" for the dts screens isn't really something I've figured out how to do well yet. Using film, etc no problem but the times are vastly different then the ink sitting on screen.
I am talking about the 21 step scale. It is a small piece of film you stick on the part without the print. Since it is so thin, it should be fine with your sensor on the STE.
pierre
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http://www.stouffer.net/TransPage.htm (http://www.stouffer.net/TransPage.htm)
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but you're still shooting through something that will block some UV light, or are those made to not block any UV
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but you're still shooting through something that will block some UV light, or are those made to not block any UV
That's what I'm saying...... If I take a piece of clear film and lay over the printed ink from dts it slows it down minimum 30% but that number varies depending on mesh count.
I guess I'm just not understanding what Pierre is saying LOL...... I need to put the visual with it in order to understand LOL
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but you're still shooting through something that will block some UV light, or are those made to not block any UV
That's what I'm saying...... If I take a piece of clear film and lay over the printed ink from dts it slows it down minimum 30% but that number varies depending on mesh count.
I guess I'm just not understanding what Pierre is saying LOL...... I need to put the visual with it in order to understand LOL
film Dmin is not relevant here, the actual density of the step 7 is. So even though it's on the film, you should get the right readings.
pierre
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The maker of our DTS supplies a digital file for exposure calculations. Maybe if one could get a really good scan of the 21 step calculator they could output it to screen...just a thought.
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You sure Pierre? Is that a straight nd piece? Should I be putting that strip under a clear part of my film to compensate for the dmin of my film?
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You sure Pierre? Is that a straight nd piece? Should I be putting that strip under a clear part of my film to compensate for the dmin of my film?
I was taught to put the strip under my film .. I wonder if I've been doing it wrong all along?
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sorry not 100% sure of anything, but that is what I understand.
The film or no film, even on WP milky stuff, is so insignificant it should not make any difference. On a good film the difference is around 5% which is 6 seconds on a 2 min exposure. If you are within 5% of the full exposure time, you are better than 90% of the shops. We spent a significant amount of time and money on testing our screens and all said and done, we were underexposing by about 25%. The kicker is, our exposure times were 2-3 times LONGER than anybody else with similar emulsion and coating!!!
The moral of the story is, get the Stoffer strip and measure your exposure times!
pierre
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Oh, I have one... it's TAPED to the exposure unit glass so it's NEVER left off of an exposure.
I just want to make sure we are using it right.
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I'm not sure if this is 100% accurate but maybe to clarify:
The Stouffer 21 step greyscale strip is there to measure the quality/thoroughness of your exposure, not your resolution or imaging.
When calibrating for an emulsion we use a combo of the Stouffer strip as well as strips of test films- with halftones at various LPI as well as stochastic at common ppi and line segments at various points -outputted from your regular device.
*CTS users may need to run the same screen through the unit multiple times, allowing to dry after each pass to get the various LPI outputs, etc.....presuming that is an option, or you may need to simply run through more screens.
To save screens on the calibration grid out the screen with a sharpie and, taking a best guess based off emulsion mfg tech sheets or experience, jot down a variety of LTU on each square. Place the Stouffer along with the test films in one square at a time. Cover the other squares with rubylith or anything that's 100% uv opaque. Expose each square at the LTU written on it.
Check your results. Look for the correct hardness (step 7 intact) on the Stouffer and then, if there is a range of cells with the 7 intact, choose your optimal resolution. Optimal resolution is going to be subjective based on what LPI or PPI stochastic or line point you commonly run on this mesh/emulsion/coating combination and what % range you need to hold in the case of LPI. If you are long run discharge and waterbase all day long in your shop you may want to sacrifice the range for a somewhat over exposed stencil or even setup a spot color exposure value v. halftone/stochastic/fine line.
It's a bit of work compared to step wedges, winging it, etc. but it yields data that tells you what you can and cannot hold on a correctly exposed screen.
Now, this business with the film is a little tricky because the Stouffer strip is obviously imaged film. Your film may or may not be at the same dmin and dmax. If you use CTS you have no film. Pierre's suggestion to just put the strip on probably makes the most sense as the Stouffer strip, in my humble opinion, gives you a range of quality of your exposure, not an exact figure. Resolving techniques are too varied (unless your using one of those sweet M&R washout systems) to expect to get perfect results and you'll find step 7 flapping around or sort of hanging on in some cases, rock solid in others. You just want to be in that step 7 intact ballpark. From there it's all about optimal resolution from your image setting device to the screen and, just as importantly, knowing what you can and cannot hold on various mesh counts/coats/emulsion types.
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Awesome input and technique Chris!
Only thing I have to add... Picking nits here... dMax isn't an issue with that strip because its an engineered neutral density filter... So it's opaqueness is based on X light passing through that step... Now YOUR dMax makes that step kind of relative as 7 being perfect is ok if your dMax is "good enough"... If it's passing light through it then you are exposing underneath your stencil to a degree.... Now you have a balancing act.
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Great point!
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I got this to start testing screens to get accurate times for my starlight (not DTS) since I really didn't have the slightest idea what to start at other than guess (way over) on my first couple screens.
http://www.kiwo.com/Product%20pages/Exposure%20films.html (http://www.kiwo.com/Product%20pages/Exposure%20films.html)
The gist is you get 3 films, 1 for coarse screens, 1 for medium screens and 1 for fine screens. You put the film on the screen, then you cover it with a density sheet that is a lot like that 21 step test in that it covers each section on the film with a slightly darker segment.
You expose for double what you think it should be and then whatever section you can still hold detail on after washout is your factor.
For example, I tested a 110 screen at 15 seconds and was able to hold everything in the x0.5 column and up. 0.4, 0.3, etc washed out. So now I know on 110 screens that I coat the same as my test I only need to go 15 seconds x .5 or 7.5 seconds (I'll call it 8 seconds)
I'm attaching a couple images. Just quick cell phone captures...the one you can see where in the lower right box of 0.4 I started losing dots, I could hold them on 0.5
The other shows the film with the density film on top
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I got this to start testing screens to get accurate times for my starlight (not DTS) since I really didn't have the slightest idea what to start at other than guess (way over) on my first couple screens.
[url]http://www.kiwo.com/Product%20pages/Exposure%20films.html[/url] ([url]http://www.kiwo.com/Product%20pages/Exposure%20films.html[/url])
The gist is you get 3 films, 1 for coarse screens, 1 for medium screens and 1 for fine screens. You put the film on the screen, then you cover it with a density sheet that is a lot like that 21 step test in that it covers each section on the film with a slightly darker segment.
You expose for double what you think it should be and then whatever section you can still hold detail on after washout is your factor.
For example, I tested a 110 screen at 15 seconds and was able to hold everything in the x0.5 column and up. 0.4, 0.3, etc washed out. So now I know on 110 screens that I coat the same as my test I only need to go 15 seconds x .5 or 7.5 seconds (I'll call it 8 seconds)
I'm attaching a couple images. Just quick cell phone captures...the one you can see where in the lower right box of 0.4 I started losing dots, I could hold them on 0.5
The other shows the film with the density film on top
this is sort of what we did and were as a consequence using wrong exposure times for years. While similar, it does not have the step specified at which the exposure is correct (or so it seems as I read it). It looks like it is just finding the time that holds the best detail, rather than the time it takes to properly expose the screen. Or am I reading it wrong?
pierre
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this is sort of what we did and were as a consequence using wrong exposure times for years. While similar, it does not have the step specified at which the exposure is correct (or so it seems as I read it). It looks like it is just finding the time that holds the best detail, rather than the time it takes to properly expose the screen. Or am I reading it wrong?
pierre
You mean like the solid step 7 on the Stouffer strip? It does have that too, the part at the very bottom where the arrows are facing each other. In between the areas you look for your area that has no change. It's hard to tell because of the camera flash.
Brandon
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this is sort of what we did and were as a consequence using wrong exposure times for years. While similar, it does not have the step specified at which the exposure is correct (or so it seems as I read it). It looks like it is just finding the time that holds the best detail, rather than the time it takes to properly expose the screen. Or am I reading it wrong?
pierre
You mean like the solid step 7 on the Stouffer strip? It does have that too, the part at the very bottom where the arrows are facing each other. In between the areas you look for your area that has no change. It's hard to tell because of the camera flash.
Brandon
COOL! I missed that part. It makes a lot of sense and I'll probably pick one up as it just looks like a good tool to have.
They do point out the difference between the optimal exposure and optimal resolution: "It is possible that the optimum curing time and the optimum resolution exposure time differ slightly. For the final determination of the production exposure time, the requirements of the artwork should be the deciding factor, because: optimum curing = high resistance to long print runs, optimum resolution = finest detail quality."
This is a good point to bring up and gets me thinking about what we are doing. . .
pierre
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this is sort of what we did and were as a consequence using wrong exposure times for years. While similar, it does not have the step specified at which the exposure is correct (or so it seems as I read it). It looks like it is just finding the time that holds the best detail, rather than the time it takes to properly expose the screen. Or am I reading it wrong?
pierre
You mean like the solid step 7 on the Stouffer strip? It does have that too, the part at the very bottom where the arrows are facing each other. In between the areas you look for your area that has no change. It's hard to tell because of the camera flash.
Brandon
COOL! I missed that part. It makes a lot of sense and I'll probably pick one up as it just looks like a good tool to have.
They do point out the difference between the optimal exposure and optimal resolution: "It is possible that the optimum curing time and the optimum resolution exposure time differ slightly. For the final determination of the production exposure time, the requirements of the artwork should be the deciding factor, because: optimum curing = high resistance to long print runs, optimum resolution = finest detail quality."
This is a good point to bring up and gets me thinking about what we are doing. . .
pierre
Yeah, I noticed it is slightly different. I print for myself so I never do long runs. However, I think if I were going to I would probably go for detail and then post expose if needed.
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Exposure and resolution of fine art images goes beyond the exposing process with light. D max of ink jet film gets iffy below 10% tonal values, same for CTS Ink Jets. The hardness scale helps with making sure the screen receives a certain quantity of light, but the effect of real film d-max vs ink jet d-max is dramatic in halftone formation at the same hardness value. Solid areas and mid to upper tonal values of ink jet are similar to real film. In CTS systems wax vs inkjet is similar to real film vs ink jet in opacity. Nothing wrong at all with CTS systems or Ink Jet, you can slightly under expose and capture lower tonal values, but what happens to the printability of the dot in underexposure? The side walls get affected. Wider openings on the squeegee side are typical with underexposure and the result is dot gain. The sharpness of the dot also gets affected and in upper 1/4 tone values underexposure can effect halftone reproduction and cause 85%+ dots to disappear due to angled side walls. Printing is subjective. We can all make decent prints, but at some point there are companies who master the printed dot better due to better films, exposure units, dialing in proper exposure time, and in choice of emulsions, or adding a face coat to get a sharper emulsion shoulder to prevent dot gain. Achieving 1:1 reproduction of the tonal art at full exposure is a sign of a good emulsion. Note, 'full exposure'. If you have to underexpose emulsion to image the dot it could be part of the emulsion's properties, your light source, your EOM. Sure I sell Murakami, and for a very good reason, my best prints came from Murakami Aquasol TS, which has been taken over by Aquasol HVP in sales due to shops wanting more viscosity, but TS will make better tones and have excellent emulsion strength. A hard 7 on emulsion A at full exposure may have difficulty with dots below 10% and need underexposure at a lower hardness. A hard 7 on Emulsion B (TS or HVP) will image 2-10% tonals better with full exposure. In today's print market of waterbase, discharge, and HSA inks this full exposure is crucial to get a screen that holds a good tonal ramp capture and more importantly, stands up to these harsher inks. 1:1 screen imagery at full exposure equals good production yields with less downtime and less headaches with breakdown. Full Exposure of high quality emulsions allows higher line counts to image 65-85 lines in plastisol or index printing that makes an image glow with smooth tonals and sharper imagery. Taken a step further, hybrid screens of 65lpi with stochaistic in the 10-4% dot yields even finer tonal rerproduction that avoids vignette moire which can be imaged with a RIP like Wasatch.
The hardness scale serves another important function. It monitors your lamp strength. If you expose with light units this issue is compensated, but with seconds or timed exposures suddenly your emulsion can't hit a hard 7 and more time has to be added, and then more time, showing the need for a new bulb. Of all the tools for exposing emulsion well, the bulb is often replaced grudgingly to squeeze every penny out of the bulb while downtime on press is blamed on emulsions. Hmmm, maybe swapping it out early and keeping the old one as back up could keep the shop running at full speed. 90% percent of my tech calls get solved with good light. The hardness scale is a great tool to prove your light system is in great shape. Underexposing should never be the first option for tonal capture, your emulsion and quality light are the winning combination for 1:1 image reproduction.