# I think it's time for aluminum plattens???



## earwicker7 (Oct 27, 2014)

99% sure I already know the answer to this...

If you look at these pictures, you'll see that there is some serious banding/striping going on. It's especially noticeable on the cat's chin... that's supposed to be a solid color.

I tried all kinds of stuff (spraying screen de-clogger, trying a different squeegee, adjusting the off contact) before I decided to check if the platten was warped, given that I work out of a cold, damp basement. There is definitely some warp in it, even though it's only been in use since the summer.

It's probably time to just bite the bullet and buy aluminum plattens, right?


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## killroy (Feb 16, 2014)

Once you go with aluminum you'll wish you did it sooner. I'd also suggest putting the rubber on top. It will help with prints, but the main thing is flash times go down. The rubber helps deflecting the heat back up.


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## DavidLRobison (Feb 3, 2015)

What your seeing is in the screen most likely, examine your screen carefully, it looks like a "moiré" pattern.
Most often caused by an improperly stretched or coated screen, or a screen not fine enough to hold your halftone count. Since the Halftones don't look like gradients and more like specific % fills Id look at your film vs screen count. I use 55 line round dots at 22degrees on all colors and use a 230 mesh-305 mesh to hold them. Yours look to be about a 45 or 50 line at what appears to be about 45 degree angle. Most screens are stretch with the fabric 90 degrees to and parallel to the frame so your angles will have less likelihood of creating a "Moiré" patter at 22 degrees to the fabric.

good luck.

Oh and the surface of your platen can count for a lot try cleaning it and putting down fresh pallet tape though and that should clear that up without having to chance platens.


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## earwicker7 (Oct 27, 2014)

DavidLRobison said:


> What your seeing is in the screen most likely, examine your screen carefully, it looks like a "moiré" pattern.
> Most often caused by an improperly stretched or coated screen, or a screen not fine enough to hold your halftone count. Since the Halftones don't look like gradients and more like specific % fills Id look at your film vs screen count. I use 55 line round dots at 22degrees on all colors and use a 230 mesh-305 mesh to hold them. Yours look to be about a 45 or 50 line at what appears to be about 45 degree angle. Most screens are stretch with the fabric 90 degrees to and parallel to the frame so your angles will have less likelihood of creating a "Moiré" patter at 22 degrees to the fabric.
> 
> good luck.
> ...


230 Mesh, 46 LPI rounds at 22.5 degrees... do you think that would cause it?


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## earwicker7 (Oct 27, 2014)

One other thing... I thought moire was with more than two colors overlapping? This is spot color with gradients, so it is only black ink.


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## DavidLRobison (Feb 3, 2015)

Yeah it could. Your certainly missing dots in a pattern that fits the description I gave above although your screen mesh and line counts sound fine. Just try returning your screen. Are you using a good dual cure emulsion or a single open and use emulsion? My experience is that dual cure emulsions like DC10 from CCI or TLX from Ulano are really good dual cure emulsions and cheaper than the open and use fast burn stuff.
Our burn times on 230 are around 45 seconds so if your using a 10 second single cure emulsion you have to slow down a bit but the results are much better in the long run.


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## DavidLRobison (Feb 3, 2015)

Moiré can happen on a single color print like your illustrating, its a perfect example because the dots, the screen mesh of the fabric and the unpredictable mesh of the t-shirt weave are all considerations. I'd be willing to bet its the screen though, its not uncommon to have a screen exhibit Moiré if its not stretched properly, coated with enough emulsion to allow for all the dots to hold, or if the shirt itself is swallowing a certain percentage of the dots as they go down.(the last is usually on very fine halftones of 65 line and up)


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## DavidLRobison (Feb 3, 2015)

If you have another screen of the same mesh burn it. If your emulsion is the issue or the mesh stretch is off kilter you will see another pattern but it will appear differently never the same twice. If the pattern is exactly the same as before its the art itself look at the film and verify its actually correct. I'd bet its the screen though, i'm pretty sure of it from what you have shown. I coat my screens with a double sided scoop coater (230 mesh at 280 newtons) using the dual cure emulsion and the sharp side of the coater i begin on the inside of the frame and make two passes fast and even flip repeat on the outside and then flip again and repeat on the inside of the screen. Place it into a drying rack face DOWN so the wet emulsion is captured primarily on the outside of the mesh. This will allow your Halftones in the screen to be clear and crisp and provide a very tine ink well for each dot and your prints will be much cleaner and crisper, accurate and color correct.

Good Luck.


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## earwicker7 (Oct 27, 2014)

DavidLRobison said:


> Yeah it could. Your certainly missing dots in a pattern that fits the description I gave above although your screen mesh and line counts sound fine. Just try returning your screen. Are you using a good dual cure emulsion or a single open and use emulsion? My experience is that dual cure emulsions like DC10 from CCI or TLX from Ulano are really good dual cure emulsions and cheaper than the open and use fast burn stuff.
> Our burn times on 230 are around 45 seconds so if your using a 10 second single cure emulsion you have to slow down a bit but the results are much better in the long run.


I'm using Ryonet Pro-Chem DXP. I just checked the date on it, and it looks like I was a couple of days (literally, two days) past the 3-month mark at which it's supposed to be tossed.


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## earwicker7 (Oct 27, 2014)

DavidLRobison said:


> If you have another screen of the same mesh burn it. If your emulsion is the issue or the mesh stretch is off kilter you will see another pattern but it will appear differently never the same twice. If the pattern is exactly the same as before its the art itself look at the film and verify its actually correct. I'd bet its the screen though, i'm pretty sure of it from what you have shown. I coat my screens with a double sided scoop coater (230 mesh at 280 newtons) using the dual cure emulsion and the sharp side of the coater i begin on the inside of the frame and make two passes fast and even flip repeat on the outside and then flip again and repeat on the inside of the screen. Place it into a drying rack face DOWN so the wet emulsion is captured primarily on the outside of the mesh. This will allow your Halftones in the screen to be clear and crisp and provide a very tine ink well for each dot and your prints will be much cleaner and crisper, accurate and color correct.
> 
> Good Luck.


So, if I understand you correctly, you're doing a total of four passes on the ink side, and two on the print side? I've been doing two and two, but not with the sharp edge.


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## DavidLRobison (Feb 3, 2015)

Yes but don't do that much if your using a high solid single cure emulsion. The dual cure emulsions don't have as much photosensitive solids so they require a little more care. But Yes 2-inside,2-outside, 2-inside sharp side only.


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## earwicker7 (Oct 27, 2014)

I've been doing some research on the half-tone angle issue. I'm wondering... since you're working with mesh stretched at either 90 or 180 degrees, what happens if you don't line up your film at a perfect right angle to the base of the screen? I'm using one of those Ryonet pre-registration templates, and when I lay down the screen, I try to make sure all four corners fit as well as they can, and I have a feeling this may result in the mesh being at, say, an 88 or 92 angle, relative to the image on the film. Should I instead be shooting for just one of the sides matching up perfectly? That would seem to be a better way to get the 90 or 180 degree thing nailed.


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## sben763 (May 17, 2009)

Moiré pattern - Wikipedia, the free encyclopedia Explaination of Moiré. All prints can contain moiré and basically do. What you want to avoid is undisirable moiré. 

The moiré can happen with just 1 color. This is due to the interfacing with the mesh. When printing single color it's common to use 22.5. Honestly it really doesn't matter if it's off a degree or 2. In my experience avoiding angles 0,45,90 and any multiples of each as the become repeating angles IE 90 and 180 are the same. 45 is used but I have seen issues with diamond patterns. 

When printing multi color there are many ways to print angles. Flamenco, as David suggested is all colors at the same angle. The issues with this type of printing is its dot on top of dot, it does reduce the probability of undesired moiré but also suffers from color. Rosette which in itself is a moiré pattern. This uses off set angles for each color and creates a circle of dots. It is more prone to undisirable moiré but has a wider color gamut. There is a newer style interlocking halftones. I have been experimenting with this for almost 3 years and IMO is the best method. 

The thinking of the LPI IMO is out dated. The thinking of mesh divided by 4.5 to obtain the LPI was Delores years ago. Today's emulsions and mesh are so much better you can push that envelope as long as your coating techniques and exposure times are good . I have been exposing 55 LPI on 166 mesh with great results. Down to about 5% you can maintain 100% of the dots. Below that you will start loosing dots as there will be no threads to hold some of the smaller dots. You will maintain some of them as not all of them fall where there in no threads. 

I know there will be other that disagree and everyone is entitled to their opinions. But that what they are until they have tried and done all the testing I have.


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## DavidLRobison (Feb 3, 2015)

What he says above is true to a degree. I've been using same angle same patterns for a long time now. Rosette patterns are great for substrights with little or no aborbency with white backgrounds or base prints not very suitable for shirts. Everyone is entitled to their own opinion for sure, but the result I get from what I do is very good. here is a bad picture of one of my self promotional shirts and you can see flesh tones are great, subtle shades are excellent and detail is awesome.
Sorry for the lousy picture, i used a phone camera.


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## DavidLRobison (Feb 3, 2015)

If you lay the shirt down next to the color comp they are incredibly close, the crappy photo doesn't do it justice but i hope you get my point.


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## sben763 (May 17, 2009)

DavidLRobison said:


> If you lay the shirt down next to the color comp they are incredibly close, the crappy photo doesn't do it justice but i hope you get my point.


Have you ever had experimentation with high LPI on low mesh? Interlocking halftones. 

I don't post to start term oil, I post legit info to show differences. Starting out all the "industry standards" and what I consider bad info put out there by a lot of suppliers can hold newbies back. All of the info I post is from personal experiance and testing the limits. 

Here is a screen that I exposed this year. It's a 128 at 55LPI. And yes before anyone says its contains moiré, it does to a point but the camera makes it look worse then it is and this was a interlocking print so the little that is actually contains was suppose to be there as texture. What I was surprised about this screen is that there seems do be nothing lost. I didn't take the time to do a comparison as it was my busy time. I mainly print April though November, do some printing in the winter but I do enough in my busy season to cover the entire year.


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## sben763 (May 17, 2009)

The print. Not my artwork. This was supplies at 196 DPI. 

Sorry for the multiple post but for whatever reason you upload multiple pics from iPad. It will only upload the last chosen.


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## earwicker7 (Oct 27, 2014)

After doing some experimentation, it does seem like one of the screens moires much worse than the others. Should I just toss this one out? It's a 230, so I can't honestly see doing anything other than halftones on it.


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## TYGERON (Apr 26, 2009)

earwicker7 said:


> After doing some experimentation, it does seem like one of the screens moires much worse than the others. Should I just toss this one out? It's a 230, so I can't honestly see doing anything other than halftones on it.


Why toss it? Nothing wrong with using it for non-halftone printing.

And you might try printing out a film of halftones and set the angle to "0".

Place it on your screen square with the frame and rotate it clockwise. As you turn it, you should see the big "blotches" get smaller. Turn it until the effect is minimized. Take the degree measurement that you turned and use that as the angle for subsequent halftone films.

See what happens.


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