[APlusDesignsInc]

I am almost out of options. We have done this print over 1,000 times on dozens of different orders over the last couple years. We have always done everything the same and never had this problem. It's hard to see in the attached pic, but there are horizontal lines running through the gray print. (The print is white, gray, gold, and green). I put it next to a print from a previous order so you can see the difference. The print with the lines is on the right in the close-up pic. It's on the left in the pic of the full design.

Previously we have always used the same film, same mesh count (230) First I reprinted the film, thinking it would have been faded. That didn't work. So I tried different mesh counts. That didn't work.

I don't get it. I have never had this problem with this print.

So, now I have printed the film again making the dots bigger and changed the shape. Waiting for the screen to dry to try it again.

The only other variable I can think of is that the bulb in our exposure unit is getting pretty old.

Any other ideas on what might have caused this would be appreciated.

 

[emet214]

Looks like a moire pattern
1. When printed halftone screen angles conflict, THAT'S A "MOIRÉ"!
2.https://www.behance.net/gallery/17504107/The-Constitution-of-Moir-Silkscreen-Print
3. ink levels low in cartridge

 

[APlusDesignsInc]

The films were plenty dark. I thought it might be a moire as well. But, I have used this film with the same mesh count many times. And never had it before.

With the changed dot size and angle, I still get the same lines.

I do like the gallery you sent. Those are some cool prints.

 

[VaporApparelSC]

Looks like it wasn't wash out completely. If you look close you can see that there are definitely some missing halftones. Do you have someone new washing out screens or coating screen.

 

[Ripcord]

What screen angle did you use? Contrary to almost everything I've read over the years, I've recently found by experimentation that good old 45° produces the least moiré. And I use the same angle for multicolor work.

 

[APlusDesignsInc]

Really? I will have to give that a try. I stick with the 22.5 for all colors. Which works most of the time. I have read articles about having 4 different angels and all that, but 22.5 has worked for me.

With this design, I ended up taking the screen and power washing the crap out of it. That reduced the pattern to almost nothing. Nothing that any customer would notice anyway.

But, I will try the 45 degree angle next time I have trouble. Thanks for the tip.

 

[APlusDesignsInc]

And, yes Jimmy you are probably right. After power washing, the lines were reduced to almost nothing.

And, that is funny you asked because yes, I do have a new guy burning and coating screens.

 

[VaporApparelSC]

I have had problem with new people before. Takes some time for them to get it right. Just work with them and explain why something was wrong and what to look for when washing screen. But if they keep making same mistake over and over after you have explained it, you might want to move them a different area or get rid of them all together. Will save you a headache.

 

[Ripcord]

I used 22.5° too for many years, based on all the articles I had read. About a year ago I started thinking about it and decided to try an experiment. The threads of the mesh are what interfere with the dot pattern and they run at 90° which is the reason I wanted to try 45° for the screen.

Here's a photo of a print I made with my test screen. I used two angles and two dot shapes. The quality of the photo isn't very good but you can see the difference....

 

[APlusDesignsInc]

Wow. 45 round looks the smoothest. I would have never guessed that.

 

[Ripcord]

The round and ellipse aren't that different but after staring at it for awhile I decided the ellipse seems to hold the lighter end of the fade just a tiny bit more...

This was on a 156 mesh screen.
.

 

[sherylyo]

Line on tshirt below or above the print. I am working on poly shirts 400f 33 sec. The actual print is fine but either the edge or below the image, maybe the edge of the paper I keep getting either a bight green line or a blackish one. Any ideas?

 

[Ripcord]

Line on tshirt below or above the print. I am working on poly shirts 400f 33 sec. The actual print is fine but either the edge or below the image, maybe the edge of the paper I keep getting either a bight green line or a blackish one. Any ideas?

You might want to start a new thread for this so people will see your question. This thread was about halftones on screens...

 

[dlanthripe]

How many bulbs are used in your burn table. I had one that used florescent bulbs, 5 of them. It would make a mess sometimes with halftone super fine detail. My single bulb table does way better.