Got a mesh interference issue myself.

[Dottonedan]

We have been doing great with screens but I've always known pre-stretched statics and even Panel frames often don't come "perfect"or tend to provide mesh interference issues at certain %. due to a particular size dot being in the sweet spot for interference.   I believe right now, I'got a batch of screens in that have  an issues of not being perfectly aligned warp and weft. Now mid ya, I'm not always expecting perfection for mass stretching production areas. Like printing, the water and more you need to do, the less careful we humans are.   But in this case, It seems to have happened far too frequently. Perhaps, my issues is not even mesh angle stretching related.  Fact is, I've had no issues with the screen angle we use...nor mesh to lip issue.


With the most recent issue, (a group of screens), I have used a 50lpi on a base white of a 230 mesh.  The area is a solid area of 20% filled tone.  Getting mesh interference/patterns.  So we go up to 280. Same thing. Go up to 305 (same thing).  All look different, but still an unwanted pattern. While the screens were each different, they still had the issue...but each had the same %.  So I upped the % to 30% fill and it is gone.  So (it needed a larger dot).


A couple jobs later, needed to print black on a job with a complete coverage of 20% black.  Same issue.  (For a white ink, on a base, we can bury it a little but with black on 230 mesh, can't do that.  So.  I then took out the soup and took some pictures of some bad screens. Here is one of them.  I can see the angle is off.  But really, is it off "that far" to have caused my issues?


I was considering mesh coating. Maybe too thin?  It's a 1"1 dull side on 230's and up.  (people are all over the place on technique for that) but these are very very smooth and consistant). Just a tad on the waffle texture. A tad.


The only thing I can see up close is that there are 4 open areas in some, and mostly 3,  with a few areas that are 1-2.  I traced the angles and yea, they seem off, and this area is probably near .25 inch wide (guessing). So when you look at the angle from top of screen to bottom of screen, the angle can be very far off. Like an inch off vertical.  Too much?  Do you think this is my issue?

[Dottonedan]

Couple other pics.

[cbjamel]

Dan what angle are you doing the dot 22.5? i had problems with it i went to 25 degrees solved a lot of problems for me...
For me.
Shane

[Dottonedan]

I am using 22.5.   I figured it was an angle thing and created an angle test sheet. I did a strip, of tonal squares, 1.5"tall, and printed that out multiple times on the same sheet of film, just moving it down each time. SO I can get one good burn and see where the best angle will be.


The problems with that is, I don't think it's going to be a consistent problem solver. For example, I feel that most screens meshes will enable me to use 22.5 better, and maybe some screens will enable me to use 25 better.  Changing the percentage has worked here and there, but that's not a good answer either. We want a 20% to really be close rot 20% when printed. Not 30% for example.

[3Deep]

sorry to say Dan, your not going to get what you want every time just close, #1 difference in screens mesh itself from run to run even if you buy from the same company, #2 stretching of the screens and getting the mesh square, #3 Emulsion inconsistent and how it put on ( slow coating, fast coating etc).  #2 is what gave me fits trying to work with roller frames I just wasn't good at getting the mesh square so mister moire was a good friend of mine LOL

[RICK STEFANICK]

Dan, Just for grins try moving your film so its ever so slighty NOT square on the screen and reshoot with the same 22.5, mesh and exposure time. I'll bet you problem is solved.

[tonypep]

Or CTS