Checkered patern?

[Binkspot]

What is causing the checkered pattern on the top and most visible on the 2747 cup and bottom, Moire?  Fix, another screen or art work?
Have some down time on the press today and just playing around but would like to nail it.

Thanks in advance

[inkman996]

I have had that happen as well and never really figured it out. If I recall tho it seems most predominant with black inks. Its like the ink gains more and less in certain areas of the mesh.

[blue moon]

several options,
1. bad black screen
2. two different lpi used (not likely in this case)
3. garment weave interference

can't think of any more, but I am sure there are. . .

pierre

[cbjamel]

I would call it moire, for a better term. ie the black mesh at a bad angle  or sep at bad angle maybe.
My thoughts.
Shane

[tonypep]

higher mesh will fix this many printers use 2 blk inks.Low mesh for solids, high mesh for h-tones. For high mesh process blk works better

[3Deep]

Just looking at it that looks like to me the screen has clogs in it which is causing those checkered spots, I would print that black screen on a white shirt and look at the pattern.  I've had screens where I thought I had wash it out good and found out I did a piss poor job and sometimes clear emulsion runs back down in the halftones which cuz scumming.

Darryl

[Parker 1]

Try a different screen, with a different mesh count if possible every time this happens to me it has something to do with the mesh interfering with the halftone angle. (mesh could be tensioned wrong or not square in the frame) Also see it when the wash out is rushed with too much pressure on the screen for too long.  One other time something crazy happened with my RIP and I had a different lpi than the others, I could only see the minor difference using a 10X loupe.  Good print and I would like to see a pic following any changes.

Chris 

[aauusa]

that is moire,  you could have a conflict between the LPI and the mesh.  You could burn with a different mesh count screen and may go away or reprint the film with a different LPI and reburn on same mesh screen and it should go away

[Binkspot]

Thanks, printed just the black and it is in the screen. Burned a second, same mesh count (305) and have the same type of pattern. Going to try a 280 in a bit and see what happens.

I hate to pull the screen, I know it's not perfect reg yet but thats where I'm at with no micro.

[abchung]

Are you using a multi source exposure unit?

There are also moire patterns on the bottom label as well.
For me, I would use 2 screens. One for black without the label back ground and one for the label background. That way I can increase the tonal value of the label background and print with a grey (i.e softer black) or more transparent black.

Also increase the EOM to reduce unnecessary dot gain.

[BP]

 X's your lpi by 4.5 and that will tell you what mesh count to use. if you still have a problem then change your angle. try a angle of 22

[Binkspot]

3140 single point using WR-14.

I would love to add a hard black but already at 7 colors including an under base plus the flash on an eight color press. And once again my argument for needing a 14 color.

Just burned a 280 and the pattern is gone. I'll throw it in the press and see what happens.

[Colin]

You are experiencing both Moire in your screen and heavy dot gain from printing your black.

What LPI are you outputting at?

Follow the above directions for LPI/Screen mesh/angle.  55 lpi should expose just fine on a 305 mesh. 

[inkman996]

You are experiencing both Moire in your screen and heavy dot gain from printing your black.

What LPI are you outputting at?

Follow the above directions for LPI/Screen mesh/angle.  55 lpi should expose just fine on a 305 mesh.

Colin riddle me this, why does this seem to happen mostly with black half toning? Something to do with the ink and how well it is round maybe?

[Binkspot]

I think I got it, need to dial it in some more and play with pressures. May have to re do another screen. Still have a little pattern with the 280 but just playing right now. Besides the artist is on a field trip so I'm kind of held up anyway.  I really do appreciat all the help.