question about halftones and discharge

[ericheartsu]

I'm re setting up a one color white print later today, and i'd like to print it with Discharge ink. The image is a b&w photo, and is heavily halftoned.

I was going to use a 272 mesh screen, with a 2/1 thin coat of emulsion, but i'm wondering if it would be better to use a thicker coated screen?

On my earlier tests i was getting alot of grid like patterns. I was wondering if one of you guru's of industry, could point me in the direction of getting rid of that?

[Frog]

My answer is not related to discharge ink, but rather just plain old halftone screen and stencil guidelines.

The "grid" sounds like a moire interference pattern.
That can be caused by too fine lpi and/or a bad angle in relation to the mesh.

I'd go with a 55 (but 60 is certainly still within the usual limits), and an angle of 22.5 or 25

What did you use?

[blue moon]

on a 272, try a 45lpi at 22.5 degrees and see what you get. You can burn just one screen so you get a sense of the final product. If it looks good, move up and try 55lpi. If it does not look good, figure out the problem and fix it. If you post the pictures we can try to help.

You can also print the attached file as a test of your RIP and what you are holding on the screen.

pierre

[ericheartsu]

I always have a hard time attaching pics here. i'll try and get them up this weekend.

[Frog]

I always have a hard time attaching pics here. i'll try and get them up this weekend.

Often, when someone has said that in the past, and I get the file, it's a huge high resolution version. Remember that 72 dpi displays just fine. (but can still be too physically large)

[GaryG]

Make sure the highlights are cut off at 5% on the low end as a starting point.
Also, make sure you have enough pressure getting
all the dots out. Sometimes weak spray on highlights can
hit and miss causing the grid or sawtooth.