i would go 30-50 dpi with a 180 meshes.

we use 55 LPI / 21 degrees for 305 mesh at the high end on the auto presses, but you probably don't want to use 305's for manual printing - it's too hard to squeegee the ink through those tiny holes in the mesh.

but using that same ratio - 55 lpi to a 305 mesh - you'd get the following:

36 LPI for a 200 mesh
32 LPI for a 180 mesh
19 LPI for a 110 mesh

which sounds about right. in reality, if you are very careful about coating and burning your screens, you could reproduce higher line screens, but with most home set-ups you won't be all that accurate.

it's important that you use an odd angle on your halftones (21 deg is good) to minimize the chances of moire patterns showing up in the prints. use the same angles for all your spot colors.

also, if you can lighten up your darks a little - i.e. use curves in photoshop to boost the lower-mid values on your halftones - your halftones will reproduce more accurately. with most manual printing, anything above 92% ink coverage will probably close in and look solid, unless you have a low LPI for the screen you're using (i.e.: a 35 LPI halftone on a 305 mesh)

hope this helps!

Alan, the rule of thumb is to divide the mesh count by 4.5 or to find the correct lines per inch.

110 tpi = 24
137 tpi = 30
156 tpi = 34
195 tpi = 43
205 tpi = 45
230 tpi = 51
305 tpi = 67
330 tpi = 73

On the other hand, if someone gives you the art that is already output you can multiply the lines per inch by 4.5 and then move to the closest mesh count that will work for you. I would suggest going up rather than down.

The most used screen angle in the industry is 22.5 degrees from 0 on all colors, whether spot, process color or simulated process.

Bill Hood
School of Screenprinting
schoolofscreenprinting.com