 Re: How do you setup actual picture designs for screen printing?
Use a high mesh screen (305) and low lpi (lines per inch, changes dot size) of 55 lpi or lower. Higher looks better, but is harder to print, lower is easier but you can see the dots better (which you don't want).
I assume your printer doesn't do dots, or you wouldn't ask about how to halftone. So use your photoshop or photopaint to do the halftoning.
Convert to grayscale first. Make sure your image is the right physical size. In inches, that is.
Then set your resolution to at least 300dpi, but preferably to 600 or 800.
In photoshop, convert to bitmap, in photopaint, convert to black and white. To use a certain lpi (like 55) in photoshop, you have to calculate how many pixels fit in a line. You simply divide the resolution you just set (600dpi?) by your line count (55) and get (in this case) 11 pixels (rounded). It is advised to use a resolution at lest 16x the line count, because then each dot has 16x16 pixels which is 256 pixels, so that all 256 gray tones have a dot with matching area and you don't lose fidelity.
Good luck. | 
