Halftone bitmap frequency

[jimmyp]

Hello!

Unfortunately I don't have the time to do any test prints for this poster—so need to make sure I'm going to get the results I want before I order my positives.

I've never tried to use halftone dots in printing before—I've always just kept it simpler.


Here is an element from the poster, scaled down in size, unfiltered. Obviously I want to keep it close to this.



Here is the image at 100% size, unfiltered (right click-view image to view full size).



And here is the image bitmapped, with a round halftone screen, frequency of 30 (right click-view image to view full size).

Obviously when printed out, the dots are a lot finer.

I'm using a 120 mesh screen.

I'm printing this black on silver, on white paper.

Will the small white dots expose and print? Can anyone give me some expert advice? If all else fails, I can sign up for a printers in Leeds—but would rather not pay £60 for a few test prints. Of course, I will if I have to.

Thanks for reading my poorly written plea for help,
James.

[lil_tuffy]

Is the silver going to be a half-tone?

120 might be ok for the metallic but I'd definitely go up to 230 or 305 mesh for the black.

[vastagh]

you're gonna be bummed trying to print that with a 120.

go premium until then.

[Dan Apparatus]

Your line screen capability is your mesh count divided by 3.5. So if you have a 120 mesh screen you would be capable of roughly 35 dots per inch. That'll be pushing it though and you might get a moire pattern. I'd try and make a halftone screen that is 30 dpi or less to be safe.

[jimmyp]

The silver is just going to be solid, with black halftone over the that.

Your line screen capability is your mesh count divided by 3.5. So if you have a 120 mesh screen you would be capable of roughly 35 dots per inch. That'll be pushing it though and you might get a moire pattern. I'd try and make a halftone screen that is 30 dpi or less to be safe.

So I was right with the frequency of 30 lines per inch?

Anywhere I've printed, the highest mesh screen has always been 120. Guess it's time I bought my own screens…

[vrooooom]

The original looks more like a dither, so why halftone it? Stochastic would be nice. Is your 120 screen US standard, or 120 t/cm? You'll need a fairly fine screen to get nice, stochastic dots.

[Andymac]

!!!!! - are you talking threads per inch or threads per centimeter? European measurements are different than American, and Americans tend to think everything everywhere is like theirs.

230 in North America is 90 in Europe. 120 in Europe is 305 in American. You would be hardpressed printing silver through that. for halftones w/ black not a problem.

30 lines per inch on the halftone is pretty chunky, you should be good - look at your stencil after the burn to make sure you got all the detail, and use a sharp squeegee.

[Andymac]

and tha's why they call him Vrooom, because he's so damn fast with the response....

[vrooooom]

and tha's why they call him Vrooom, because he's so damn fast with the response....

^_^

[jimmyp]

Ha, I was just searching mesh sizes on the forums.

Okay… right.

I'm using a 120 size mesh, CM. I was thinking it doesn't get much finer than that.

I'll be using a 60 for the silver.

Okay, great. Phew—this is what I get for eating space cakes last night.

So, I'm totally cool with a 120/305.