In the Print With Preview/Screen section, I've selected different frequencies from 10 lines/inch to 100 lines/inch and printed with no discernable halftoning happening.
That's correct. Halftoning only happens at the printer if you are using a PostScript printer. With an inkjet printer, you won't be able to get a halftone this way.
You can use Image-Mode->Grayscale, then Image->Mode->Bitmap and set your halftone parameters when you create the bitmap. Create it at a high resolution--say, 1200 dpi. And expect to be disappointed when you try to burn a screen from the film you get.
Inkjet ink is not opaque, especially not to the intense ultraviolet light used to burn a screen. I've tried burning screens from inkjet transparency. the result isn't pretty.
You can get decent results printing your halftone on a laser printer using UV Ultra-Transparent paper, which is similar to vellum. You'll get much better results, and save yourself a lot of grief, if you take the image to a service bureau and spend $5 on a page of imagesetter output.
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