Dither vs Halftone

[rainsux]

I need to convert ~18,000 B&W, vector PDFs to a dithered or halftone'd 1-bit PNGs. The
goal being to get a reasonably useful image for the current crop of ebook readers.

Example of a source document:

http://naco.faa.gov/d-tpp/1002/00443I1C2.PDF

I have scripted all of the various -ordered-dither masks ... and the results are bad,
seriously bad.

I have also Google'd for info re: halftone'g ... not much useful info.

I am out of envelope and out of ideas. Anyone able to provide a few breadcrumbs
that can get me on the correct track?

TIA,

-doug

[rainsux]

N E V E R M I N D . . .

I have discovered -density

-doug

[jbierling]

Digging this thread up from its grave, I'm wondering why the OP thought density would solve his halftone/1bit/dithering output problem. Density doesn't affect the image at all, it just changes the desired resolution of an image for rendering to a device.

Ideas?

[fmw42]

Because you need to tell a PDF what density to read it in. Vector files have no specific size until a density is assigned to it. The density given to the PDF will affect any raster image into which the PDF is converted. If the density is too low, the raster image will be very small and thus very coarse. Dithering looks different depending upon the image size.