May 22nd, 2006

Halftoning pictures with the GIMP for photocopies

The GIMP can conveniently complement a desktop publishing tool like Scribus; and if you are on a low budget, you can also prepare your pictures for the photocopying process by converting them to black & white halftone.

Photocopiers use powder toner, and they have a hard time reproducing grey hues. By preparing all of your documents pictures this way, you facilitate the photocopier’s work, allowing it to reproduce plain black or white shapes.

If you haven’t got the GIMP installed yet, you should be able to find a link to your OS version on the project’s web site.

First of all, make sure that you properly resize your image for black and white printing. A resolution of 300 dpi is the norm, although you could do with a minimum of 150 dpi. Basically, if you intend to send your work on a digital media (CD, DVD, USB key), you can go for a 300 dpi resolution. Otherwise, if the work needs to be sent through email, a 150 dpi image will take less than 1/4 of the disc space that a 300 dpi might.

In this example, the resolution is set to a 150 dpi.

Next, choose:
Image > Mode > Indexed

Set the colormap to use black and white (1bit) palette and choose between Floyd-Steinberg (normal) and Positioned dithering.

the original image in grey and the result in halftone

Share

Bitmap editing
Cross-platform
Open

Comments (0)

Permalink

Desktop publishing with scribus

Want to quickly create folding double-sided leaflets? Try putting it together with Scribus, a very promising and powerful desktop publishing tool

Scribus’ interface is rather similar to that of long-established Quark Xpress and Adobe PageMaker. It can import mainstream Bitmaps formats, as well as .TXT, .SVG, .EPS and OpenOffice Draw.
Scribus allows to apply individual text formattings, which can be individually edited to change the look of a long document.
It conveniently exports in Adobe’s .EPS and .PDF formats, the latter being perfectly readable by Adobe’s Acrobat Reader, but not opening perfectly in Illustrator.

Pros:

  • Open Source: no licensing fee.
  • Cross-platform: available for Windows, Mac and GNU/Linux operating systems.
  • Imports .EPS and mainstream Bitmap formats.
  • Exports in EPS.

Cons:

  • the native formats lacks backwards compatibility between the 1.2 and 1.3 versions tested.
  • Lack of import filter for Adobe .AI and .PDF formats.
  • PDF export filters are perfectible.
  • Precompiled binary 1.3 version for Windows somehow unstable. But is the blame to put on Microsoft or the source files?

I give it a three stars, the interface is a bit slow at times.

Share

Desktop publishing
Migration
Open

Comments (0)

Permalink