How to send legible faxes?

Question

When sending faxes, the receiver always says that the fax is illegible... What the best dpi, contrast, brightness, etc (when scanning) in order to send a legible fax?

PS: I'm using Win7's built-in fax software. I don't know anyone that owns a color fax machine to receive faxes, then I need to send black/white or grayscale option. Thank you!

Answer 1

Oh, you're scanning something into Windows and then faxing it out from there.

Remember that fax technology only supports 1-bit color depth. There is no greyscale. So set your scanner to do that and then tweak the preview until you can read it.

Answer 2

I always set my fax machine to "superfine" resolution, which seems to help a lot, assuming the other end supports it.

These are the supported resolutions, according to Wikipedia:

• Horizontal: 100 scan lines per inch
  • Vertical: 100 scan lines per inch
• Horizontal: 200 or 204 scan lines per inch
  • Vertical: 100 or 98 scan lines per inch ('Standard')
  • Vertical: 200 or 196 scan lines per inch ('Fine')
  • Vertical: 400 or 391 (note not 392) scan lines per inch ('Superfine')
• Horizontal: 300 scan lines per inch
  • Vertical: 300 scan lines per inch
• Horizontal: 400 or 408 scan lines per inch
  • Vertical: 400 or 391 scan lines per inch ('Ultrafine')