[texhax] Illustrations from other books
William F. Adams
wadams at atlis.com
Mon Sep 26 15:34:16 CEST 2005
On Sep 25, 2005, at 1:22 PM, pierre.mackay wrote:
> I suggest photography for any half-tone in which you can sense the
> screening, because direct scanning tends to give you a very precise
> picture of the screened dots. 300 dots per inch is all you need for
> half-tones, but if you want really sharp black and white line art, you
> will have to learn some techniques in GIMP and work from as much as
> 1200 DPI.
It's important to note that these figures are for 100% of output size.
Also, it's often worth going higher if the image has fine details or
> Issue 23.1 after page 93 will show (Figures 4 and 6) what the risks of
> getting too precise a picture of the half-tone screen are.
It's better to de-screen any already screened half-tone if you're using
greyscale, unless doing a dot-for-dot scan and output is feasible.
Some scanners have decent automatic options for this, or one can do the
- scan at the original output resolution (this captures all possible
- do a gaussian blur using a number of pixels slightly less than the
factor of the intended output dpi to the original dpi. (so if one has
1200 dpi original and is outputting at 100% @ 300dpi, blur using ~3.75
pixels for a sample)
- downsample to the output resolution
- do not sharpen much if at all (you've already captured the
sharpening applied to the original before output)
Better still is to get a new photo of the original or use a dot-for-dot
scan --- if you can find the original galleys for a book the latter is
an excellent option.
William Adams, publishing specialist
voice - 717-731-6707 | Fax - 717-731-6708
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