[OS X TeX] Preparation of illustrations for press

Alan Litchfield alan at alphabyte.co.nz
Tue Mar 25 16:15:57 EDT 2008

Hi Adam,

Adam Fenn wrote:
> I would some advice on how best to prepare illustrations for press. I
> note that publishers such as Springer typically recommend minimum
> resolutions of  300, 600, 1200 dpi for
> halftones, combination art and line drawings respectively.

Yes, those are standard figures. So too are 3600 and 4800 dpi but these are
used to make the plates.

> So far I have a few full colour illustrations, approximately 10 x 15
> cm, scanned at 800 dpi and saved as pdfs in photoshop. This produces
> quite large image  files, around 24MB, and both TeXshop preview and
> Acrobat Reader take a long time todisplay these pages (I realise that I
> can use draft mode when working on the text).

There is no point in having your images scanned at 800 dpi. The platesetter
will only work with 300dpi images, however if it is your intention to have
these printed in high quality colour then I strongly recommend that you have
them scanned professionally. The prepress outfit you are working with ought to
be able to replace the scans you generate in your pdf's with hi-res scans at
plate stage. The difference lies in the bit depth at which the scans are made,
and your little desktop scanner simply does not have a good enough ccd to do
the job. The best it is likely to achieve will be 8-bit per pixel but high end
scanners are capable of 24-bit, plus, which means they can grab far more
accurate colour information per pixel.

Note too that while the common understanding is for images to be scanned and
saved in CMYK colour mode that is not actually necessary. For example most
high end scanners scan using RGB and in general, most platesetters are more
than capable of converting RGB to CMYK without loss of quality.

Saving your scans as pdf is fine. Use 300dpi CMYK or RGB.

> Is this the best way to prepare illustrations for press? Should I save
> them in a format other than pdf? Is it normal for pdf files with lots
> of high resolution illustrations to be so slow to display or is this
> more an issue with the amount of memory on my computer?

Once I would have said only use TIFF for scanned images, and in most dtp
packages that is still the way to go, but pdf acts as a wrapper for the raster
image and is also able to include far more data about it, so pdf is good.
Anyway most of the Adobe graphics/publishing products are using pdf as their
internal file format and export to others like eps and tiff these days.

Good luck with the project.


Alan Litchfield MBus (Hons), MNZCS
PO Box 1941, Auckland

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