[pdftex] Best bitmap image format?

gnwiii at gmail.com gnwiii at gmail.com
Sun Feb 26 19:51:52 CET 2006

On 2/26/06, Hans Hagen <pragma at wxs.nl> wrote:
> Reinhard Kotucha wrote:
>  > I agree with everything you said and I also recommend to use PNG for
>  > screenshots. However, someone on this list reported that his
>  > publisher required CMYK colors in included graphics which is not
>  > supported by PNG. Maybe Hans had this in mind.
> indeed,
> when we have to deal with dealing with professional printing png is a
> no-go and only jpeg compression (lossy) and tiff compression (lossless)
> make sense; pdftex only supports jpeg inclusion natively, so in the case
> of screen dumps, the other alternative is to save as tiff and convert
> that to cmyk (in an editor) and then pdf before inclusion (actually, we
> always convert to be included images to pdf first, mainly because
> inclusion of pdf is much faster)

ImageMagick does RGB to CMYK, and also (when built with lcms) ICC
profiles, so in the rare cases that an image doesn't need other
touch-ups it is possible to avoid the editor.

Inclusion of pdf is not only faster, it is reliable.  Pdftex is not an
image processing application, and there are many more people doing
image processing than have heard of TeX.  In my work it is far better
to deal with conversion issues on an image-by-image basis where you
can choose between jpeg or lossless (LZW) compression, color-space
compression, changes in resolution, etc. according to the image
contents.   I suppose someone doing a catalog with 1000's of images
with similar characteristics can't afford the image editor step.

> > And it's worth to try
> >
> >    http://www.inf.bme.hu/~pts/sam2p
> interesting; buy why no rgb -> cmyk conversion; i'll give it a try
> anyway -)

In science, we have to pay extra for each color image that is printed,
so CMYK color images are used sparingly in typeset documents and the
image editor is a good tool.  For the rest (e.g., web documents),
(s)RGB is used.  The main need for command-line tools is with RGB
images, so there is not going to be a big rush to support CMYK.

The rush is, however,  _ON_ to support more bits-per-pixel and image
metadata (like geotiff).   People need to interact with images in
electronic documents (pick geographic locations in georeferenced
images, zoom in on a selected region without zooming the whole page,
adjust brightness and contrast for individual images).  Will pdf-2
support this?  Imagine the conventional atlases being replaced by
electronic versions with a Google Earth type of interface but much
more metadata.

George N. White III <aa056 at chebucto.ns.ca>
Head of St. Margarets Bay, Nova Scotia

More information about the pdftex mailing list