Figure formats

Figure formats

[Jörg Hagmann]

Dear list members,
If you have the choice of format when preparing the figures for a book 
written with ConTeXt, what would you opt for? (The figures are being 
drawn with ChemDraw and Illustrator).

JPEG, TIFF, eps etc, or doesn't it matter? Should the figures be drawn 
at exactly the final size, or is resizing when setting ok? Other 
suggestions?
Thank you for the help, Jörg.

PD Dr.med. Jörg Hagmann-Zanolari
Institute of Biochemistry and Genetics
DKBW, University of Basel
Mattenstrasse 28
CH-4058 Basel
Switzerland
Phone +41 (0)61 6953049

Re: Figure formats

[Hans Hagen]

Jörg Hagmann wrote:
> Dear list members,
> If you have the choice of format when preparing the figures for a book 
> written with ConTeXt, what would you opt for? (The figures are being 
> drawn with ChemDraw and Illustrator).

vector graphics : pdf (or eps converted to pdf)
b&w bitmaps     : png
color birmaps   : jpg medium/high

> JPEG, TIFF, eps etc, or doesn't it matter? Should the figures be drawn 
> at exactly the final size, or is resizing when setting ok? Other 
> suggestions?

as long as you have >=600dpi scaling is seldom a problem

Hans


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Re: Figure formats

[Mari Voipio]

Jörg Hagmann wrote:
> If you have the choice of format when preparing the figures for a book 
> written with ConTeXt, what would you opt for? (The figures are being 
> drawn with ChemDraw and Illustrator).

I'm not terribly good at this (yet?), but one my main guidelines in this 
kind of situations in and out of ConTeXt is to keep vector graphics in 
vector format and only use bitmap graphics (like png or jpg) if the 
original is in a bitmap format (like a photo).

I handle mostly graphics that originate from a 3D CAD program and 
different types of graphics I draw myself in CorelDraw (equivalent to 
Adobe Illustrator as far as I know). These both generally produce vector 
drawings The drawings from the 3D program are mostly in pdf format when 
they arrive to me and I've found, somewhat to my surprise, that the best 
way of handling them seems to be to include them as pdf, just to crop 
them to the picture itself. I also turn my CorelDraw pics into pdf 
before adding them to ConTeXt based text, that inserts them nicely and 
makes it easy for me to share any graphics at request (I'm occasionally 
asked to send just graphic 3.1 from manual x, so it is a good thing to 
have all of them as pdf).
The nice thing with vector graphics is that they are almost indefinitely 
scalable, so the size of the original is not so critical - and the files 
don't take much space even when the original is bigger than the graphic 
in my book.

Whenever I have to do something with bitmaps, I try to scale them close 
to the final size with good graphics programs, I feel that this give me 
better control over what happens to the graphics when resized (the 
resolution of some of the originals is pretty bad...). On the other 
hand, if it doesn't look bad in the final product, why bother...

Greetings from Finland,
			Mari

PS. Here's a manual [all public] I've done by using text in ConTeXt and 
vector graphics in pdf and bitmaps in jpg/png: 
<http://www.kpatents.com/1Library/manuals_pr-23.htm>. For example 
chapter 5 (at 
<http://www.kpatents.com/1Library/manuals/pr-23/pr-23_05.pdf>) has 
mainly screen capture bitmaps (I used png format) and chapter 4 (at 
<http://www.kpatents.com/1Library/manuals/pr-23/pr-23_04.pdf> includes a 
ton of drawings originating from our 3D CAD.

Re: Figure formats

[Ville Voipio]

> them to the picture itself. I also turn my CorelDraw pics into pdf 
> before adding them to ConTeXt based text, that inserts them nicely and 
> makes it easy for me to share any graphics at request (I'm occasionally 
> asked to send just graphic 3.1 from manual x, so it is a good thing to 
> have all of them as pdf).

An interesting thing is that sometimes some programs make stupid
mistakes when exporting to PDF. For example, I have had some
bounding box problems when exporting to PDF. The bounding box
tends to be the size of a page, which is really not a nice thing.
(This happens with CorelDraw 11 in OS X and with older CDR
versions in other OSes.) Illustrator should be safe, as PDF
is one of its "home" formats.

A workaround which I've been using for years is to export in EPS.
All graphics programs I've come across have been able to do that
reliably. Then the EPS can be converted into a PDF by using one
of the following: a) Adobe Distiller b) Ghostscript (epstopdf,
eps2pdf, or equivalent) c) Preview in OS X.

I have found it very useful to have all illustrations in PDF
format in the right size (i.e., clipped to the right size,
correct bounding box). Then it is easy to play around with them.

Even though vector graphics is -- in theory -- infinitely scalable,
in practice it is much better to try and draw the pictures 1:1.
If the images are scaled, line widths and annotations are scaled,
too. Especially when there are several similar pictures with
different scale factor, the result looks odd. So, the final size
of the illustration should be known before drawing the actual
picture!

It is also a good idea to scale the bitmaps down (or up) to the
final size and resolution before inserting them. This avoids
a number of strange problems when rendering the images. For
photographs, 200 dpi should be enough almost always, line art
requires 300 dpi. (And a very important exception is that all
screen captures should be taken "as is" without any operations
on them.)

Too large a resolution makes the files unnecessarily large and
slow, so even that should be gotten rid of. Graphics packages
have different resizeing algorithms, and getting to know all
of them takes some experimenting, but it is well worth the trouble.

What comes to the figure formats, PNG is good for lossless images
(screen captures) or images requiring alpha channel. JPG is best
for photographs and other continuous-tone real-world images
(and some visualizations). But, whenever possible, use PDF, if
there is any choice.

- Ville