[pdftex] Colour profiles and pdftex

[John Culleton]

On Sunday 06 September 2009 08:04:03 George N. White III wrote:
> On Sat, Sep 5, 2009 at 6:09 AM, André 
Bellaïche<abellaic at math.jussieu.fr> wrote:
> > Hello,
> >
> > I have gone into many troubles with a printing house recently 
about
> > colour profiles or workspaces of included illustrations. The 
printer
> > complained very much about colour profiles for image files 
embedded in
> > the pdf file, although the book was in black, and all the 
illustrations
> > had been converted to black and white or gray level.
>
> Grays can be very difficult to get right.  If you have images such 
as
> photographs where certain details need to be visible in 
(photocopies
> of) print versions, then you need either a very cooperative 
printer
> (almost impossible to find) or you have to take full advantage 
of
> the prepress tools for color management.
>
> > These profiles or workspaces have names as Fogra 27 or Dot 
Gain 15%.
> >
> > I know nothing about the subject, and could hardly find 
something about
> > it on the Web, or in the books about Illustrator and Photoshop 
you can
> > find in bookshops. So, these are my questions.
> >
> > 1) Where can I find both general and precise information 
about the
> > subject (books or url's)?
>
> Standards such as PDF/X are designed to make prepress more
> reliable in automated workflows.
>
> americanprinter.com: tends to be wieghted towards product 
advertising, but
> contains useful information and is read by print shop staff.
>
> 
<http://americanprinter.com/prepress/color/printing_implementing_color_mana
>gement/>
>
> wikipedia.com: PDF/X, "ICC profile"
> Google: site:adobe.com PDF/X "ICC profile"
>
> Book: "Exploring Digital PrePress: The Art and Technology of 
Preparing
> Electronic Files for Printing" by
> Reid Anderson
>
> > 2) Is there a default profile included by pdftex in the files it
> > produces? What does pdftex do with the profile of included 
images, which
> > can be of various sources: Adobe Illustrator, Photoshop, 
Mathematica,
> > Geoplan... ?
>
> No.  In N. America many shops assume SRGB if no profile is 
provided.
> Many LCD displays have an SRGB setting that is adequate for 
simple
> tasks, but for careful work factors such as age and ambient 
light will
> affect colors.  You will have to save the illustrations using a tool 
that
> supports the appropriate PDF/X standard.
>
> See <http://www.tug.org/pipermail/pdftex/2003-
October/004490.html>
> for an example.  You can use Adobe Apps to create PDF/X.  
Unless your
> use of color is very simple, you should invest in a colorimeter 
such as
> Pantone Huey, which will help to ensure that the printshop sees 
the same
> colors you do.
>
> > 3) Is there a way to change the default output profile of 
pdftex to get
> > more bold printing when one uses the Knuth Computer 
Modern fonts, which
> > prints much to pale in most cases?
>
> No.  The fonts were designed that way, but some print shops 
have problems
> with the thin lines (dropouts).   There are other fonts that may 
be more
> suited to a particular document, but the choice is limited if you 
need
> maths.  There are some documents on CTAN that compare the 
options for maths
> using Type 1 fonts.
>
> > André Bellaďche
>
> These days, print shops expect authors to do much more of the 
work.  It is
> difficult to achieve top quality using only free tools.   Most 
shops are
> used to working with documents created using Adobe tools, so 
it is
> generally a good idea to save all the illustrations with the 
appropriate
> Adobe tool.
Just FYI:  For book covers the printer LSI wants PDF X/1a:2001 plus 
ink coverage no greater than 260%  (The usual max is 300%)  
Their tech told me that X/3 (popular in Europe) will mess up their 
work flow.  LSI is the only economic avenue to Amazon, the 
dominant on line book seller.  Therefore small and self publishers 
are pretty much tied to that very restrictive standard. 
 -- 
John Culleton
"Create Book Covers with Scribus"
http://www.booklocker.com/books/4055.html