Re: [hylafax-users] Receiving a color fax

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

Blas Rodriguez Somoza wrote:

>    First I update libtiff and libjpeg with libtiff-3.7.4 and 
> libjpeg-6b-36 patched. (using rpm)


I don't understand what you're saying here by the "using rpm" part.  Did 
you get libjpeg source code (SRPM), patch it, build it, install it.  
Then did you get libtiff source code (SRPM), patch it, build it, and 
then install it.  And then did you subsequently build and install HylaFAX?

Were you following the instructions here: ?

 http://hylafax.sourceforge.net/howto/install.php#ss2.5

>    Then I modify the config.ttySL0, adding Class1JPEGColorSupport: yes.
>
>    After that I'm able to receive a JPEG color fax and forward it to 
> an email account.
>
>    I try using tif and pdf format, but I can't open the attachment.


You're probably not to this point yet, but when you get here... realize 
that the TIFF will (originally) have image data encoded with a CIELAB 
color pallate.  I don't think that you're going to have a TIFF viewer 
that will represent the colors properly.  So in FaxDispatch, if you're 
going to send a TIFF image on to the recipient, you'll want to convert 
it first with tiffcp to an RGB pallate or something that your TIFF 
viewer will understand.

Similarly, most PDF viewers are not going to be able to make sense of 
the color pallate, either.  So when you use libtiff's tiff2pdf to 
convert the CIELAB JPEG TIFF into PDF (which basically just is replaces 
the TIFF wrapper with a PDF one) you'll find the colors don't come out 
right.  That's why you'll want to use HylaFAX's tiff2pdf script in the 
case of color faxes instead of libtiff's... because libtiff's tiff2ps 
utility (which is used by HylaFAX's tiff2pdf with Ghostscript's ps2pdf) 
will convert the CIELAB colors into RGB first.

Yes, it is not straight-forward... unfortunately.  The ITU made it this 
way by using an uncommon (basically fax-specific) color pallate.

> DataFormat: 2-D Uncompressed Mode 


My guess is that it says this because your libtiff isn't patched 
properly yet.

Lee.


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