Re: Color faxes have incorrect colors

Color fax uses ITULAB color space.=C2=A0 So, the received TIFFs that you'=
re
getting are using ITULAB color space.=C2=A0 Unfortunately, most TIFF and =
JPEG
viewers don't know how to properly handle ITULAB color space, and so
they mess it up.

Years and years ago when color fax reception support was introduced into
HylaFAX (2005) the plan/thought was to get libtiff and libjpeg
enhanced/modified to compensate for that.=C2=A0 There was a patch circula=
ted,
but it never made it into libjpeg.=C2=A0 And, ultimately the plan/thought=
 was
modified to just change the JPEG data colorspace before writing it into
the TIFF for portability reasons, but that was after HylaFAX+ came into
existence.=C2=A0 So, the v6.0.6 release is still using the ITULAB colorsp=
ace
in its received color faxes.

In HylaFAX+ v5.4.0 (2009) it began using LittleCMS to modify the JPEG
data colorspace before writing it into the TIFF.=C2=A0 Also, color fax
sending support was added.

To send a color fax with HylaFAX+ you can use the sendfax -O "usecolor"
option.=C2=A0 (See 'man sendfax'.)=C2=A0 You will probably need to be usi=
ng a
Class 1/1.0 modem (unless you have one of a few Class 2.0/2.1 modems
that support color) and have "Class1ColorJPEGSupport" set to "true" or
"yes" in your modem config file.

Thanks,

Lee.


On 02/26/2019 06:26 PM, Jason wrote:
> Hi,
>
> On Linux Mint 18.1 using the version of HylaFax that is packaged with=20
> the distribution (6.0.6). Using a ZOOM 3095 56K V.92/V.90 USB modem.
>
> When I turn on color fax reception with (in=20
> /var/spool/hylafax/etc/config.ttyACM0):
>
> 	Class1ColorJPEGSupport: Yes
>
> color faxes are received but have a badly messed up color scheme, the=20
> most prominent feature being a bright orange color across the whole pag=
e=20
> background and wherever something ought to be white. Do I have the=20
> wrong setting or what might be the problem?=20
>
> Another question I have is how do I *send* a color fax?
>
> Thank you.




____________________ HylaFAX(tm) Users Mailing List _____________________=
__
  To subscribe/unsubscribe, click http://lists.hylafax.org/cgi-bin/lsg2.c=
gi
 On UNIX: mail -s unsubscribe [email protected] < /dev/nu=
ll
  *To learn about commercial HylaFAX(tm) support, mail [email protected].*