Re: Status of receiving color JPEG fax (sent by HP OfficeJet 8600)

On 9/1/2015 7:39 PM, Lee Howard wrote:
> On 09/01/2015 03:34 PM, Chris Coleman wrote:
>> Question. It's now 2015, what's the current status of receiving color 
>> (or grayscale... JPEG or JBIG) fax from, for example, HP OfficeJet 
>> Pro 8600 multi function fax/printer/scanner ?
>
> Short answer: you need to use HylaFAX+.
>
> Long answer...
>
> Color fax receiving support was added in HylaFAX 4.2.2 for Class 
> 1/1.0.  However, because that's how the data comes from the sender's 
> fax machine, the fax image was stored in the TIFF as ITULAB colorspace 
> in JPEG... which most JPEG-enabled TIFF viewers are not going to be 
> able to handle (or JPEG viewers, for that matter, if you were to 
> strip-out the JPEG from the TIFF).  So, for most users, it was really 
> not useful.
>
> Developments in color fax support after that point were made in HylaFAX+.
>
> Color fax support was added to Class 2.0/2.1 in HylaFAX+ 5.1.0.
>
> Color fax sending support was added in HylaFAX+ 5.4.0.
>
> Also in HylaFAX+ 5.4.0 received color faxes were converted from ITULAB 
> colorspace to YCbCr.  At that point color faxes became useful for most 
> users.
>
> Some improvements to color fax support have occurred since then, too 
> (like better page and data size support).
>
Thanks Lee!
I've installed HylaFAX+ 5.5.6 from source and am still receiving TIFF 
images that are stuck in ITULab color space for some reason so just 
wanted to ask a couple of follow up questions.

Trying to find out why the received TIFF files remain unviewable when 
they should appear fine with HylaFAX+ 5.5.6


1. I'm seeing in the online HylaFAX+ Sourceforge documentation where it 
says, just after saying that 5.4.1 supports JPEG/color fax, that it's 
necessary to still manually patch libtiff.
http://hylafax.sourceforge.net/howto/install.php#ss2.5
As of HylaFAX+ 5.5.6 the latest release version, is this requirement to 
manually patch rebuild and reinstall libtiff, outdated information, or 
is it really still necessary to manually patch rebuild and reinstall 
libtiff today in 2015?

2. In reading the bug report and suggested patch on libtiff 4.0 beta 
from late 2009/2010-2011...
http://bugzilla.maptools.org/show_bug.cgi?id=2135

I agree with your comment there, that decompressing and immediately 
recompressing the JPEG image of the color fax page is a pointless loss 
of quality and an unacceptable workaround just to generate that valid 
non-null JPEGTables TIFF tag so that the TIFF file would open with all 
TIFF viewers and convert successfully to PDF with the tiff2pdf command line.

The maintainers comment they have experienced regressions in their tests 
of your patch to fix the issue in libtiff 4.0.0, so these seem to be 
somewhat valid reasons for not accepting the patch, which shows status 
REOPENED.

Has this libtiff patch situation evolved since 2011?

3. Has some other technique been implemented for HylaFAX+ to bypass libtiff?

There was mention of using LittleCMS to bypass libtiff and its bug in 
handling JPEG images inside TIFF ?


-Chris


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