Re: More GIF/JPEG/PNG Discussion

[jeremy@xxxxxxxxx (Jeremy H. Griffith)]

On Tue, 21 Sep 1999 14:18:21 -0700, Tom Regner <tom_regner@net.com> wrote:

>Donna & Jeremy,
>
>It has always been my understanding that it was Compuserve who came
>up with the 8-bit Graphics Interchange Format (GIF), long before their
>use became vogue on the WWW.  

You are correct.  The issue is not the GIF format itself, but the
default compression method used in it, LZW compression.  The "W",
Welch, was an employee of Burroughs (or Sperry?), a predecessor
of Unisys, when he made the final LZW tweaks.  He published his
work in an international math journal, and said nothing about any
patent; everyone thought it was public domain, and in fact at that
time there was a strong belief, supported by the US Patent Office,
that algorithms were *not* patentable, only hardware that made use
of them.  So when Unisys patented LZW, it was bleeding-edge law...

>There has never been a licensing issue,
>and I'd like to see solid evidence that a.) Unisys does in fact now own
>the rights to the format and have established a copyright for something
>that has been a de facto (if not de jure) standard on the Web since its
>inception.  It might be true... but for the sake of these discussions I
>will resolutely claim my origins as Missouri (the "Show Me" state, for
>those abroad who might not get the reference).

I guess you missed the very public outcry when Unisys first asserted
that anyone using GIFs had to pay them...  CompuServe took the lead
in negotiationg with them on behalf of the user community, since they
were the most obviously affected.  The agreement they appeared to get
was that Unisys would *never* ask royalties for owning or viewing GIFs,
but only collect from software manufacturers whose programs created
GIFs and were commercial.  (The license terms, BTW, are both confidential
and Draconian; we looked at getting a license, and decided not to; that's
why mif2go doesn't have anything to do with GIFs.)

More recently, Unisys reneged on this, and announced that they wanted
a hefty ($5K to $7.5K) royalty for use of GIFs on a Web site:
  http://corp2.unisys.com/LeadStory/lzw-license.html
While they appear to offer exemptions for those who can prove *all* the
GIFs on their site were made by software from licensed vendors, there
is a big exception to that; it depends on the *exact* terms of their
license with the vendor, which they will not disclose.  (The vendor, BTW,
would have to violate a confidentiality clause in it to give you a copy.)
So you're fine... if your lawyer can inspect an (unavailable) contract
between two other parties, and certify that it protects your *particular*
use of the images.  When we pointed out this problem to Unisys' General
Counsel, during direct emails, he declined to clarify the issue... just
thanked us for our comments.  Hmmmm.

>The reference to PNG format is interesting, but there are not a lot of
>tools out there for making these odd beasts. (I'd like to see some
>examples of how they work with FrameMaker, btw.)  PNG files are
>perhaps the very best in terms of quality-to-file size (they don't
>look nearly as lossy as JPEGs for the same compression factor), but
>we still don't see many of these files out there despite the fact that
>most common browsers support the format.

The problem seems to be that the browsers do not support all variants
of the PNG format.  Some work, some don't.  Test first.

>As a rule, GIF files are the better choice for graphics composed of
>line art and fills of solid colors because a GIF file can contain only
>256 colors, as opposed to JPEGs that can contain millions or even
>billions.  You can obtain a smaller file with JPEG for this type of
>line art, but kilobyte for kilobyte, the GIF will look crisper and be
>free from artifacts ("ghosting") at the high-contrast edges.

So we thought, but in truth can see no difference at all in any of
our test cases so far...

>For photographic or fine-art material, JPEG is the better common
>choice since it does have a much broader color palette and therefore
>smoother transitions and gradients.  JPEGs created from TIFF files
>(Tagged Image File Format) tend to be the better choice for going
>to multiple platforms as opposed to those made from PICT (Apple)
>files.  I have no authoritative data on this, but have found it to be
>the case quite often, and surmise that it has to do with PICT being
>equally happy with both vector and rasterized graphics, which might
>put a header or preamble in the file that throws some filters off.
>(Mac users might already be aware of this when sending JPEG'd
>images to non-Mac users via email, depending on the mail client
>being used on the receiving end.  Convert to TIFF (IBM format),
>then to JPEG for more consistent results.)

Not sure about that one.  TIFF is another underspecified format, in
that it allows so many variant methods that *no* software can support
them all... so you have no way of knowing if your users can see them
as you do in advance.  PICT is definitely best just on Mac, like WMF
is for Windows, and for the same reason; both are simlpy a batch of
the graphic API calls on their respective systems (QuickDraw and GDI).
In contrast, JPEG really is cross-platform in nature.

>For technical manuals with plenty of line art, many of us are still
>waiting for PGML (Precision Graphics Markup Language) to make
>its web debut, since it allows the line art to be stored as vector
>art (much smaller than GIF or JPEG) that can then be scaled
>(zoomed) in the browser to yield PostScript-like detail at high
>magnification factors (which is what makes PDF much more
>desireable for things like interconnect diagrams or schematics).

I was quite startled to find that both Adobe and IBM had disclosures
on their submission of PGML for standardization that, if approved,
they reserved the right to charge any royalties they pleased!  This
is like GIF, but at least we know *in advance* that we can expect to
pay through some small orifice...  It does make me lose interest in
PGML; might as well just go for Flash, also a vector format, where 
the viewers are free (built into the new browsers) and the creation 
software is inexpensive.

>And that's my two (non-vintage) cents worth!

And worth every penny!  ;-)


-- Jeremy H. Griffith, at Omni Systems Inc.
  (jeremy@omsys.com)  http://www.omsys.com/

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