Fixing Snaps in a Snap

At 05:46 PM 06/20/2005 -0700, TidBITS Editors wrote:
> when you copy the picture onto your computer, convert it to a TIFF
> file and work on that.

Better yet, use PNG.

TIFF is infamous for compatibility problems. The issue is that whereas the
other types are image formats, TIFF is a file format. It's like saying
"send me the letter in a purple envelope to make sure I can read it" and
then the letter comes and sure enough it's in a purple envelope and I can't
read it because it's in Russian. By contrast, formats like JPEG and PNG are
like specifying the language the letter should be written in. TIFF has come
to be conventionally associated with uncompressed bitmap formats, but this
is not always so in practice.

PNG is a newer format than the others, and as recently as 2000 or so, one
had to be concerned about what software could read and write PNG. No longer
so; it's hard to find an application that doesn't handle PNG. And
compatibility seems to be flawless, since the format was carefully defined.
PNG uses some lossless compression, so files are slightly smaller than
uncompressed files, though in most cases not impressively smaller.

Or if you use Photoshop (CS or Elements), just leave it saved in the native
PSD format, which is lossless, albeit not portable to other software.

> 2. Outdoors, the difference in brightness between the darkest
> shadows and the brightest details exceeds 1,000,000:1. On a
> printed photograph the range available is hardly more than 100:1.
> Clearly, you want to use all of the range that the paper will
> allow. You want to set the tonal levels within the photo to run
> from dead black to pure white. This step requires moving two
> pointers.

True, but it needs to be emphasized that the qualifier "outdoors" is
important and even then it's not always true. Particular cases where it's
not true are photographs of some drawings and other art work, and other
scenes with low natural contrast. Pictures of faces can mostly use the
algorithm presented, but with other subjects it often results in
grotesquely overexaggerated contrast. As Maurer emphasizes, judge by how it
looks.

Edward
Art Works by Melynda Reid: http://paleo.org

On 6/23/05 08:36, "Edward Reid" <edwardpaleo.org> wrote:

> TIFF is infamous for compatibility problems. The issue is that whereas the
> other types are image formats, TIFF is a file format. It's like saying
> "send me the letter in a purple envelope to make sure I can read it" and
> then the letter comes and sure enough it's in a purple envelope and I can't
> read it because it's in Russian. By contrast, formats like JPEG and PNG are
> like specifying the language the letter should be written in. TIFF has come
> to be conventionally associated with uncompressed bitmap formats, but this
> is not always so in practice.

Last time I had to work with TIFF a lot, there were something like 26
variants...this was in 1996, so it's probably worse now.

--
John C. Welch Writer/Analyst
Bynkii.com Mac and other opinions
jwelchbynkii.com