Ads, pt 6

pt 6 of 10

On Mon, 07 Feb 2011 06:52:28 -0600, Mitchell Holman wrote:

pt 6 of 10

While the posting of these images is very much appreciated,
the particular compression method for them is not to be
recommended.

These images have substantial amounts of text material
and JPEG compression, being based on the discrete cosine transform,
is not suitable for text. Notice the fine "halo" that exists
around each portion of text. This is an artifact of the DCT-based
compression.

For digital files that contain both images and text material,
PNG is the common compression method of choice. PNG will not
produce "halos" around text and the file sizes can be quite
close to that produced by JPEG compression.

Victor Diego wrote in newsan.2011.02.07.23.51.10
@live.com:

On Mon, 07 Feb 2011 06:52:28 -0600, Mitchell Holman wrote:

pt 6 of 10

While the posting of these images is very much appreciated,
the particular compression method for them is not to be
recommended.

These images have substantial amounts of text material
and JPEG compression, being based on the discrete cosine transform,
is not suitable for text. Notice the fine "halo" that exists
around each portion of text. This is an artifact of the DCT-based
compression.

For digital files that contain both images and text material,
PNG is the common compression method of choice. PNG will not
produce "halos" around text and the file sizes can be quite
close to that produced by JPEG compression.




Every time I have posted in a format other than
Jpeg I have gotten loads of complaints. And seen
the complaints at others for posting PAR and eYnc
and even Gif.

Jpeg is such a universal and easily read standard
it is hard to buck the system, however I will tinker
with PNG and see what develops.

On 02/09/2011 02:17 PM, Mitchell Holman wrote:


Every time I have posted in a format other than
Jpeg I have gotten loads of complaints. And seen
the complaints at others for posting PAR and eYnc
and even Gif.

Jpeg is such a universal and easily read standard
it is hard to buck the system, however I will tinker
with PNG and see what develops.


Unfortunately, also quite universal is an ignorance of basic
digital concepts. People are reluctant to accept anything
beyond JPEG because of a failure to understand. They literally
don't know what they are missing.

FWIW, here are two images of text material. One is compressed
with JPG and the other with PNG. Notice the very unsightly
"halos" around the text in the JPG version, whereas the
PNG version is quite clean with no artifacts.

On Wed, 09 Feb 2011 13:17:17 -0600, Mitchell Holman
wrote:

Victor Diego wrote in newsan.2011.02.07.23.51.10
:

On Mon, 07 Feb 2011 06:52:28 -0600, Mitchell Holman wrote:

pt 6 of 10

While the posting of these images is very much appreciated,
the particular compression method for them is not to be
recommended.

These images have substantial amounts of text material
and JPEG compression, being based on the discrete cosine transform,
is not suitable for text. Notice the fine "halo" that exists
around each portion of text. This is an artifact of the DCT-based
compression.

For digital files that contain both images and text material,
PNG is the common compression method of choice. PNG will not
produce "halos" around text and the file sizes can be quite
close to that produced by JPEG compression.




Every time I have posted in a format other than
Jpeg I have gotten loads of complaints. And seen
the complaints at others for posting PAR and eYnc
and even Gif.

Jpeg is such a universal and easily read standard
it is hard to buck the system, however I will tinker
with PNG and see what develops.

Also, unless your original material is in a format other than JPG (or
larger), converting to PNG won't really help. =(