About .jpg

[Daniel Noelpp]

Hello Sandy

About the .jpg format you did an excellent job explaining it,
but I need to explain why .jpg "ignores" some information.

Sandy wrote:

> If you do use .jpg, you'll find that smudging creeps into the image if you
> edit it, because the .jpg format works by ignoring some of the information
> in the image - it loses a little information every time you change it. The
> ..gif format keeps all information, so your SignWriting will remain
> crystal clear no matter how many times you edit the image!

When storing a .jpg the colors in the picture are transformed
in a spectrum. This is a mathematical representation to make
compression easier. Now the funny part is that not the whole
spectrum is saved. You even can tell Photoshop or many
other software how much of the spectrum you want to save
(as a slider or as a percent value). The better quality you have,
the larger the file will be.

This is a very clever trick because the smudging is almost
inperceptible for photographic pictures. DVDs use a very
similar trick to encode movies.

So I hope you don't object to this small lesson even if the
subject doesn't relate to SignWriting directly. Sandy is right:
Don't use .jpg to save SignWriting texts!

Cheers!
Daniel