DCML Digest, Vol 21, Issue 26 tiff format images

[Søren Krarup Olesen]

Wdposter at aol.com wrote:

> I rarely reply to messages on the list, but Timo, I think you are off
> base here.  Sure  conversations about scanning may be off topic, but
> helping another member by answering a question about scanning comics
> for the best image is not.

I happen to agree on this actually.

> A Tiff file is another image format, like Jpeg or bitmap.  Scanning
> and saving an image in tiff format results in a smaller file size
> than if you saved it as a jpg, adobe pdf or bitmap image.  (bitmap
> and pdf images are huge in file size)

Less agreement! :-) The TIFF format does *not* in general provide a
smaller file than e.g. JPG. TIFF itself (being rather outdated) comes in
two forms 1) compressed and 2) not compressed. And by compression I mean
as-if-it-was-zipped, data are not lost in any way, in contrast to JPG.
TIFFs type 2 are comparable to bitmaps (BMP) and are equally large.
There are three forms of images:

1) Original (scanned) bits are all saved compressed:
TIFF(1), GIF and best PNG.

2) Original (scanned) bits are all saved un-compressed:
BMP, ICO, TIFF(2).

3) (Scanned) bit patterns are modelled, so only "coefficients" of the
particular model needs to be saved. It corresponds exactly to the way
audio is transferred through cellulars:
JPG, yes currently there is only this of importance.

Moving pics ("movies") and audio can be divided into the same three
groups. For example WAV files belong to group 2, MP3 to group 3 etc
etc... Everything follows the same pattern: Good quality => large files,
relative bad quality => small files. There is no way around this.

Søren