Re: Nikon D40 or Canon XT or ?

Matt Clara <none@xxxxxxxxxxxxx> wrote:

BMP and TIF are both lossless, and TIF also offers lossless compression.

TIFF also offers lossy compression, though not every TIFF
reading program will understand. :-)
As fas as I know, BMP is one of the few image formats in use that
could make use of compression but does not.

I've never felt a need for PNG.

Less complex than TIFF (do read the specs some day, it's amazing
how mindboggling complex a legal TIFF --- even if you only use the
basic 'must be supported' features --- can be made to be), does
transparency and it is free from patent encumberments (remember
GIF?). It's accepted by the W3C and supported in any halfway
modern webbrowser, and yes, it can save 16 bits per colour channel.
PNG is always streamable, unlike TIFF. It does checksumming.
It supports interlacing, so you can get a good idea of the image
even if only a small part of the data has been transmitted yet.

And it's of course vastly smaller than BMP and does a very good
lossless compression.

It's not the perfect image format, obviously. Lossy JPEG is
smaller for photographs. GIF is simpler and the compression
is nearly always the same, no matter what you do[1] and it does
animation[2], too. TIFF does CMYK.

-Wolfgang

[1] If you (as programmer) choose (or allow the user to choose)
inefficient options for compressing your image in PNG,
compression can be worse by a factor of 2 --- it is possible
to losslessy re-compress PNG files for minimal size, and
programs doing that exist.

[2] PNG "only" offers the practically identical MNG format.
.

Relevant Pages

  • Re: OT: Early Fall
    ... Since you are not processing the jpg and then saving the file, the compression and decompression will not introduce noise into the photo. ... TIFF pictures store a single raster image at any color depth. ... Not all TIFF files are compatible with all programs that support the baseline TIFF standard. ... JPEG pictures store a single raster image in 24-bit color. ...
    (rec.boats)
  • Re: Dissapearing Image
    ... This web site is a good source to understanding .tiff. ... Mary Sauer MSFT MVP ... the image color compression for images to lossless compression. ... and then click Microsoft Office Document Imaging. ...
    (microsoft.public.publisher)
  • Re: JPG or TIFF
    ... At true minimal compression a JPEG image has almost all of the original ... construction cunningly manages to discard high frequency noise ... or extreme dynamic range images where 12bit TIFF comes into its own. ...
    (rec.photo.digital)
  • Re: Is Tiff format lossless, no matter what Program you use?
    ... PhotoFiltre: No options whatsoever. ... "Save as...", select TIFF, set compression to JPEG. ...
    (rec.photo.digital)
  • PS to TIFFG4 shows compression artifacts at 600DPI
    ... currently using (Tiffany) converts the PS files into TIFF G4 ... compressed images with very good results - gradations are relatively ... and photos show no obvious compression ... TIFFs does not support LZW compression, ...
    (comp.lang.postscript)