[Gimp-user] Large file size on TIFF to JPEG conversion

[DJ]

Hi gimpusers,

>> I am just astonished that I have to set such extreme quality values to
>> get a reasonable sized file.

> Very likely the TIFF files are 1 bit per pixel (only black or white,
> with no gray).  JPEG supports a minimum of 8 bits per pixel, so right
> away, with equivalently efficient compression, the JPEGs are going to be
> 8 times as large.

I think Ernie answered the question. But here's some additional
thoughts, that may or may not help solve the issue :-)

Wouldn't Image > Properties provide some additional numerical
information to concretely explain file sizes.


Some tidbits:

- Only save an image using a lossy compression once all other image
editing has been completed, since many image manipulations can amplify
compression artifacts.

- Ensure that image noise levels are as low as possible, since this
will produce dramatically smaller JPEG files.
http://www.cambridgeincolour.com/tutorials/imagetypes.htm

- JPEG Compression: The real story.
http://www.tawbaware.com/maxlyons/jpegcomp.htm

- Color data mode(Bits per pixel)
TIF
  RGB - 24 or 48 bits,
  Grayscale - 8 or 16 bits,
  Indexed color - 1 to 8 bits,
  Line Art (bilevel)- 1 bit

PNG
  RGB - 24 or 48 bits,
  Grayscale - 8 or 16 bits,
  Indexed color - 1 to 8 bits,
  Line Art (bilevel) - 1 bit

JPG
  RGB - 24 bits,
  Grayscale - 8 bits

GIF
  Indexed color - 1 to 8 bits
http://www.scantips.com/basics09.html

-- 
__________________________     
DJ