On Sun, Dec 03, 2006 at 08:52:31PM +0100, Alfio Puglisi wrote:
On 12/2/06, Lars Aronsson lars@aronsson.se wrote:
For example, the image http://runeberg.org/img/nfad/0670.4.png is 240 kbytes in 150 dpi 16-level grayscale PNG but only 200 kbytes in 600 dpi bitonal TIFF G4. The difference between 150 dpi grayscale and 600 dpi bitonal becomes very clear when you try to print the page on a 600 or 1200 dpi laser printer.
Well, you should compare apples to apples. The image you specified becames only 58 kbytes wen saved as 1-bit (bitonal) PNG. And bitmapped formats like PNG and TIFF have no concept of "dpi"- that's an external manipulation made by the printing program. You need to compare images with the same pixel sizes.
Well, an inference could be made that when one describes two images with differing DPI renderings that the *final size in inches* is expected to be the same, but you're right: that's expecting too much of the speakers... :-)
Cheers, -- jra