I) just did some screen tests compressing jpeg's (from tiff). Until I compress to more than 6 (12 is min compression, 0 is max, I can't really se any difference on the computer screen! Prints may be different, though.
Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -----Oprindelig meddelelse----- Fra: Sam Jost [mailto:[EMAIL PROTECTED] Sendt: 13. november 2004 14:03 Til: [EMAIL PROTECTED] Emne: Re: Reducing File Size with Photoshop Yep, 3 for three bytes of color data for each pixel. I usually caculate in bytes, not bits. :) In the ancient times before jpeg every image was uncompressed and huge. In these ancient times hard discs had been much smaller and storage was expensive, so a bunch of smart people sat together and invented a storage format for images to get them a lot smaller without loosing too much image details -> jpeg For more information I'd suggest a look at theyr homepage http://www.jpeg.org/jpeg/index.html Sam ----- Original Message ----- From: "Jens Bladt" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 13, 2004 12:52 PM Subject: RE: Reducing File Size with Photoshop > Noooo... > It's 6 040 064 pixel * 24 (colour depth - in bits per pixel) = 144 961 536 > bits = 144 961 536/8 = 18 120 192 bytes = > 18.12 MB. > > I you meant 24 bits/8bits pr byte = 3 (explaining the "3" in your math) - > it's fine. > > I guess I don't understand what a jpeg compression really does! > But you are right - I saved a jpeg file as a tif and then it kept the 18MB > size, showing this in the Path Finder. > Jens Bladt > > mailto:[EMAIL PROTECTED] > http://hjem.get2net.dk/bladt > > > -----Oprindelig meddelelse----- > Fra: Sam Jost [mailto:[EMAIL PROTECTED] > Sendt: 13. november 2004 12:10 > Til: [EMAIL PROTECTED] > Emne: Re: Reducing File Size with Photoshop > > >> Can anyone explain: >> Why is the file size of an *ist D image say 3.936 MB in the Path Finder, >> and >> 17,3 MB when opened in PS? > > I'd guess 3.936MB is the file size, probably jpeg (compressed) > And 17.3 MB is the uncompressed image data for the image (3008x2008x3) > > Sam > >
