On 12-Feb-2004, "Douglas MacDonald" wrote:
"Tom Thackrey" wrote in message
On 12-Feb-2004, "Douglas MacDonald" wrote:
On looking at the help file, CS has an absolute limit of 300,000 x
300,000
pixels file size. This means a file size at 300 dpi of about 450 Gig!!
Must be windows problem.
300 dpi has nothing to do with file size. 300,000 x 300,000 x 3 = 270G
Not interested in this dpi verses pixels argument Tom. It’s purely a waste of breath.
Empty 16 bit file is over 500 gig. Put a few layers and images in it and it
will grow. Your file size is 8 bit, 72 dpi.
Interested or not, Douglas, the fact is you are wrong.
You can’t tell that ‘my’ file is 72dpi it could be any dpi. Do you see 72 in the calculation anywhere? bits per color, color chanels per pixel, pixel dimensions, layers, compression, and overhead all affect file size. The number of pixels per inch does not, its only role is to determine the dimensions of the image when printed.
The file I described is 8bits/color, 3 colors/pixel, 300Kx300K pixels, uncompressed, 1 layer. If you make it 16 bits/color the size doubles. If you convert it to CMYK (4 colors/pixel) the size increases by 1/3. If you change the pixel dimensions to 150Kx150K the size decreases by 3/4. If you change it to 1ppi or 1000ppi the file size remains exactly the same.
Pixels vs ppi (dpi) is analogous to miles vs mph, the number of miles between Seattle and San Francisco remains constant no matter how fast or slow you drive.
—
Tom Thackrey
www.creative-light.com
tom (at) creative (dash) light (dot) com
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