Ender100@aol.com
Date: 05/13/01-06:13:14 PM Z
Bob,
If you are scanning with an epson flatbed scanner, then the maximum OPTICAL
resolution of the scanner is probably 1200 ppi. If you are scanning above
the true optical resolution of the scanner, then you are really losing
quality since the scanner software is interpolating the image up from the
true optical resolution and you are wasting time and disk space. If, for
some reason you need a file that big you would be better off to let Photoshop
do the interpolation to the larger size and just store the original file, say
for example on cd's—cd's are cheap and so are cd burners.
Also, if you are scanning at above 8 bit depth, you can make all your
corrections to the scan and do your touchups and then store the final image
as an 8 bit file...this will cut the size in half. In your example of the
catalog cover, I'm guessing you were scanning a 16 bit file.... so halving
that would make it around 118 megs.... a large file still... but what would
you do with the image?
If the scans are for catalogs, then I would think that you would only need a
file of around 300 ppi, since most printing is done at 150 lpi (I think
printers usually want the file size in pixels per inch to be double the
lines per inch they will be printing at).
So you may not be needing to make your files that big.... I always scan at
the maximum OPTICAL resolution of my flatbed or my film scanner and save
that file and then downsample when I need to for whatever purpose, be it an
inkjet print, or a digital negative for an imagesetter. For the digital
negatives for an imagesetter I size the files at 600 ppi. However, if you
really want to save disk space, you determine the final size and ppi you
need for your target output and do the original scan that way.
One trick for saving money when sending images to a service bureau to have
digital negatives made is to check out their pricing structure and minimum
charge. You can usually save money by putting more than one image in the
same file in Photoshop.
Mark Nelson
In a message dated 5/13/01 6:11:37 PM, bmaxey1@juno.com writes:
<< However, I wondered how big of a file I would end up with at the
scanner's full resolution. I scanned a catalog cover, in black and white
and the file size was huge. At 1200 DPI, file size was 236.71 mb. At 7200
DPI it was 8.32 Gigs, and at full resolution of 9600 DPI it was over 14
Gigs. This was B/W - color was far, far worse.
So I will put this simple question out to everyone who wants to answer.
Please convince me about this, but if I want to work at the highest
possible resolution, for the best possible level of quality, What do I
do? I certainly can't scan the tens of thousands of color images I have
to scan for inclusion in a catalog at highest resolution.
Do the math - what kind of computer system do I purchase that will handle
a huge catalog of parts and literature containing even 500 images if
every image is at full resolution? >>
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