Re: Scanning Photos

[steam4me@enternet.com.au (Yuri J Sos/Melbourne)]

On 23 Jun 1999 08:30:31 GMT, markbau1@aol.comQQQQyuk (MarkBau1) wrote,
and I selectively quote:

>Your statement "Scan the pictures at whatever resolution you like because, the
>display will always show as the monitors PPI" shows you need to learn about
>this subject a bit. A monitor will only display a maximum of 96 ppi, (most
>monitors 72) so you tell me what is acheived by putting a 150 ppi pic on the
>web, except that it takes more space to store on the server (which for most
>people means more $$$ or less pics) and more time to download. 
>
>To repeat, there is no need to post a pic with a higher ppi than 96 (actually
>72 is the web standard) and anyone who knows what they are doing shouldn't have
>a file size much bigger than 100K unless they want their pic to be many times
>the size of most peoples monitors.

We'll change the name of this ng to aus.rail.scanners.basics <g!>

You obviously use a Mac, Mark, because every Mac user seems mired in
or fixated with 72 dpi/spi.  

One scans at whatever resolution one needs to end up with say an 640 x
480 pixel image:  the original's size will determine the scanning
resolution.  For example, a 5½" x 4" print scanned at 120 spi will
necessarily result in an image of ca. 640x480pixels.  Scanning that
same print at 72 spi will yield an image only ca. 400x290 pixels.
Scanning an A4 page (11.7x8.3 in) for that same 640x480 pixel monitor
means you need to scan at about 54 spi.

In the PC world, there are 12", 15", 17", 19" monitors.  Depending on
the video card and software driver *any* of these monitors are capable
of displaying 640x480, 800x600 or 1024x756 pixels.  It's the video
card and software driver that more frequently determine the monitor
size in pixels, which may not be related to the monitor size in cm or
inches.

>I'm sick to death of waiting for 500K jpegs to download on people's webpages
>that don't know what they are doing when the same quality could be acheived in
>say a 100K jpeg if the person knew a bit about this subject.

I totally agree:  a 640x480pixel image is 900k as an uncompressed
.TIFF or .BMP file.  I use Compupic 4.6 to create JPEGs at the 80%
quality level and achieve between 90 and 120k sized images for my web
pages.  Having viewed many of your photos, we both end up somewhere in
the same ballpark even though we take obviously different routes to
get there.

Actually, I find that it's a lot of commercial/business sites that
have 1600x1200 pixel images (as you say, 500k even with a JPEG) and
use HTML code to fit it into a 640x480 pixel sized display image,
forcing you to DL the 500k file then wait for NS or IE to resize it
for display on the screen.  The have ISDN/T1 lines and never realise
most people still surf at 28 or 33.6k.

       
Regards

Yuri
-- 
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Yuri J Sos
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