I'm not at all sure I'm explaining myself well here.
Taking worst case scenario I'm scanning a 35mb neg to a 4000dpi tif file of
approx 110mb. Converting down to 8 bit halves the file size, changing either
pixel counts or DPI further decreases the file size and finally outputting
as a jpg can get to a final file for web use of around 100K. That is a very
large amount of compression and data is lost on the way.
Ignoring the way in which I compress (I've tried several processes) what has
become very clear is that the smaller the file I start with, the less
compression is applied, and the better results I get for the web - I
frequently find that heavily cropped scans are better for web output than
full frame and images from my C-3030 can often be very good indeed.
Obviously these smaller files do not print anywhere near as well as full
frame scans.
What I am wondering is will I get better web output files by scanning at
lower resolution and reducing compression. Has anybody tried this? Does it
work? And if so is there a way of approximating optimum scan resolution for
target display size?
While I'm going on about this.... Does anybody have a favourite film for
scanning, if so which?. I prefer colour neg and I think I've just fallen in
love with Kodak Portra 400 UC (but it is a horrid grey November in England)
Ian
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]On
Behalf Of Chris Barker
Sent: Saturday, November 15, 2003 1:59 PM
To: olympus@xxxxxxxxxxxxxxx
Subject: Re: [OM] Scanning / compressing a file for Tope 16
Ian
All you have to do is to reduce the size of the image to 600-700 pixels
long or high. Don't bother changing the resolution as it makes no
difference to the size of the file that results.
I scan at 4000 or 5400 ppi, save the resulting file for turther use,
normally as a .jp2 or compressed .tif. For web use I then reduce the
longest dimension to 750 pixels, save it as a .jpg (normally at 80-90%
quality, but aiming to keep the file size to less than 100Kb). I then
make sure that the file information is complete (using Photoshop
Elements) with my name, a caption and a copyright notation before
sharpening ever so slightly and saving it again.
The file is then ready for publishing. I am becoming more sensitive to
the Gamma setting of the destination monitors (since I have a Mac which
normally operates at 1.8), but that'[s about it.
Chris
On 14 Nov 2003, at 07:52, IanG wrote:
> I've managed to get an image that I'd like to submit for Tope 16 but I
> can't
> get the original scan to compress sufficiently and still produce a good
> screen display. Normally I scan to 4000dpi (Nikon 4000ED) and reduce
> this to
> 72dpi in several steps with a little unsharp at each stage. Mostly this
> works for an 'acceptable' result but sometimes (and in this case) the
> end
> result is too poor to use.
>
> Does anybody know of an idiots guide to scanning for screen output? I
> suspect I need to rescan at a lower initial resolution, maybe 1600dpi?
> Also
> I'm now using, and very impressed with, Kodak Portra 400 UC instead of
> my
> usual Fuji Superia 200.
>
> Thanks
> Ian
<|_:-)_|>
C M I Barker
Cambridgeshire, Great Britain.
ð
+44 (0)7092 251126
ftog at threeshoes.co.uk
http://www.threeshoes.co.uk
http://homepage.mac.com/zuiko
... a nascent photo library.
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