Al
Scanner profiling can be most worthwile so you ar edefinitely on the
road to an easier life. A good profile can deal with those
inconsistencies imposed upon evey scan by non linear scanners. Got a
magenta quartertone and green threequartertone in every scan you have
to remove manually? Wish you had a Photoshop ace at hand to correct
those anomalies almost instantaneously - that's what a great scanner
profile can do. A bad scanne rproifle can ruin what started out as a
nice image.
Soem fall into the trap of imagining that a scanner proifle will fix
bad images, with bad images - as with good ones, what tyou'll see after
assigning the scanner profile is a good rendition of the original.
Inaccuracies intact.
22/7/03 2:16 pm Alfred Loeb <aloeb-at-rochester.rr.com> wrote
>Using VueScan 7.6.52, I have calibrated my FS4000 scanner with a Kodak IT8
>target and data file as the user manual directs and produced an .icc file.
>If I then scan in the IT8 target, produce a .tif file and open it in
>Photoshop my eyedropper readings of the LAB values do not agree with the
>data in the IT8 data file for my target. Should they agree?
Well, firstly, you probably have a batch measured IT8 target, so the
data file is unlikley to agree exactly with the target in the first
place.
You're in the US - right? My friend Don Hutcheson who lives in new
Jersey can fix you up with his <<small batch measured>> 135 target if
that's what you want. Best to order from friendly distributor
www.Chromix.com who offers a small discount.
35mm Fuji Velvia Target : $149.00
That said and taking the target data as accurate (which with an
individually measured target it would be) - I guess that,
theoretically, the Lab numbers of capture and datafile should match.
But, since we are dealing with 16.7 million possible colours in any
image - and a fairly small profile matrix, they will probably not agree
exactly - even with the best SW. The input profiling SW manufacturers
have some hard work to do in working with smoothness and weighting
accuracy of calculation toward the more important tones and shades,
whilst dealing with gamut and hue angles accurately (or at least
working out the trade offfs between them).
I'd think that what's built into Vuescan must be fairly rudimentary at
the price (which is not to say it's not useful in some aplications).
You can get a good application from colour solutions - basICColor scan,
at an amazingly low price. I can even sell that to you if you like. Or
Chromix can.
If you buy the excellent <Real World Color Management> book and some
headache pills, you'll read of various (and somewhat complex) methods to
test profile accuracy but also note that the authors point out that the
most accurate profile is not always the most pleasing.
Do the scans look good to you? If so you've won.
Regards, NeilB. Apple Solutions Expert
colourmanagement.net :: Consulting in Imaging & Colour Management
custom scanner and printer profiles, training on Imacon Scanning
supply Gretag + eyeOne, ColorSoloutions basICColor : Display etc. XRite
www.colourmanagement.net/ :: www.apple.com/uk/creative/neilbarstow/
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