On 20 Aug 2003 at 20:25, [EMAIL PROTECTED] wrote:

> Hutcheson claims that "the transparent IT8 target has a lower D-max than 
> typical slide film. And hence the scanner profile made from that target 
> will fail to see very dark shadow details".
> What is your comment on that?

The claims made by Hutcheson about IT 8 targets are really just plain 
wrong and the IT 8 standard is pretty clear on the dmax (and other) 
field(s):

"The minimum transmittance factor that a photographic film can 
achive".

Now he claims to produce an targets with a bigger gamut/density range 
than IT 8 targets offer. But compare the reference files for the HCT 
targets with those of the cheap IT 8 targets sold on coloraid.de and 
you will see a different story ;-)  

> Also, could you provide links to the above publications?

I would recommend a nice book from Henry R Kang: "Color Technology 
for electronic imaging devices". Very easy to read and contains lot's 
of figures/test regarding scanner color correction. Definitly a 
starting point and the widely used  method in this book is pretty 
much on the level of various commercial tools :-( Lcms surely is much 
better ;-9  In this book you also find a table linking the number of 
patches used for calibration and the error limit achived. And from my 
exerience with my freeware scanner profiling software the figures 
given are correct in real-life. But you also find other papers on 
this issue from the sources below:

Many usefull info can be found on http://www.spie.org. They also 
publish the Kang books. Just use their nice search engine. For 
instance the "Color Imaging: Device Independent Color, Color Hard 
Copy and Graphics Arts" series has lot's of usefull info and they now 
offer the series and other usefull info on a relativly cheap single 
CDROM ;-) (hurts a bit after buying the much more expensive books... 
but CD does allow searching the articles.. so bought it twice :-) 
Being a SPIE member since years, I can really only recommend them to 
any developer and I am still surpised to often find commercial color 
software developers not knowing this (and other) organisation...

And I think there are some scanner profiling articles in the IEEE 
image processing journal... again, use their search engine... Also 
check IS&T... 

--
Wolf Faust                      Tel: +49-69-5486556
mailto:[EMAIL PROTECTED]         Fax: +49-69-95409598
http://www.coloraid.de          Mobile: +49-179-6924769



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