On 6/9/07, Moose <olymoose@xxxxxxxxx> wrote:
> To make a film profile, you take a shot of the printed IT8 target, then
> scan that and create the profile. You are looking for a map of colors on
> the film vs. the IT8 ideal. So the software, in my case, VueScan,
> compares the film scan to the known correct values for each patch and
> makes a list of the variations, which is what a profile is.
>
> An IT8 film target is for creating a scanner profile. I tried to get
> into those waters, but they seemed quite murky, although I do have one
> Ektachrome IT8 35mm target. What I read on the subject seemed to say
> that targets differ on different films, even though each slide comes
> with a calibration file. It all made no logical sense to me.
>
> It seemed to me that if you know the scanner's response to the whole
> range of defined colors on film, it should work for any film image, neg
> or positive. The way the IT8 target is defined, there is no negative
> version, I don't think. Any given color is that color, from a profiling
> point of view, whether its inverse is what will later be viewed or not.
>
> In my case, I gave up on scanner profiling, at least for now, and I
> cheat. My profiles are really for the combination of film and film
> scanner, as I couldn't figure out a proper way to profile the scanner.
> Works fine as long as I don't change scanners. I do think the scanner
> introduces much less variation than do the films.
>
> Moose
Based on some private email with Ed Hamrick that I had a while back,
it sounds to me as though you are doing it precisely the correct way.
He told me that scanner profiling is really only relevant for
transparencies. Since you are attempting to profile for color
negative, scanner profiling is not germane, at least as Vuescan is
intended to be used.
There are a couple things that bug me about Vuescan and the profiles
it builds and uses though. You still have to select the film
family/type and use it with the film you have profiled. This makes no
sense to me, since the film family/type is already a profile of a
sort. I complained about this to Ed and he agreed, though he didn't
promise to fix this in the next version. I'm not sure what he's
working on these days, but I doubt scanner and film profiling is high
on the list.
I also can't believe that little old me is the only one to have
thought of this, but by his response he seemed to indicate that I was.
Documentation/help is not as great as it might be. You have to kind
of wing it. I don't mean to complain about Ed Hamrick. Not everyone
receives every good gift. I think he knows his documentation is thin.
Nevertheless, profiling color negative film in Vuescan is a great way
to go. Highly recommended. I managed it using one of those 5x7
targets purchased from Adorama:
http://www.adorama.com/IKKIT857.html?searchinfo=it8%20target&item_no=3
Joel W.
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|