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PostPosted: Tue Nov 13, 2001 10:21 pm
by hhm
Sorry, please excuse me for the spelling mistake, Ian!
PostPosted: Thu Dec 27, 2001 5:01 am
by Doug_Robertson
Hi all,
Let me just say that 'hhm' seems to be the only one who has understood my point. Would the developers of Silverfast please read and think about this as I am sure there is some benefit in it.
I work as an engineer in a very computationally intensive field. Transform functions are commonplace, so I think I am onto something here. All we are dealing with is a series of transform functions.
If the scanner ICC profile function is scanf(x),
then a positive film scan image is:
image = scanf(raw positive data)
Scanning a negative, you cannot really apply the film profile until you are sure you have a correct representation of the color of the negative. Every scanner is different, but in the scanner profile you have a description that you can use to correct it.
If the film profile is filmf(x), then the correct approach is:
image = filmf( scanf(raw negative data))
It appears to me that the current implementation is:
image = filmf(raw negative data)
which will miss the scanner to scanner variations that are the whole point of scanner profiling.
Guys - I may be wrong, but if I'm right I think I should get a free copy of Silverfast for this idea! How about it? Silverfast 6.0 with IT8 calibration for positive *and* negative films!
Regards,
Doug
PostPosted: Wed Feb 20, 2002 12:21 pm
by eridon
Hi all,
I've got a message from support: Kristian Kratzenstein told me, that IT8 calibrates SF AI for transparency - positive and negative but you may execute it only with positives. That seems to bee true, cause the ICC in CMS is disabled in negative mode after IT8 in positive mode. This also seems to be wrong cause the auto-button doesn't change from gray to colored (for calibrated) in negative mode.<br>
I don't know whats right but I know that I spend mutch money on IT8 for no remarkable improvement using FUJI Superia 4th layer (see my topic) negative films.
Regards,
Stefan
PostPosted: Mon Jun 03, 2002 8:14 am
by LSI_Heidorn
@xander
>And make the adjustment of the film profiles easier.
Well, we tried hard to find a GUI for adjusting the profiles, if you have specific ideas how to make it more user friendly, please post it, we always long for feedback like that !
Nils Heidorn, LaserSoft Imaging AG
PostPosted: Sun Jul 07, 2002 1:06 pm
by Cedric Briscoe
This is a very helpful thread.
Nikon Coolscan 4000ed owners;
All this being said, what is the best thing (films) to scan with this scanner and SF 5.5.20 w/ IT8?
I had NO IDEA I was getting nothing for the purchase of the IT8 component. I brought this scanner as an alternative to scanning prints (Most of the time when people take pictures and have them developed they usually have the film, so to get the best you can, scan the film
I NOW wish to get my monies worth from SF and Nikon. So that I could create my own source, what is ?most ideal? to use?
(I assume I buy a camera, some type of film and what I scan originates from this source)
Thanks guys
IT-8 Calibration with negatives
PostPosted: Mon Sep 30, 2002 7:40 am
by Gregory C
I'm a Nikon 4000ED owner, and have had similar thoughts regarding calibration and Negafix. Like others, I too have noticed that the Negafix profiles in SF HDR are much better than in SF Ai NikonM !
So, why not pretend that the negatives are positives, use SF Ai NikonM and IT-8 Calibration to scan them, and then inverse/transform them using SF HDR and the HDR Negafix profiles?
If Lasersoft has limited resources with which to produce better Negafix profiles for every scanner type (profiles which by the way would not be 100% calibrated to *each* individual scanner), they should perhaps appropriate more of their resources to perfecting the HDR Negafix profiles instead.
Scanner + SF Ai NikonM + IT-8 Calibration
-> Calibrated negative images
-> SF HDR + Accurate Negafix profiles
-> Calibrated positive images
The only other thing that I would like to add, is that I would like to see SF write data to an EXIF resource (or another similar type resource) in the output file. The first thing I'd like to store there would be the film type of the original film in case I need to process the raw images again in the future.
regards
Gregory