Beginner question on SilverFast CMS

[Doug_Robertson]

If I get SilverFast with the IT8 target (Nikon 4000ED scanner), how does the scanner profiling work with different kinds of film? I assume the custom scanner profile will be used for all transparency films, but what about negative films?

Thanks,
Doug

[ilyons]

On 2001-11-05 23:35, Doug_Robertson wrote:
If I get SilverFast with the IT8 target (Nikon 4000ED scanner), how does the scanner profiling work with different kinds of film? I assume the custom scanner profile will be used for all transparency films, but what about negative films?

Thanks,
Doug

IT8 is for postive film and is NOT compatiblle with negatives. Calibration isn't required or even desirable with negative type films. SilverFast will disable the scanner profile and uses film specific profiles for negatives.

Ian L

<font size=-1>[ This Message was edited by: ilyons on 2001-11-05 23:39 ]</font>

[Doug_Robertson]

Thanks for the reply, Ian.

Since I'm no imaging expert, I have the luxury of ignorance in thinking about this. So I wonder - why is it not desirable to use the IT8 calibration profile before the negative-film-type profile for best overall results? If the IT8 profile corrects for the characteristics of the specific scanner's color perception, then that should be applied *whatever* is being scanned. This would then provide a standard color image of the negative, independent of the specific scanner. For negative films, this corrected image would then be processed through the film-type ICC profile. It seems to me that this would produce the most consistent results across devices.

[ilyons]

On 2001-11-06 05:33, Doug_Robertson wrote:
Thanks for the reply, Ian.

Since I'm no imaging expert, I have the luxury of ignorance in thinking about this. So I wonder - why is it not desirable to use the IT8 calibration profile before the negative-film-type profile for best overall results? If the IT8 profile corrects for the characteristics of the specific scanner's color perception, then that should be applied *whatever* is being scanned. This would then provide a standard color image of the negative, independent of the specific scanner. For negative films, this corrected image would then be processed through the film-type ICC profile. It seems to me that this would produce the most consistent results across devices.

The orange mask . As soon as you apply the IT8 calibration profile to the negative you change the characteristics of the mask and so the film profile becomes junk! Film profiles are not ICC profiles. ICC have no specification for film profiles.

[Doug_Robertson]

Ian,

OK. I have to defer to you on this, although I still think I'm missing something. What I get from this is that you can profile your scanner all you want, but for negative films you'll be back at square one anyway.

Doug

PS - Ian you are a great asset to this board.

[xander]

Doug,

On the LS4000 the scanner profile is completly disabled while scanning negatives, not only because of the answers in the post above, but also because SF is disabling the negative to positive transformation, which is somewhere hardware based in the Nikonscanners, and changing it for the Negafix interface in SF5.5. This is not back to square one , its more like a hole in one (different ball game)Negafix will support you with all kinds of different profiles for different negative films, they will give you a perfect result(with some tweaking here and there) better then any scanning interface before.

Xander

[hhm]

Sorry Jan, sorry Xander,
I do not agree with your answers. I do not say, that your answers are completely wrong, but they are not really answers to Doug`s question/note. Doug never said, that Negafix would not be great. I myself think, that it?s the best for negatives we have today. But this does not mean, that there could not be improvements. From the mathematical point of view, Doug is right. Think of transformations (or functions) applied to an image in sequence. I try to write it in plain words.
For a positive you usually have:

Scanned_image = manual_adjustment(profile_correction(scanning_errors(image)))

If you do not make manual adjustments, you can omit it from the formula. Then if profile_correction is the inverse transformation of scanning_errors (this is archived by calibration), then:

Scanned_image = image

which is normally the desired result. For negatives it looks a little bit more complicated. For the moment we have (omitting the manual_adjustment):

Scanned_image = inversion(negafix(scanning_errors(orange_mask(inversion(image)))))

Ignoring the scanning_errors, negafix has to be the inverse transformation of orange_mask, which depends on the film. Silverfast does a great job in providing negafix for a lot of films. But this way it will never be perfect, because scanning_errors depend on the scanner and will rarely be the identity. Of course you can not calibrate the scanner with a negativ (I assume Jan, that you thought that Doug suggested this), but you could use the same profile you got calibrating your scanner with a positive target (and I think, that this was it, what Doug meant). Then the above formula changes to:

Scanned_image = inversion(negafix(profile_correction(scanning_errors(orange_mask(inversion(image))))))

Since profile_correction and scanning_errors are inverse one to the other, they will throw out and you get:

Scanned_image = inversion(negafix(orange_mask(inversion(image))))

This time without ignoring the scanning_errors.

I suppose that one reason why Silverfast does not implement it this way, might be, that the orange mask varies so much between even the same type of film, that even with negafix there will always remain a much bigger error, which you have to remove manually, than the errors introduced by the scanner. So eventually the additionally correction by calibration would not be worth the effort ? both in programming it and in the resulting additional computing time.

But I found one other interesting point in your note Xander:
You wrote, that Silverfast disables a hardware based negative to positive transformation when scanning negatives. Would there be a way, to disable it also on positives? It seems, that the scanner decides with some automatism when do apply this transformation. This causes some pain for me. (See my topic ?Blau- Cyanfarbstich beim Scannen??)

[ilyons]

<font size=-1>[ This Message was edited by: ilyons on 2001-11-12 23:40 ]</font>

[ilyons]

On 2001-11-12 23:27, ilyons wrote:
Hhm,

Of course you can not calibrate the scanner with a negativ (I assume Jan, that you thought that Doug suggested this), but you could use the same profile you got calibrating your scanner with a positive target (and I think, that this was it, what Doug meant). Then the above formula changes to:

Scanned_image = inversion(negafix(profile_correction(scanning_errors(orange_mask(inversion(image))))))

I'm called Ian that is an "I" NOT a "J". Where I come from Jan wears a "skirt"



Nope! The IT8 is based upon a positive. A negative film even without the mask has entirely different characteristics to a positive.



<font size=-1>[ This Message was edited by: ilyons on 2001-11-12 23:40 ]</font>

[ilyons]

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<font size=-1>[ This Message was edited by: ilyons on 2001-11-13 00:09 ]</font>

[ilyons]

<font size=-1>[ This Message was edited by: ilyons on 2001-11-13 00:09 ]</font>

[ianders1]

In order for what they want to work, to work, you'd have to do a custom profile for each negative film that you scan. It wouldn't be adequate to do profiles for each scanner model as each individual scanner has it's own unique characteristics, thus necessitating IT8 calibration for positives. Of course then, we'd have to account for developing problems, and provide reference files for each negative film.

So, NegaFix, plus the least possible amount of manual adjustments seems to be the best way to do it. I'm not saying that there aren't better ways, but not currently, and not within most of our budgets.

-Ian A.

PS. I also spell mine with an "I" and I don't wear a skirt!

[Guest]

positive film is 'WYSIWYG'<>(what u see is what u get), it's already a 'finished & final product' where as negative film needs inversion and profiles for different brands(fuji, kodak, agfa, konica are all different!).

film profile and channel is complete different from ICC, two worldly different things. different film manufacturers have all different profiles and also developing chemicals for their own films.

nikon scans are magneta reddish especially on slightly overexposed fuji film, i await patiently for further updates and refinements.

royal gold and max400(slight pink reddish cast) & mitsubitshi, konica after correction turns out just fine, u'll get great ichiban results from these films.

[ianders1]

I wasn't trying to say that the Negafix profiles and ICC profiles were the same, but they both have similar functions and serve to correct an image's colors. I merely meant that to achieve PERFECT negative film profiles, one would have to personally create profiles on their own scanner. I understand to people want profiles to be refined and as close to perfect as possible, I do too. With Negafix, I'm able to get very close to the correct colors, and using Silverfast's tools, I'm able to get the perfect image quickly and easily.

I agree with others on this forum, though - Slide Film is much, much easier to scan and with IT8 calibration, yields amazing results. I think that if you're serious about getting the best digital file to begin with, you should shoot with Fuji Provia or Velvia Professional Color Reversal.

-Ian A.

[xander]

For our Ian's don't worry if you are called Jan, in Holland/Germany/Belgium/Denmark they are not wearing skirts.
(the english name would be John!)

I agree with Ian about positive scanning, Velvia and Provia are perfect! Actually i find all the Fujichromes perfect!
One remark for my LS4000, if scanning positives, WITHOUT IT8, I use NONE for "scanner--internal", in the "Colour management", and NONE in "Scanner" in "Profiles for ICM". I find the results slightly better in Silverfast (not in Nikonscan!)

It would be welcome if the Negafix film profiles for Nikonscanners would be better, on the other hand Nikonscanners work differently like others, with LED's. Their transformation, the one Nikonscan is using is hardware based, and in no means perfect on many brands of film. Kodak for one seems to be without problem with Nikonscan, SF 5.2 and v**s**n. Fuji is hard to scan with these programs.

v**s**n is the only other program I know besides Negafix using film profiles, but its missing good Fuji support, Nikonscan doesn't scan Fuji very well, and the new Beta versions of 3.1 show no change! Are Nikon or Fuji sitting on information they are not so willing to share, or is this nonsense. (If I mention Fuji, I mean the latest dye's, not these from a few years back!)

Negafix seems to have cracked the nut for me, although I hope they will improve the Nikon support! And make the adjustment of the film profiles easier.

Xander