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Thread: Color seperation filter used in Drum Scanners

  1. #31

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    Re: Color seperation filter used in Drum Scanners

    Quote Originally Posted by Drew Wiley View Post
    Some of my best results are actually from Portra internegs from masked chrome films - bagging certain subtle hues I haven't seen cooperate in any photographic print medium so far. But Velvia dyes matched to Portra dyes and then RA4 - Nope.
    No doubt your very skilled, and like other contributors, that is a resource that prompts me to ask questions.

    It might be worth considering, while portra is suitable for making internegs from chromes it not suitable for internegatives/positive from original camera negatives, even if you fix the problem with the gamma or at least it is not optimal.

    Anyway, perhaps I should just get on and do some more work.

  2. #32
    A.K.A Lucky Bloke ;-)
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    Re: Color seperation filter used in Drum Scanners

    I must be way drunk (or blind). I canít remember anything in the c41/ra4 space close to a well developed kodachrome/e-6 when it comes to color accuracy.


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  3. #33

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    Re: Color seperation filter used in Drum Scanners

    Quote Originally Posted by onnect17 View Post
    I must be way drunk (or blind). I can’t remember anything in the c41/ra4 space close to a well developed kodachrome/e-6 when it comes to color accuracy.


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    Kodachrome has significant (but pleasing to some) colour inaccuracies - colour neg will always give more accurate colour & negative/ positive processes have a range of significant advantages over reversal ones.

  4. #34
    Resident Heretic Bruce Watson's Avatar
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    Re: Color seperation filter used in Drum Scanners

    Quote Originally Posted by interneg View Post
    ...colour neg will always give more accurate colour & negative/ positive processes have a range of significant advantages over reversal ones.
    Yes. This. Color accuracy is what that orange color correction mask is all about.

    One of those other advantages is of greater dynamic range captures. Said another way, color negative films can record a scene with more stops between the black and white points than can a tranny film. Indeed, modern color negative films come close to the dynamic range capture of B&W negative films.

    Bruce Watson

  5. #35
    A.K.A Lucky Bloke ;-)
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    Re: Color seperation filter used in Drum Scanners

    Wider dynamic range I agree but I feel E6 registers blues cleaner than C-41, IMHO.


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  6. #36
    Drew Wiley
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    Re: Color seperation filter used in Drum Scanners

    More misleading stereotypes, as if color neg films were all the same, or all chrome films were. It depends on the specific hues you're trying to reproduce, and via what medium. For example, I have an old print hanging around the corner made from old Ektachrome 64, which was capable of wonderful blue nuances and blueish sage colors, but due to red contamination of the green-sensitive dye, was incapable of producing a bright saturated yellowish "spring green" unless you jumped through a lot of hoops like masking the separation neg for a dye transfer print with around a 25% exposure to remove that bias. On the other hand, fairly early on, Fujichrome 50 was noted for vivid clean greens, but had a hard time with greens which were in fact kinda muddy to begin with. I've printed old pre-E6 Agfachromes that captured certain earthtones like no other film I've encountered since, and even certain fluorescent lichen colors; but the green repro was mute, almost like it had been deliberately skewed for a Godfather movie. Kodachrome was no silver bullet either, but bagged certain kinds of colors and neutrals in its own wonderful way, which I miss. But that didn't help much, because it was already long extinct in sheet film when I began. I shot a lot of Kodachrome 25 as a kid, and made a few nice little Cibachromes - a wonderful marriage of media; but "little" pretty much summarizes it. But rather than whimpering about all these limitations, there is an aspect to limitation itself which can be cultivated in an intelligent way to produce stunning prints from all these various films and print options. That require appreciating those limitations and not pretending you've got a silver bullet. For quite a number of years I exploited the idiosyncrasies of Cibachrome - no, not loud reds! It was a very idiosyncratic but potential beautiful medium. The significant limitations of C41 films have never particularly appealed to me in my personal work, though I used them for at least some of my occasional portrait work. There are other practitioners of muddy color negs like Meyerowitz who have built entire careers of eloquent work based on the repro shortcomings of good ole Vericolor L. I find Ektar far more appropriate to my own needs; but it too has some significant quirks. I don't know when I'm going to get around to printing up a few sets of black-and-white separation negs onto Fuji RA4 paper; but the negs are already made, and I already have all the necessary pin registration system. It's like having too many flavors to choose from at the local ice cream shop, with all being potentially rewarding if you're patient.

  7. #37

    Re: Color seperation filter used in Drum Scanners

    Most drum scanners = CMYK separation workflow
    Isomet = RGB 'photographic' workflow

    Sorry not enough time to discuss more..

  8. #38

    Re: Color seperation filter used in Drum Scanners

    Could you expound?
    Quote Originally Posted by calebarchie View Post
    Most drum scanners = CMYK separation workflow
    Isomet = RGB 'photographic' workflow

    Sorry not enough time to discuss more..

  9. #39

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    Re: Color seperation filter used in Drum Scanners

    Quote Originally Posted by Sasquatchian View Post
    Could you expound?
    I didn't write that post but I am the OP. I took what Calebarchie was saying is that most drum scanners used a "densitometric" approach rather than "colormetric" approach. I.e. for the former measure the amount of CMY dyes in the camera original (transparency) so that you can then reproduce that with CMY dyes on a piece of paper. You could argue that the later colormetric approach is a folly since you are limited to the CMY dyes used in your final print. The spectral response of a drum scanner is much closer to these CMY values, it in no way matches the spectral response of the human eye. Think status-a measurements.

    Contrast that with a modern digital camera, where the sensor still doesn't actually match the human eye response (to expensive). Where a matrix is used to give some sort of correct colormetric values, and then in "photoshop" various matrix's are used to vary the output to match your monitor and finally the print.

    I am not sure where Isomet drum scanners fit in this timeline exactly though.

    I have perhaps oversimplified things but this may convey the gist of it.

    This what partly prompted my original post.

  10. #40

    Re: Color seperation filter used in Drum Scanners

    Well, I know that there are three color filters after the splitter and before the PMT's, so my guess is that the ultimate gamut of the scanner is defined by those filters. I had a long conversation with John Pannazo about that twenty years ago but to no logical conclusion. And then, if you use something like Hutcheson Velvia scanner target to profile your scanner, that effectively limits it to the gamut of that film, which is going to still be quite a bit larger than any printing material you can find today. The specific target and especially the software used for the profile seem to have a pretty big influence on how that is all interpreted. The bottom line is that if your scanner can record pretty much everything that is one your film, that's about is good as it's going to get.

    While it's true that DSLR's have a much wider initial gamut seemingly than the PMT's of a drum scanner as defined by the sep filters, in the end, all that extra gamut may be useful in capturing saturated colors in the real world, but is largely wasted when using the same camera to make a single shot scan from color film. And you still have to decide how you want to get from wide open color gamut to something you can actually use. When I compare the gamut plots of my 5DSR to my Howtek 8000 in ColorThink 3.0, the Canon eclipses the Howtek by far but both provide exemplary results.

    I haven't spoken with Evan for a while so maybe I'll give him a shout out or just make that an excuse to drive to Orange County and hang out with him and pick his brain on the subject. Maybe in the fall.

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