dynamic range and exposure latitude?

Discussion in 'Darkroom Developing and Printing' started by Dale, Feb 27, 2014.

  1. Dale

    Dale Guest

    I don't have access to current professional equipment, software, or
    media, so I will rely on feedback and past experience, and the criticism

    video sensor and filtration device color space assumptions face a
    complexity with other output than CRT (LCD, LED, Plasma, OLED, and I
    read better LCD is on the way)

    ICC solution to dynamic range is based on ProPhoto RGB according to
    wikipedia (there is also Adobe RGB, and Wide Gamut RGB, on wikipedia)
    implemented in RIMM,ERIMM, and ROMM

    ICC does not reveal the assumed film or idealistic/standard film used in
    ProPhoto RGB

    ProPhotoRGB chromaticity coordinates are linear with CIE chromaticity

    CIE tone is linear with light (L,Y,B,V) or linear with lightness (L*)

    film due to chemical considerations of activity and exhaustion and
    design for dynamic range treatments, has a toe and shoulder modeled and
    designed using a quadratic as opposed to linear contrast, such as a
    rational quadratic which does not bend over the toe or shoulder

    since film contrast is not linear, some calculations must be performed
    to have it linear

    ICC does not reveal such considerations

    Kodak designed ProPhoto RGB, probably in light of sRGB workflows being
    accepted, as opposed to using an ideal digital camera and an ideal
    digital projector as the RIMM,ERIMM, ROMM (additive color used in
    displays has more dynamic range than subtractive colors used prints)

    one Kodak implementation I know called Premier (a system of scanning
    film, manipulating and editing film, and outputting film) used a
    linearized film assumption

    I believe this linearization was achieved by unbuilding the rationall
    quadratic contrast, and some form of interimage of an Ektachrome film of
    the time, be it spectral sensitivity interimage or chemical process
    interimage, I don't really know which one or if both were used, I heard
    it once but I forget

    some use cases would prefer color matching as opposed to appearance
    matching and would not use RIMM,ERIMM, ROMM, they would use CIE RGB

    but most use cases involve a viewing and acceptance of an image, even if
    it just a consumer looking at something and saying it is "good enough"

    what is ProPhotoRGB? Is it a negative with exposure latitude suiting it
    to ERIMM? if so this could complement many hybrid workflows where
    transparency film output is used or copied in an analog fashion

    in fact you could design a color negative film to be scanned,
    manipulated, output, and projected with ICC color management

    you unbuild the non-linearity and crosstalk of the film as long as it's
    image dyes chromaticity coordinates result in something close enough to
    linear with CIE chromaticity coordinates, making it easier to scan on a
    scanner whose exposure, filtration and sensitivity are designed to be
    linear with CIE chromaticity coordinates

    manipulation algorithms relative to CIE are widely available, but you
    could add analog editing, and hybrid algorithms to the mix

    you can design a projector (exposure, filtration) in a digital
    environment, with the right analog and hybrid manipulation
    consideration, to display a color negative instead of using a
    transparency intermediate

    such a projector design leads to an easy film recorder design

    same with monitor design ...

    is film dead? should you snip most of the above? are professional
    digital capture, manipulation and output already exceeding color
    negatives for dynamic range and exposure latitude? even considering push
    and pull chemical processing?

    then why not a digital RIMM,ERIMM and ROMM?

    the ICC site says color managed workflows have not taken hold in
    digital, I read once, is this because of sRGB(video) and
    ProPhotoRGB(film) workflow interference?

    are digital RIMM,ERIMM and ROMM to far outside of CIE eye based
    considerations? then why not use CIE RGB for the RIMM,ERIMM, and ROMM

    probably the best bet considering printed page is not dead and
    Perceptual Reference Medium (PRM) can be used in ICC
    is to give customers choices for their use cases of what reference suits

    things like lighting, surround, flare, viewing angle, measurement
    considerations likewise could all be incorporated

    a little more education,, maybe too much for "good enough" color,
    especially since "more attractive color" exists

    some form of device independent "accurate" color and appearance must be
    a starting point?

    for consumers, white balance might not be the only scene balance that is
    used, you could use analog and hybrid models to get to the "more
    attractive color" achieved in consumer films like "pop" saturation

    if you think I am a troll, give me a entry level imaging systems job in
    my area and I will have to keep my ideas to myself, I don't quite
    qualify for standards or open systems work, so here I am on usenet,
    wikipedia, wiktionary and the web

    I have an undergrad honors degree in ChemE with minors in polymer
    science and math (forget most of this)
    I know a little MATLAB and SAS
    I know basic programming on punch cards and punch card readers
    I know Fortran data flow programming
    I know modular Pascal data flow programming
    I know a little C
    I know a little object oriented (OO) architecture/design
    I know a little C++ OO programming
    I know the basics of java systems and OO programming
    I just can't get abstract IDEs like netbeans or operating system
    required libraries, out of my head to write a complex program
    maybe I should spend more time learning java than talking on usenet
    Dale, Feb 27, 2014
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  2. Dale

    isw Guest

    I did some film recorder development about 30 years ago. I don't think
    "easy" is a term I'd use in conjunction with their design (assuming you
    wanted any sort of decent quality, anyhow).

    isw, Feb 27, 2014
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  3. Dale

    Dale Guest

    sort of like applying "printing density" if you know what that is, maybe
    this will explain
    Dale, Feb 27, 2014
  4. Dale

    Dale Guest

    9 years on the job imaging R&D at Kodak
    17 years reflection and internet/wikipedia, etc. study
    Dale, Feb 27, 2014
  5. Dale

    Dale Guest

    I'm just talking to myself while I write and share my thoughts,
    sometimes I'm wrong, I even have two kook awards on alt.usenet.kooks
    from my political, philosophical, psychological,, sociological and
    religious viewpoints on other groups, feel free to nominate me for
    another kook award, I am not a troll, I am a kook

    never did any hardware development,

    I did paper development, process development, hybrid systems development

    no research assignments, an engineer not a scientist, but I dabbled in
    science when I could

    I'd like to think my mainly applications work that could have led up to
    system work at Kodak R&D for 9 years contributed to a little system
    development, or so I was complemented sometimes

    I had a good boss that told me to specialize and not try to understand
    everything about imaging, there are few generals in imaging standards,
    people like David McDowell

    you really have to read into my rudimentary explanations, somethings are
    outright wrong no doubt, just putting some pieces together in 17 years
    of reflection and internet
    Dale, Feb 27, 2014
  6. Dale

    Dale Guest

    and Software as a Service (SaaS) Cloud Computing

    java requires a license to distribute development, so C or C++ on my
    linux system is where I will look at metafile (vector/raster
    combinations) imaging stuff I think

    a specialization, better suited to me than trying to be a general of the
    whole imaging industry with my limited experience
    Dale, Feb 27, 2014
  7. Dale

    Dale Guest

    mpeg or ICC or ?

    if film workflows exist long enough, I thinkk you could design a hbrid
    system with ONE film, ONE chemical process, and a scanner, writer, and
    projector best suited to such film

    I think the film could be negative,, higher exposure latitude, but you
    would have to have a scanner, writer, projector designed for that film,
    this does mean approvals/edits would have to be viewing "soft" display
    or display(output) approvals

    a digital projector could receive the right codes values from the right
    ICC color management system

    after talking about hybrid systems for awhile here I decided to visit
    Kodak's website and see what analog and hybrid products they had

    looks like consumer is only digital I think
    no sight of the portrait market I think
    commercial products are all digital I think

    but there is a huge catalog of motion picture film, chemistry, filters, etc.

    they claim video clips highlights, there is no "toe" in digital
    contrast, and small gamut sRGB doesn't help, I see dress white shirts
    clipped on my CRT television

    they don't mention spectral reflectances, wide gamut RIMM, ERIMM, ROMM,
    like ProPhoto RGB don't even capture all of the eye's colors, let alone
    the clipping of a surface color when wide spectral reflectances hit it,
    this was a consideration with CCD scanning when I worked at Kodak R&D 17
    years ago

    are people still using film for quality?
    does film still have a dynamic range and exposure latitude advantage?
    (film contrast is not linear like gamma, it has a toe and shoulder due
    to chemical activity and exhaustion and optimization thereof, that
    curves off highlights and shadows leaving them reproducible

    do people still prefer the "look and feel" of some films like B&W?
    these "looks and feels" could be put into abstract ICC profiles with the
    right film characteristic information

    the right film characterization information is not even provided in the
    standardization of ProPhoto RGB as ICC's RIMM,ERIMM, and ROMM

    with the right film characterization information, one could develop a
    hybrid ICC system to suit Kodak's motion picture catalog, if there is
    time before digital capture, manipulation and projection replace the
    industry's establishment investment

    such a hybrid system, and the abstract ICC profiles mentioned above,
    could reduce Kodak's catalog to ONE input/output film and ONE chemistry,
    if such film was co-optimized with the right hybrid scanning,
    manipulation, and output

    if film still has a dynamic range and exposure latitude advantage,
    perhaps as it's standardization as RIMM, ERIMM, and ROMM, a color
    negative could be scanned, output and projected with the right ICC
    processing using film and equipment characterization information

    a film program cost around $5million when I was at Kodak.
    I have no idea how much or fast an equipment program would take

    but at least Kodak should share their film characterization information
    for optimization in existing information, use in existing digital
    manipulation and incorporation in abstract ICC profiles, this would
    allow more quality for the film, unless somehow you say they are
    operating on a price only paradigm

    included below is a list of some necessary film characterization
    information, an expert could add to or correct this list

    both empirical (easy way) and mechanistic (hard way) are supported
    mathematically by the ICC, but you could do your own system

    empirical characterization entails printing an equipment code value
    target to the "calibrated" equipment and relating it mathematically as a
    profile to the color of the profile connection space, usually cubic, a
    three dimensional profile for 3 colorant mediums, I know there are at
    least or there once was 4 colorant mediums from Fuji, I'll allow you to
    derive this from my post yourself, it is not hard if you know it

    even B&W colorants like silver halides have a hue that must be either
    maintained or translated in the ICC profile like a three colorant
    system, the eye is a three colorant system, I will allow you to derive
    B&W yourself, it is not hard if you know it

    with the advent of RIMM, ERIMM, and ROMM in ICC you can use digital
    manipulation for hybrid systems (you can search for these on the ICC
    site and they are from ProPhoto RGB according to wikipedia)

    so why would you want to do it the hard way, mechanistically?

    1) want to retain analog manipulation methods
    2) want to have analog manipulation algorithms within digital
    3) want to an analog capture of scene colorimetry
    4) multi-stage analog/hybrid systems do not calibrate
    (steady-state calibration is a prerequisite for profile characterization)
    5) want to design new analog equipment or manipulation
    6) want to design new sensitized media for a hybrid system
    ( a film program was around 5 million at Kodak 17 years ago)
    7) want to design a better analog RIMM, ERIMM or ROMM

    so how to do it the hard way?

    first, you will need a lot of information, the preferred way of getting
    this method is from analog media, equipment and software companies, as
    opposed to the investment yourself, some analog technology really
    requires single layer coatings to resolve crosstalk from spectral
    sensitivity and chemical processing, chemical processing can be just the
    way it is, process variability across or inside labs, or by design with
    things like DIR or DIAR couplers intended to reduce or optimize chemical

    Kodak has licensed some hybrid or analog technology to IMAX, the analog
    industry may be willing to deal at this point, additionally some analog
    and hybrid information may be patented, when I was at Kodak R&D many
    things were not patented due to other nations not respecting
    intellectual property, PhotoCD was patented as a last ditch effort to
    leverage capture film into digital systems

    so what type of information will you need?

    spectral sensitivity of capture mediums
    (for some systems digital capture sensitivity needs resolved to sensor
    and filtration)
    spectrophotometry of print (subtractive) output mediums
    (spectral data might have to be resolved to light source and filtration)
    spectroradiometry of display (additive) output mediums
    spectroradiometry of analog and hybrid printers
    (for some systems such radiometry of equipment needs resolved to light
    source and filtration)
    chemical colorant response to light of medium (DlogE)
    interimage, overall crosstalk of medium
    single layer coatings of mediums to resolve chemical versus sensitivity

    what are the use cases?
    1) captures (digital, hybrid or analog)(scene or like printing density)
    2) manipulations (digital, hybrid or analog)
    3) outputs (digital, hybrid or analog)

    spectral information is a one dimensional look-up table without crosstalk
    crosstalks are at least a linear matrix
    DlogE is best represented with a rational quadratic, higher math effects
    the central linearity, complete linearity effects toe and shoulder,
    highlight and shadow detail where dynamic range is low, this is still a
    one dimensional look-up table
    digital contrast is linear, gamma
    hybrid input/output contrast is calibrated for gamma in most cases
    multi-stage systems typically use some standard assumptions, mostly what
    equipment/software/measurement the systems engineer is working with

    any mathematician can take it from here to get all use cases

    if you want me to do a use case, just reply, I have a lot of time on my

    by the way, there is a book about "making" Kodak film, but not
    "designing" it, maybe the author might want to add a understandable
    compilation of this to his book
    if you allowed people their choice of RIMM, ERIMM, ROMM, PRM(G) or some
    appearance that is standard to their use case you could solve this

    the "looks and feels" of variety of film, filters, etc. could be put
    into ICC abstract profiles, like they put such edits into such profiles
    Dale, Mar 1, 2014
  8. Dale

    Jeroen Guest


    SMPTE, MPEG, BDA, ITU, ...
    Not likely, the future is digital and digital intermediate.
    HDR digital cameras already exist. It's the displays that
    are the problem. Or, more often, the lamp power.
    Yes yes. Accuracy in Digital Cinema is of prime importance.
    This is all typical of low dynamic range TV.
    Trust me that things are about to change in a big way.
    Not likely to happen. Digital is so much more flexible.
    But the experience of the Kodak experts is always appreciated.
    Information is one thing, understanding how to use it is
    another thing. And then to keep it simple...
    You are making that clear. ;-)
    Today's problem are of a different nature: how to best combine
    legacy with future needs. To build a standard that can span
    decades. And how to reduce the traditional television artefacts
    due to trying to do too much with too few bits.
    Sounds good. Maybe you can give some thought on how a DCI P3
    color gamut carried in a BT.2020 wide color gamut can be
    automatically mapped back into a BT.709 (sRGB) color gamut ?
    There will be a lot of need for that, because most UHD ("4k")
    standards will be based on BT.2020 color primaries.

    -- J
    Jeroen, Mar 1, 2014
  9. Dale

    Dale Guest

    you can do it two ways, mechanistic (hard way), empirical (easy way)

    there is a problem of "repurposing" a smaller gamut back into a larger
    gamut, best to keep the original with profile information then just
    "purpose" it again
    Dale, Mar 2, 2014
  10. Dale

    Dale Guest

    brings up a storage/portability issue, easily solved with ICC

    keep a copy of the image in a device independent space with appropriate
    RIMM, ERIMM,, ROMM applied like the profile connection space and then
    "purpose" it again instead of "repurposing" a file in an ouput device space

    you could also keep your edits on the file as ICC abstract profiles
    along with the device independent file,, or just keep the edited file in
    the working space

    mapping gamut can be done the hard way (mechanistic) or the easy way

    the easy way is too print a wide variety of machine code values to the
    output devices, measure the color or spectral characteristics, and then
    choose whether to convert it colorimetrically, absolute colorimetrically
    or maintaing saturation (perceptual mapping involves PRM(G) which is a
    print space, smaller than display/projection/editing for film or digital

    ideally you create a gamut conversions to the profile connection space,
    so they are device independent and can be "purposed" instead of "repurposed"

    I don't recall the mathematics of gamut mapping, I wasn't that
    experienced, but a three dimensional look up table could be used with
    linear or high power polynomials
    Dale, Mar 2, 2014
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