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Topic: dynamic range and exposure latitude?
Replies: 4   Last Post: Mar 1, 2014 8:37 PM

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Dale

Posts: 219
Registered: 10/31/13
Re: dynamic range and exposure latitude?
Posted: Mar 1, 2014 7:17 AM
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On 03/01/2014 06:08 AM, Jeroen wrote:
> Hey Dale,
>
> You will be happy to learn that the movie and TV industries
> are collaborating on new standards for any or all of:
> - high dynamic range (luminance between 10^-4 and 10^4 nit)
> - wide color gamut (the entire visible spectrum, and more)
> - higher static resolution (4k x 2k, 8k x 4k), and
> - higher frame rates (60, 120, maybe 240 fps).


mpeg or ICC or ?


>
> About adapting images to a limited dynamic range or color
> gamut, that is a manual artistic process called "color
> grading". It is an illusion that this would be left to the
> built-in properties of a chemical or electronic system.


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


>
> The best that the industry can provide is a transparent
> standard for carrying the images to the viewers, the rest
> is still up to the creative people of "Hollywood".


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
http"//www.kodak.com

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.
http://motion.kodak.com/motion/index.htm
http://motion.kodak.com/motion/Products/Product_Information/index.htm

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
http://en.wikipedia.org/wiki/ProPhoto_RGB
http://www.color.org/search.xalter?q=rimm&go.x=0&go.y=0
http://www.color.org/search.xalter?q=erimm&go.x=0&go.y=0
http://www.color.org/search.xalter?q=romm&go.x=0&go.y=0

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
http://www.color.org

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
http:/www.color.org

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
crosstalk
http://en.wikipedia.org/wiki/Color_motion_picture_film

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
crosstalk

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
hands

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
http://www.makingkodakfilm.com/

>
> Many displays will have low dynamic range, narrow color
> gamut, low resolution or low frame rates. Maintaining
> compatibility with this legacy requires some form of
> remapping of the content to the target display gamut.
> If this is not sufficiently predictable then the creative
> community may decide to stick with the old standards,
> because then at least the result is entirely predictable.
>


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


> Best,
> -- J.
>
>



--
Dale



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