The Technology of Enhanced Color Saturation - Society of Motion … · 2014-01-15 · History of...
28
The Technology of Enhanced Color Saturation The Technology of Enhanced Color Saturation KODAK EKTACHROME 100D Color Reversal Film/5285 David Long Eastman Kodak Company
Transcript of The Technology of Enhanced Color Saturation - Society of Motion … · 2014-01-15 · History of...
The Technology of EnhancedColor SaturationThe Technology of EnhancedColor Saturation
KODAK EKTACHROME 100DColor Reversal Film/5285
David LongEastman Kodak Company
History of 100D Film Color TechnologyHistory of 100D Film Color Technology
Initial Benefit Statement
l Research into customer needs identified the value in producing a high color saturation film capable of ‘alternate looks’ in commercial, television, and feature applications
Product Development
l Technology was developed by Color Reversal and Motion Imaging R&D teams for incorporation into a new reversal motion picture film
l Resulting color technology inventions were patented by Kodak
General Performance Well Balanced Against High Color TechnologyGeneral Performance Well Balanced Against High Color Technology
Speed True EI100
Best-Fit Gamma 1.6-1.7 (positive sensitometry) compared to 1.8-1.9 for EXR 50D Print
Sharpness Acutance higher than any EI100 speed reversal product and similar to AMT ratings of EXR 50D Print
Grain Comparable to other EI100 speed reversal products and advantaged over the EXR 50D Print by 4.5 grain units (N)
Reciprocity No filter corrections required for exposures from 1/10,000to 10 seconds
Raw Stock Stability Comparable to any Kodak motion picture capture product
Color High saturation of scene colors with accurate treatment of neutrals and flesh tones
Characteristic CurvesEKTACHROME 100D vs. EXR 50D onto VISION Color Print Film
0
0.5
1
1.5
2
2.5
3
3.5
4
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5
Relative Log Exposure
Neu
tral
Den
sity
EKT 100D - RedEKT 100D - GreenEKT 100D - BlueEXR 50D Printed - RedEXR 50D Printed - GreenEXR 50D Printed - Blue
EXR 50D Print:Gamma = 1.8-1.9
EKT 100D:Gamma = 1.6-1.7
Quick Review of Image CaptureQuick Review of Image Capture
Two general stages in color films:
RedRed, greengreen, and blueblue light from a scene is captured by a piece of film
Captured light is converted into subtractivedyes (generally cyancyan, magentamagenta, and yellowyellow)in processing chemistry
The saturation of reproduced colors is dependent upon factors in both stages - we willbegin our discussion with the dye formation stage and then return to the light capture stage
High Color TechnologyHigh Color Technology
l Review of techniques for influencing color saturation and accuracy in any film
l raw (ideal) color gamut dictated by pure image dye spectrophotometry (spectral dye density)
Pure Dye Color GamutPure Dye Color Gamut
• A pure dye’s ‘color’ is characterized by spectrophotometry (spectral dye density)• Density = -log10(Transmission)
400 (wavelength of light in nm) 700
den
sity
different lines representdifferent amounts of this dye
B: ~400-500nmG: ~500-600nmR: ~600-700nm
Pure Dye Color GamutSpectrophotometry is gathered for all possible combinations of dyes in a film and converted into perceptive visual color space (gamut) via standard CIE (Commission International de l’Eclairage) calculations
a* (cyan to red axis)
b* (
yello
wto
blu
eax
is)
L*
CIE calculates a 3D Color Gamut Space: L* a* b*
Hue Gamut:
‘Hue Gamut’ isa 2D projectiononto the a*b*plane
Pure Dye Color Gamut
C* (chroma or colorfulness)
L*
(lu
min
ance
)
0
100
red bluegreen
cyan magenta yellow
Spectrophotometry is gathered for all possible combinations of dyes in a film and converted into perceptive visual color space (gamut) via standard CIE (Commission International de l’Eclairage) calculations
L*C* Gamut:
C* = (a*2 + b*2)1/2
High Color TechnologyHigh Color Technology
l Review of techniques for influencing color saturation and accuracy in any film
l raw (ideal) color gamut dictated by pure image dye spectrophotometry (spectral dye density)
l cleaner-cutting image dyes (defined against the eye’s color matching functions) will yield more saturated color reproduction
Gamuts of Different DyesGamuts of Different Dyes
Ideal subtractive ‘block’ dye (no contamination absorption of light)
Real photographic dyes (some contamination absorptions of light versus block dyes)
λ
D yellow dyeabsorbs B only
λ
Dmagenta dyeabsorbs G only
λ
Dcyan dyeabsorbs R only
λ
D
Gamuts of Different Dyes
Color (hue) gamut consequences of contamination absorption
a* (cyan to red axis)
b*
(yel
low
to
blu
e ax
is) dashed: block
solid: real
L*
High Color TechnologyHigh Color Technology
l Review of techniques for influencing color saturation and accuracy in any film
l raw (ideal) color gamut dictated by pure image dye spectrophotometry (spectral dye density)
l cleaner-cutting image dyes (defined against the eye’s color matching functions) will yield more saturated color reproduction
l in addition to spectral dye density, practical multilayer film color gamut is influenced by spectral sensitivity, sensitometry,and image modifying chemistry
The Amount of Dye Created Due to Exposure: Spectral Sensitivity & Sensitometry
Multilayer Film:
BlueBlue--sensitive layer producessensitive layer producesyellow dyeyellow dyeGreenGreen--sensitive layer producessensitive layer producesmagenta dyemagenta dyeRedRed--sensitive layer producessensitive layer producescyan dyecyan dye
White Light
The Amount of Dye Created Due to Exposure: Spectral Sensitivity & SensitometryThe Amount of Dye Created Due to Exposure: Spectral Sensitivity & Sensitometry
• Spectral Sensitivity dictates the amount of exposure to be recorded by each of the three layers in a film as a function of the incident wavelength of light
λ
sens
itivi
ty
RGB
• Here, the sensitivities overlap - in other words, green light which is intended to only expose the green layer may in fact expose the blue and red layers also, producing unwanted image dyes (known as punch-through)
The Amount of Dye Created Due to Exposure: Spectral Sensitivity & SensitometryThe Amount of Dye Created Due to Exposure: Spectral Sensitivity & Sensitometry
• Sensitometry defines the amount of image dye (both wanted and unwanted) created for a given level of exposure
• Because of the overlap of sensitivities, it is virtually impossible to produce a single dye in a multilayer photographic film
• Consequently, not only are real image dyes not perfectly cutting with respect to our eyes, real photographic products will not image the single dyes anyway
Image Modifying ComponentsImage Modifying Components
• Image modifying components are used to combat both the imperfections in the dyes themselves and the unintended formation of punch-through density from spectral exposures
• Proprietary chemicals are incorporated such that the formation of dye in one image layer leads to the repression of dye formation in an adjacent layer (Interlayer Interimage Effects or IIE)
Image Modifying ComponentsImage Modifying Components
Reversal Multilayer Film:
BB
GG
RR
B LightB Light
Intended Exposure:Intended Exposure:Blue Light Blue Light ++ Blue Film Layer Blue Film Layer ==‘B&W Blue‘B&W Blue--layer Image’layer Image’ + + InhibitorInhibitor
Unintended Exposure:Unintended Exposure:Blue LightBlue Light + + Green Film LayerGreen Film Layer = = ‘B&W Green‘B&W Green--layer Image’layer Image’
BUT,BUT,Blue LightBlue Light + + Green Film LayerGreen Film Layer + Inhibitor+ Inhibitor= No ‘B&W Green= No ‘B&W Green--layer Image’layer Image’
*Note: This is reversal; where ‘B&W image’ is recorded, no dye is formed
High Color TechnologyHigh Color Technology
l Review of techniques for influencing color saturation and accuracy in any film
l raw (ideal) color gamut dictated by pure image dye spectrophotometry (spectral dye density)
l cleaner-cutting image dyes (defined against the eye’s color matching functions) will yield more saturated color reproduction
l in addition to spectral dye density, practical multilayer film color gamut influenced by spectral sensitivity, sensitometry, and image modifying chemistry
l desaturation is a product of unwanted light absorption at exposure, dye contamination, and/or dye spectral density failures
High Color TechnologyHigh Color Technology
l The color of EKTACHROME 100D
l color saturation advancements are realized not in the image dyes, but in the light capture and chemistry manipulation stages
l color manipulated by specially engineered light absorption layers
l color-amplifying layer added to the top of the multilayer film structure (cutting-edge emulsion technology)
Color-Amplifying LayerColor-Amplifying Layer
l smaller silver halide crystals activated by spectral exposure
l modifies development in adjacent color records through the process of solution physical development and ionic inhibition (IIE)
l amplifies color saturation by modulating the development of unwanted dyes
l added bonus is the concurrent boost to sharpness realized by the chemical adjacency effects
l Kodak patented technology (US 5,932,401)
EKTACHROME 100D StructureEKTACHROME 100D Structure
Color-amplifying layer
Blue-light absorber (Carey-Lee Silver)
Green-light absorber (Solid Particle Filter Dye)
Anti-halation layer (Gray silver)
Four component, blue light sensitiveT-Grain® emulsion layers (fast, fast, mid, slow)
Three component, green light sensitiveT-Grain emulsion layers (fast, mid, slow)
Three component, red light sensitiveT-Grain emulsion layers (fast, mid, slow)
F, FMS
FMS
FMS
High Color TechnologyHigh Color Technology
l Absorption layers designed for cleaner spectral sensitivity, less unwanted light absorption (punch-through), and more accurate color rendition
l Color-amplifying layer designed to enhance color saturation through IIE and the modulation of color contamination
l Both pieces optimized to ensure a balance between accurate hue reproduction in the flesh and neutrals and boosted color saturation in scene colors
New EKTACHROME 100D Color PaletteNew EKTACHROME 100D Color Palette
-100.00
-80.00
-60.00
-40.00
-20.00
0.00
20.00
40.00
60.00
80.00
100.00
-100.00 -80.00 -60.00 -40.00 -20.00 0.00 20.00 40.00 60.00 80.00 100.00
a*
b*
5248 onto 2383
5245 onto 2383
5285
Yellow
Magenta
Red
Blue
Cyan
Green
1 JND (Just NoticeableDifference) = VectorLength of ~1.0
Current ApplicationsCurrent Applications
l Telecine Transfers - primary usagel direct transfer of a high color, alternate look for commercials,
music videos, television, etc.l high contrast relative to negative origination films offers an
added ‘look’ factor in the telecine regime
l Features - also possiblel high color positive camera original images incorporated into
features through digital intermediate or internegativetechniques
l Cross-processingl yet another ‘look’ option available with reversal camera films
(marked by especially high contrast, high color images and unusual hue rendition)
SummarySummary
l Market need for a high color ‘alternate look’ film for commercials, music videos, etc.
l High color reversal technology developed and patented by Kodak
l Color boosted with use of enhanced absorber layers and new color-amplifying IIE layer
l EKTACHROME 100D Color Reversal Film made available December 1999
AcknowledgementsAcknowledgements
Eastman Kodak ContributorsEastman Kodak Contributorsll Tom MaierTom Maierll Mike Mike MurdochMurdochll Spencer Spencer PughPughll Kathy Kathy GisserGisserll Steve Steve PowellPowell
ReferencesReferences
l Hunt, R.W.G., “The Reproduction of Colour,” 5th ed., 1995, Fountain Press, England.
l James, T.H., Editor “The Theory of the Photographic Process,” 4th ed., 1977, MacMillan, New York.
l Chen, Keath, “Reversal Photographic Elements Comprising an Additional Layer Containing an Imaging Emulsion and a Non-Imaging Emulsion” US Patent # 5,932,401, Eastman Kodak Company 1999.
