TECHNICAL PAPER

The Technology of Enhanced Saturation 100D color /5285

By David L. Long Downloaded at SMPTE Member on 2012-08-10 from IP

The technology behind the enhanced color reproduction of Kodak Here, the three primary compo- Ektachrome 100D color reversal film/5285 will be outlined. Attention will nents of visible light (red, green, and be given to both the chemical and photophysical design considerations blue) reflected from a scene are cap- incorporated into the technology, as well as some of the benefits offered to tured in the red, green, and blue-sen- its users. sitive layers of a silver halide photo- graphic film; this process is known as latent image generation. The latent odak Ektachrome 100D color Photographic Color image consists of small silver parti- Kreversal film/5285 was intro- Reproduction: The Basics cles formed within a silver halide duced to the motion picture market in Before any discussion of the color crystal as a consequence of the reac- December 1999. Its release marked enhancing technology incorporated tion of silver halide with visible the culmination of a number of years into 100D film can begin, some light. Once the film is developed of work on the part of researchers in background into the basics of color through appropriate processing both Kodak’s Color Reversal and rendition theory in photographic sys- chemistry, the red, green, and blue- Entertainment Imaging R&D groups. tems are presented, starting with the layer latent images are converted 67.247.176.132 The design concept was to create a very elementary representation of the chemically into subtractive photo- highly saturated color reversal film at photographic process in Fig. 1. This graphic dyes, cyan, magenta, and an EI100 speed without compromis- figure is designed generically to yellow, respectively. These three ing flesh and neutral reproductions. dyes are chosen because they are the

describe either a or positive @ SMPTE All Rights Reserved A total of three films incorporating image capture film, though more spectral complements (or opposites) the high color technology have been detailed differences between the two of the three primary additive light introduced by Kodak: Professional will be discussed later. . The term subtractive refers to Ektachrome film E100VS for the professional still mar- ket, Elite chrome extra color 100 Table 1—General Performance Attributes of the EKTACHROME 100D Film film for the consumer still photogra- phy market, and Ektachrome 100D Speed True EI100 color reversal film for the motion picture market. A summary of gener- Best-Fit 1.6-1.7 (positive sensitometry) compared to 1.8-1.9 for al performance attributes of the three a print from EXR 50D Film/5245 films can be found in Table 1. Table 2 shows the characteristic curve com- Sharpness Acutance higher than any EI100 speed reversal pro- parisons between positive duct and similar to AMT ratings of an EXR 50D print 100D film and camera negative Grain Comparable to other EI100 speed reversal products Eastman EXR 50D film/5245 printed and advantaged over the EXR 50D print by 4.5 grain to a positive on Kodak Vision color units print film/2383 (the only fair sensito- metric comparison of a negative film Reciprocity No filter corrections required for exposures from and a positive film requires the nega- 1/10,000 to 10 seconds tive be printed). Raw Stock Stability Comparable to any Kodak motion picture capture product This is an expanded version of a paper presented at the 142nd SMPTE Technical Conference (no. 142-30), in Pasadena, CA, October 18-21, 2000. David L. Long is Color High saturation of scene colors with accurate treatment with Eastman Kodak Co., Rochester, NY 14650. of neutrals and flesh tones Copyright © 2001 by SMPTE.

228 SMPTE Journal, April 2001 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285

square in the scene appears as a red Table 2—Characteristic Curve of EKTACHROME 100D film/5285 versus EXR square now on screen. 50D film/5245 printed on KODAK Vision /2383 In a positive film like 100D, the process is a bit more complicated. With no printing step involved, the red square must be imaged directly on the original piece of capture film as yellow and magenta dye, if it is to appear red when projected. In the reversal process, the red, green, and blue lights are still imaged in red, green, and blue-sensitive film layers; however, now instead of dye being

formed in the layer that was specifi- Downloaded at SMPTE Member on 2012-08-10 from IP cally exposed at image capture, dyes are formed in the layers that were not exposed. The secret lies in the processing chemistry. The first step in the rever- sal process takes the latent image sig- nal and turns it into a negative black- and-white image (with relative expo- sure yielding a proportional amount of “black” silver); no dye is produced in this step. With that image formed, a second stage creates latent image in the action of the dyes removing cer- ture film absorbs its complement (red the unexposed portions of the film tain spectral transmission from a light) from the white source leaving and turns this new image into colored white light source in order to modu- only green and blue light incident dyes via the same route already late color.1 upon the receiving film. These two described for color negative material.

In a negative-acting film, red light colors of light will produce magenta Consequently, any area of the film 67.247.176.132 captured in the red-sensitive layer of dye and yellow dye, respectively, in that was exposed to light has the the film will produce cyan dye; simi- the receiving film. black silver image but no dye, and larly, green light will induce magenta When this piece of film is project- any area that was not exposed to dye formation in the green-sensitive ed using a standard white light light has dye present (plus the afore- @ SMPTE All Rights Reserved layer, and blue light will induce yel- source, the magenta dye absorbs its mentioned elemental silver by-prod- low dye formation in the blue-sensi- complement, green, and the yellow uct). The final stage of the chemistry tive layer. A bleach step in the chem- dye absorbs its complement, blue, removes all of the silver and silver ical processing must also be included from the source. What halide from the film, leaving only to remove developed silver from the remains is only red light hitting the dye in those areas not exposed. film, because a by-product of the screen. As a result, what was a red In summary, the red square images dye-formation reaction is elemental silver at all of the latent image sites; a fix step completes the processing, removing unexposed silver halide from the film and stabilizing it against further . The subtractive complementary dyes in the capture negative are transferred or “printed” to a receiver piece of film, which is also negative acting. For example, imagine taking a picture of a red square. The red square is imaged in the red sensitive layer of the capture film and conse- quently cyan dye is formed in that layer. In printing, a white light is shone through the capture negative and onto a receiver film (the color print film). The cyan dye in the cap- Figure 1. A simple representation of image capture.

SMPTE Journal, April 2001 229 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285

tion, something that has definite color reproduction consequences in a film system. Once the spectrophotometry is measured, a set of calculations simi- lar to those outlined by Hunt adher- ing to the CIE1 standards will yield three color metrics: L*, a descriptor of a color’s luminance or “lightness” from black to white; a*, a measure of a color’s hue along a red-cyan axis; and b*, a measure of a color’s hue Figure 2. Typical spectral dye density curve for a photographic dye. along a yellow-blue axis. With these

three terms, any color stimulus Downloaded at SMPTE Member on 2012-08-10 from IP in the red layer of the film, but the piece of media. It is rather the theo- directly viewed by the eye can be reversal development process creates retically ideal space of colors that described in terms of its hue and its dye in only the unexposed green and can be represented by any mixture of lightness. The CIELAB color metrics blue layers (magenta and yellow the dyes. are designed to establish a measure- dye).2 To characterize the color of an ment of space that is approximately individual dye, its spectrophotometry linear in perceived color differences. Photographic Color or spectral dye density must be deter- In other words, any two scene colors Reproduction: The Details mined. This is simply a measure of a (or film dyes) mapped into the The two-stage picture of image dye’s ability to transmit light at each CIELAB coordinate system will formation described above is admit- of the wavelengths in the visible henceforth be represented by a calcu- tedly simplistic. The actual photo- spectrum. Figure 2 represents a typi- lable difference in psychophysically physics involved in rendering the cal set of spectral density curves for perceived color. total visible color palette are decid- a cyan dye. Though this example refers to dye edly more complicated. Still, the Each curve offers information on color characterizations, the CIELAB more in-depth details of color repro- how much light is absorbed by the calculations allow the measurement of duction may be understood within dye in each of the three principal the color of any visible object with a the context of the two simple steps regions of the white light spectrum specific spectrum. In order to calculate 67.247.176.132 above, exposure and dye formation. (blue at ~400 to 500 nm, green at CIELAB coordinates for a real color ~500 to 600 nm, and red at ~600 to patch in a scene, the illuminating The Impact of Image Dyes 700 nm). The three curves are also source spectral power output is cas- caded with the reflectivity of the scene As already mentioned, subtractive meant to represent the measurement @ SMPTE All Rights Reserved dyes are intended to modulate color at three different concentrations of patch to give the spectrum of light by controlling the transmission of dye; with more dye present, the den- incident upon the eye. This spectrum specific spectral regions of the visi- sity expectedly increases. It is impor- is integrated with the eye’s color- ble light scale. By considering the tant to note, however, that the matching functions (a mathematical spectral modulation characteristics of increases at each wavelength are not representation of the eye’s spectral each of the three dyes incorporated proportional; in other words, real sensitivity) and converted into percep- into a film (cyan, magenta, and yel- photographic dyes can change their tive color metrics, L*, a*, and b*. low), we can begin to derive the transmission profile (and hence their Returning to the discussion of pure range of colors that can be repro- color) depending on their concentra- photographic dyes, the CIELAB duced with these dyes, a concept known as color gamut.3 Color gamut calculations involve characterizing the specific spectral profile of each of the dyes in a film system and determining the colors that can be rendered with a given combination of those imaging species. The gamut of reproducible colors will include everything from the pure dyes, to combinations of only two of the three dyes, to various combinations of all three. The impor- tant point is that a dye system’s color gamut is measured independent of how the dyes come to exist on a Figure 3. CIELAB color gamut representation of a theoretical photographic dye set.

230 SMPTE Journal, April 2001 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285 color gamut for a dye set is estab- lished by calculating the L*a*b* locus for every possible combination of our dyes. The color gamut space is consequently three-dimensional, because three parameters are used to describe each color. Figure 3 shows one example of the way in which the CIELAB color gamut of a film can be represented. Even though CIELAB is a three-dimensional coor- dinate space, it is convenient to think Figure 5. Typical spectrophotometry of real photographic dyes vs. block dyes. of the color gamut in terms of the 2

two-dimensional plots shown. Downloaded at SMPTE Member on 2012-08-10 from IP In Fig. 3, the left plot shows three- dimensional color gamut projected onto the a* b* hue plane. Every color perceivable by the eye is represented by some position on this plot (with the center representing the neutral tone scale); the L* axis is shown per- pendicular to the page on this plot just for proper perspective. The area within the dotted lines is the hue gamut of the dye system. The diagram on the right in Fig. 3, shows color gamut from the perspec- tive of the third CIELAB dimension, L*. Here, the six primary hue direc- tions (red, green, blue, cyan, magen- ta, yellow) from the a* b* plot are Figure 6. Example of the CIELAB hue gamuts of real and block dyes. 67.247.176.132 chosen and a trace of L* versus C* is made (L*C* gamut). C* is a measure white). In between L*=0 and only green light, and yellow dye only of chroma or “colorfulness” and is L*=100, however, the C* plots form blue light.4 Figure 4 shows a spec- triangles as the hue colorfulness trum of ideal “block” dyes. Figure 5

exactly the linear difference between @ SMPTE All Rights Reserved the origin gray and the actual hue reaches some maximum at an inter- represents the spectrophotometry of a coordinates on the a* b* plot. This mediate lightness value. As stated real dye set complete with the char- makes sense as the colorfulness can earlier, the spectral dye density curve acteristic overlapping absorption pat- be thought of as the difference from shapes of real dyes will change as a terns versus the block dye set. gray for a specific lightness value.1 function of dye concentration. The Figure 6 compares the CIELAB The right plot, displays a charac- nonlinearities in each of the triangu- hue gamuts of block dyes and real teristic triangular gamut for L* ver- lar plots can be attributed to this dyes. Hunt has shown that a set of sus C* for each of the six primary change in “color” as a function of “block” dyes built with optimized hues. Any color at L*=0 goes to zero dye amount. spectral densities can produce clean- chroma, because the definition of A final point needs to be made on er eye responses than a set of real L*=0 is absolute black (a shade of image dye contributions to color dyes with overlapping absorptions. gray). The same argument explains reproduction. The subtractive photo- Because real dyes tend to modulate why all of these plots also converge graphic system has been described as light across broader spectral zones, to zero chroma at L*=100 (where the one where cyan dye is intended to they create color “cross-talk” through color is by definition a reference modulate only red light, magenta dye unwanted absorptions. As a result, colors rendered with real dyes appear less colorful than they might for block dyes and the gamut of repro- ducible chromas is reduced. Again, this conclusion is predicated on the block dyes being chosen as ideal with respect to interactions with the eye. To this point, the discussion has Figure 4. Sample spectra of three block photographic dyes. centered on the eye’s response to a

SMPTE Journal, April 2001 231 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285 color stimulus and the ducible within the film may actually dyes to the intended image dyes.6 calculations used to characterize that be smaller (as a consequence of color Not only are real image dyes not per- response. As such, the most accurate contamination) than the second film fectly cutting with respect to the color gamut calculations are intended with the inferior dye set.5 eyes, as explained earlier, but real for systems that are directly viewed Three photographic design fea- photographic products will not image by the eye (the capture film in a posi- tures describe the influence of the the single dyes anyway. In a positive tive system or the receiving print film exposure stage of the image chain on system, this comes into play as in a two-stage negative system). For a color reproduction: spectral sensitivi- unwanted image dyes can be pro- negative capture system, how the ty, sensitometry, and image-modify- duced as a consequence of scene receiving film “sees” the dyes in the ing chemistry.2 Spectral sensitivity exposure. In a negative system, the capture film must be described dictates the amount of exposure to be phenomenon here is actually seen specifically. In fact, the color gamut recorded by each of the three layers twice: first, when exposure to the that can be achieved with a piece of in a film as a function of the incident capture film causes unwanted dye receiving color print film is not an wavelength of light. formation (due to the capture film Downloaded at SMPTE Member on 2012-08-10 from IP entirely comprehensive measure of Ideally, the red-sensitive layer has spectral sensitivity); and second, the colors that can be reproduced its peak sensitivity in the red portion when exposure through the capture with that of print film. Rather, the of the spectrum; likewise the green- image dyes causes unwanted expo- color gamut of a two-stage negative sensitive layer is most sensitive to sure in the receiving film (because of system depends on both the dyes of green light and the blue-sensitive the relationship between the receiv- the receiving film and the dyes of the layer is most sensitive to blue light. ing film spectral sensitivity and the capture film; consequently, the clas- Though this peak requirement may capture film spectral dye densities). sic calculated receiving film gamut be well represented in real photo- The second exposure feature influ- must usually be adjusted, in practical graphic films, there is still some encing color rendition is sensitome- cases, to account for these influences. degree of overlapping sensitivity try (the amount of dye produced as a The principal conclusion to draw among layers at the spectral bound- function of incident exposure). As from this analysis is that dye spec- aries as illustrated in Fig. 7. spectral sensitivity dictates the trophotometry is one of the key The consequence of this overlap is punch-through exposure in a film, determinants of the color gamut that illustrated with an example: any sensitometry will dictate how much can be achieved with a typical photo- green light intended to expose only unwanted dye that exposure will gen- graphic film.1 Though the interac- the green layer of the film may, as a erate.2 tions of dye and eye are complicated function of specific spectral sensitiv- Image-modifying chemistry is the 67.247.176.132 in theory, comprehensive color space ities, actually expose the red and the last piece in the color reproduction calculations developed to date have blue layers also, producing unwanted puzzle. This feature, also designated allowed systems to be modeled and cyan and yellow dyes (a process interlayer interimage effects (IIE),

understood in terms of true perceived known as punch-through). For “pure” represents the sum of attempts made @ SMPTE All Rights Reserved color rendition. spectral colors imaged by a film, ren- by film designers to account for vari- dering multiple dyes will usually ous unwanted spectral absorptions of The Impact of Exposure reduce the chroma or colorfulness image dyes and unwanted punch- As mentioned previously, the compared to a single dye (imagine a through exposures recorded by multi- palette of colors that can be repro- yellow color represented by yellow layer films. If spectral sensitivities duced by a photographic product is a and magenta dyes rather than by yel- and dye inefficiencies contaminate function of both the image dyes low dye only). This should make fur- color reproduction, shrinking the incorporated into the film and the ther sense as it, in fact, takes approx- reproducible color palette, IIE is the photophysical features of the expos- imately equal amounts of all three mechanism available for attacking ing process within the film. It is cer- dyes in order to produce a true neu- the unwanted dyes and removing the tainly important to discuss color tral (defined as zero chroma). unwanted absorptions. gamut maps for film dye sets; how- Color contamination is a result of Figure 8 shows one use of IIE in a ever, the process by which light is the addition of the punch-through converted into those dyes must be acknowledged. It is quite conceivable that a comparison of two films will find one to have a truly superior dye set represented in a much broader color gamut map than the other. It is also conceivable that the same film may not be able to image those supe- rior dyes in a pure form and can therefore not fully utilize the advan- taged spectral dye densities. In this case, the color space truly repro- Figure 7. Typical spectral sensitivities of a .1

232 SMPTE Journal, April 2001 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285

reversal film. In this example, blue light has exposed the blue layer of a film as intended but has also exposed the green layer of a film, producing unwanted “black-and-white green- layer image” via punch-through. (It is especially important to clarify that this is a reversal film system: where “black-and-white image” is recorded, there is no dye formed; and where “black-and-white image” is not recorded, dye is formed.) To combat the punch-through

problem, chemistry has been added Downloaded at SMPTE Member on 2012-08-10 from IP to the blue layer such that when “black-and-white blue-layer image” is formed, an inhibitor molecule is Figure 8. Example of IIE in a multilayer film. released. That molecule can travel into the green layer and actually stop the reaction producing “black-and- white green-layer image” thereby preventing unwanted dye formation.2 This type of image modification approach can re-enlarge the color palette of a film, however, the tech- niques employed cannot solve all contamination problems. In a similar mechanism in negative capture films, IIE can be used to control unwanted negative dye formation (IIE is usual- ly not used as extensively in the sec- 67.247.176.132 ond-stage receiving films).

The Color Technology of 100D

Film @ SMPTE All Rights Reserved The basic concepts associated with photographic color reproduction have Figure 9. Layer structure of Ektachrome 100D film.7 been explained, and the technologies actually built into 100D color rever- sal film to effectively enlarge its color palette can be now addressed. Rather than concentrate on new image dye technologies, the scien- tists in the Kodak color reversal R&D labs determined there was more opportunity for enhancing color saturation in 100D film by manipu- lating exposure inefficiencies. New design techniques were incorporated to control the spectral sensitivity and interlayer interimage effects within the film. In Fig. 9, the control technologies are illustrated. The first layers to note are the Carey-Lee Silver blue-light absorber and solid particle filter dye green absorber placed above the green and red-sensi- Figure 10. CIELAB color (hue) palette comparison of 100D and E100S film. tive emulsion layers, respectively. By

SMPTE Journal, April 2001 233 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285 Downloaded at SMPTE Member on 2012-08-10 from IP

Figure 11. CIELAB color (hue) palette of100D/5285 vs. EXR 100T/5248 and EXR 50D/5245, each printed onto Kodak Vision color print film/2383. 67.247.176.132 carefully controlling the properties of ions are lost from the fine silver rifice overall color and tone repro- these two layers, the color reversal halide particles, halide is released duction accuracy. This said, the total design team was able to sufficiently into the film to act as an inhibitor in range of color saturation available eliminate unwanted absorption of other layers. with 100D film across the entire visi- blue light by the green and red layers The use of halide as an agent of ble spectrum has been found to be @ SMPTE All Rights Reserved and unwanted absorption of green IIE is classic; however, the mecha- larger than that for the classic motion light by the red layer, effectively nar- nism introducing inhibitor from the picture negative system (Fig. 11). rowing the spectral sensitivity bands new film layer is patented technolo- All of the color enhancements in for the respective layers (as com- gy.7 By modulating dye formation in 100D film are balanced carefully pared to negative films) and cleaning adjacent layers of the film, the new against proper neutral and flesh tone up punch-through concerns. color-amplifying layer affects the reproductions. A specific benefit is The real improvement in color amount of unwanted light absorption the ability to offer a high level of palette realized in 100D film, howev- present in specific rendered colors. color saturation at a true EI100 speed er, comes from the addition of a new The added bonus is that sharpness is while concurrently reproducing flesh layer to the top of the film structure. also greatly enhanced by the IIE and neutral tones quite accurately. This color-amplifying layer improves reaction (just as it would be in any All of these features combine to pro- color saturation by means of interlay- film incorporating this inhibitor-type vide the cinematographer with an er interimage effects and is the novel chemistry). excellent tool for capturing and technology employed in the film. A plot of 100D film’s color (hue) reproducing a new look in the motion This layer is comprised of a slow, palette is compared to the preceding picture market. spectrally sensitized emulsion Kodak reversal color technology together with a very fine coating of (Fig. 10). Practical picture testing Market Applications silver halide. Upon exposure and against properly exposed and printed The introduction of Ektachrome black-and-white chemical develop- motion picture negatives also shows 100D film has prompted a number of ment, this layer undergoes solution a color palette advantage for the questions about its motion picture physical development, a process by 100D film, though this must be quali- applications. As a positive original which the silver ions within the fine fied against the fact that a good color film, it is most easily used for emulsion are transported to the larger timer can often oversaturate specific telecine transfer of commercials and developing slow emulsion. As silver colors in a scene when willing to sac- television shows. Because the color

234 SMPTE Journal, April 2001 THE TECHNOLOGY OF ENHANCED COLOR SATURATION KODAK EKTACHROME 100D COLOR REVERSAL FILM/5285 enhancement technology in the film Endnotes realistic photographic applications. is centered on controlling unwanted 1. R.W.G. Hunt, The Reproduction of 6. Some spectral sensitivity overlap is dye formation, it will produce colors Colour, 5th ed., Fountain Press, England, not always detrimental. It is, in fact, quite that are more saturated not only to 1995. necessary for correctly reproducing some the eye, but also relative to a 2. T. H. James, Ed., The Theory of the difficult color transitions (teals, oranges, Photographic Process, 4th ed., MacMillan, etc.) and is used in conjunction with other telecine’s input spectral sensitivity. chemical manipulations to enhance hue Of course, within the telecine envi- New York, 1977. 1 3. Several techniques have been devel- accuracy in films. Still, when not properly ronment, color manipulation is a key checked, the consequence of this type of factor. Still, it would require some oped over the years to define human per- ceptive color space in terms of meaningful spectral punch-through will be a loss of time to take another film and produce metrics. As this paper is not intended to be apparent saturation in reproduced images. the colors that can be seen with 100D a tutorial on those measures and tech- 7. Keath Chen, “Reversal Photographic film right out of the camera (as well niques, the reader is encouraged to check Elements Comprising an Additional Layer as some likely increase in noise). the Hunt1 references for more details in Containing an Imaging Emulsion and a Downloaded at SMPTE Member on 2012-08-10 from IP A positive 100D film image can this area. With respect to our discussion Non-Imaging Emulsion,” U.S. Patent also be incorporated into feature pro- here, the color metric of choice will be the #5,932,401, 1999. ductions via the use of a digital inter- CIELAB color space (Commission mediate path wherein the images are International de l'Eclairage LAB). scanned, interpolated, and recorded 4. As it turns out, the eye’s spectral THE AUTHOR as a negative set of densities on color response to light is not as clear-cut as has been insinuated thus far. The three color- intermediate film. In this case, the sensing cones, which enable us to perceive integrity of the original captured pos- visible colors, do not absolutely differenti- itive can be maintained through the ate red, green, and blue light, but are rather systems and then output to a distribu- characterized by some degree of overlap- tion film. ping sensitivity (especially the red and Finally, the most exciting aspect green cones). Consequently, the eye’s defi- about reversal motion picture films is nition of red, green, and blue light is some- cross-processing. A set of unique what convoluted in spectral space. Rather looks can be achieved by sending than spend too much effort clarifying this images on 100D film through an point, it is sufficient to summarize that the

interaction of spectral dye densities and the 67.247.176.132 ECN-2 negative process. The impact spectral responses of the three cones of the on both tone scale and color repro- eye will dictate the dye system’s color duction place tremendous control in gamut. David Long joined Kodak in 1997 the hands of the cinematographer to 5. The concept of color palette is a as a member of the Manufacturing

achieve a look not available by other much better tool than color gamut for com- Research and Engineering @ SMPTE All Rights Reserved means. paring positive and negative systems. In Organization. In 1998, he moved the positive system, the image dyes incor- into his current role as product porated can be converted into a classic development engineer with the Conclusion CIELAB color gamut (independent of exposure effects), but negative film dyes Professional Motion Imaging Controlling unwanted dye forma- can only be defined in an “effective Division. His primary responsibili- tion through chemical interlayer gamut” dependent on the spectral sensitivi- ties include new product develop- interimage effects enables Kodak ty of the receiving film. As it contains a ment and image science and systems Ektachrome 100D film to reproduce dye set meant to be directly viewed, the integration for the motion picture the widest color palette of any 100 receiving film is eligible for classic product platform. speed reversal film, exceeding the CIELAB representation, but this would Long came to Kodak from the practical limits of the motion picture ignore the influence of the negative dye University of Texas at Austin where properties on the actual amount of receiv- negative system. Thus, 100D film he earned his B.S. in chemical engi- ing film dyes that can be produced in print- neering; he is also a graduate of offers cinematographers a new tool ing stages. In essence, the two-stage nega- for manipulating color, style, and tive system is the perfect example of how Kodak’s Image Science Career look in their finished products. exposure conditions can and will cause Development Program. color gamuts and color palettes to differ in

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