ELECTROCOLOR TECHNIQUE STUDY TECHNICAL DISCUSSION

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A002600110009-4
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: December 9, 2002
• Sequence Number: 9
• Content Type: STUDY

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ELECTROCOLOR TECHNIQUE STUDY
TECHNICAL DISCUSSION
This study will determine the limitations and potential of the
electrocolor processing system through the following 13 major areas
of investigation.
A. Speed - The present low speed of the print material requires
high illumination and~or long exposure times for large magnifications.
Investigation of increasing the material speed by 5-10 times is included
in the subcontract effort. A decrease in processing time, as
described elsewhere in this paper, is also to be investigated.
B. Resolution - The true material resolution will be determined.
Tests will be conducted to determine the resolution threshold of the
material.
C. Latent Image Stability - The Electrocolor principle depends
to a great degree on the ability to control the latent image in the
zinc oxide layer. It is necessary to retain the latent image without
degradation between exposure and plating; however, after plating any
remaining latent image must be completely destroyed to prevent "image
carry--over" and the sensitivity restored in preparation for the
subsequent exposure. The purpose of this investigation is to determine
the degeneration of.the latent image after exposure as a function of
time. In addition, tests will be performed to determine to what degree
"image carry-over" exists between colors. This is a measure of the
efficiency of the hot water wash to destroy the proceding latent image.
This aspect of the Electrocolor principle must be thoroughly
investigated to provide a sound basis for any changes in design
concepts.
D. Reciprocity Characteristics - This investigation will deter-
mine the limits under which variations of exposure time and intensity
induce reciprocity failure. Reciprocal variations in exposure time
and intensity result in a constant time intensity product, but produce
variations in print density. In the tri-color printing method used
in the Electrocolor system, reciprocity failure in any of the three
colors results in a. color balance shift. If this condition exists,
color analysis systems must be designed to compensate for this error.
A test program will be conducted to determine the reciprocity character-
istics of the present system in the normal range of machine operation.
E. 'Color & Contrast Control - The limits of color control are
closely tied to the degree of reciprocity failure and the ability of
the negative analyzer and control system to correct this error.
Declass Review by
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Testing will be conducted on the material, independent of the analyzer,
to determine the color response to exposure variation. The results of
the test will be presented on tri-linear graphs which will compare the
actual to the optimum results.
One of the most striking advantages of the Electrocolor system
is the ability t:o vary the gamma of the three colors independently or
together to effect an overall contrast variation. Tests will be
conducted to determine the sensitometric effects of variations in
plating time and voltages. The results will be plotted as D Log E
curves so that the limitations of the system can be determined.
F. Spectral Characteristics of the Print Material, Dyes, and Top
Coating Materials - Non-conventional use of the Electrocolor system
indicates high potential in false color and multispectral sensing. As
a basis for future developments, a spectral analysis of the material,
filters, and dyes will be performed. Some problems have been recognized
in top coating techniques in which a degradation of the base white has
become objectionable. A spectrophotometric comparison of the material
before plating, after plating, and after top coating will show to what
degree this condition exists. All specimens will be analyzed on a
Beckman Spectrophotometer and the results presented as percent trans-
mission or reflection versus wave length.
A portion of the spectral evaluation will include Kodak Ektacolor
material for comparisons. This study will generate objective data
regarding the color gamut of the Ektacolor material and the Electrocolor
System with various top coating materials.
This color gamut will show the visual appearance of the various
combinations of the image forming dyes. Further, it will furnish the
range of colors it is possible to reproduce with a dye system. As
would be imagined, this type of color map for a dye system is very
sensitive to changes in the dyes, 'the sensitive material, the laminating
or glossing process, and anything that alters the color tone reproduction
and color fidelity of the system. Since it is sensitive in this manner,
it becomes very useful in presenting a unified picture of how any
changes made later in the color system affect the ability of the system
to reproduce colors. Moreover, the results will.be presented in terms
of the human visual system.
G. Exposure and Development (Plating) Techniques - the present
methods of exposure and plating have served adequately for the prototype
equipment. These techniques, however, are limiting and a study will be
conducted to determine the possibilities for the improvements in the
exposing and plating operations.
H. Negative Analyzer and Control System -
color negative analyzer, built for to use with the Electro-
color system, was designed for either spo or otal integration analysis.
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A series of tests will be made to determine the accuracy and the range
aver which this accuracy can be maintained in correcting off-color
negatives. A series of control negatives will be prepared in which
controlled errors are produced. The ability of the analyzer to correct
these errors will give an indication of its capabilities.
I. Improvement of Access Time - The Electrocolor. system provides
a finished color print in much shorter time than conventional color
processes. This gain, however, is confined to small quantity runs due
to the sequential requirements of the processor. A full cycle must be
completed for each print. Therefore, batch processing provides no
advantage because additional time is consumed in dye bucket movement,
wash and dry operations, and single sheet material handling.
This study will investigate these areas and determine if access
time can be significantly reduced to make quantity production feasible.
The plan is to investigate at least four types of exposure plating
techniques which have potential access time reduction. The four that
are now apparent are:
1. Sequential (mechanical modification of present system)
2. Concurrent Stage System
3. Traversing Mechanism
4. One-shot
(1) In the present machine, using the sequential exposure and
plating technique, a print can be made in approximately ~+ minutes.
The actual time required to expose, plate, wash, and dry a print
is approximately 60 seconds. An additional 3 minutes is consumed
in non-productive mechanical operations. An investigation will
be made to determine what mechanical modifications ~rould reduce
the access time.
(2) Concurrent Stage .System - Although the problems app~,ar to
limit the potential of this system, it is felt theta study should
be made of a design in which the print paper is moved from the
exposing plane to the development stage. By the use of dichroic
mirrors, the three spectrally separated images could be directed
to three pr}nting stages. The red, green, and blue exposures would
be made simultaneously on three separate sheets of material.
After plating,-the three prints would be advanced and registered
in-the next stage. After the third advance, full color prints
would be produced in approximately one-third the present time, or
every 80 seconds. Problem areas are registration, complex. mechanical
movements, and elaborate electronic control requirements.
(3) Traversing Mechanism- Present indications are that a very
rigid negative-print material relationship must be retained for
precise registration. This requires that the dye application and
plating operation be brought to the print material. If the exposures
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were made by a moving slit, the plating anodes could then closely
follow, utilizing a meniscus application of dye. Awash and dry
module could be attached to the exposure slit anode combination to
complete a single color cycle. Like units could be attached for
the other two colors and provide a finished print with a single
traverse. Exposure variations could be controlled by light
intensity, slit width, and traverse speed. Plating conditions
could be controlled by anode width, traverse speed, and plating
voltage. The advantages to be gained by this concept are:
a. Time consuming dye bucket, wash,. and air knife movements
can be eliminated.
b. During the traverse, exposure, plating, wash, and dry
operations for all three colors can take place simultaneously
at different points on the print. j
d. .
area.
Plating current requirements can be reduced; due to anode
1
M
hi
i
e.
f.
ac
ne s
ze can be reduced.
i
Easel can be designed for horizontal operat'on.
g.
Mechanical movements can be reduced.
(~+) One Shot-- This concept is probably the mot sophist~~cated
and the most difficult to accomplish. It is based pn the use of
an emulsion coating in which Zn0 grains are spectrally selective.
One-third of the grains are spectrally sensitized to red light,
one-third to green light, and one-third to blue light. Zne dye
bath is likewise composed of selective dye particles which, upon
the application of the plating current, will be plated to the
proper Zn0 grain. The advantage of this system would be:
a. A single white light exposure (permits dodging and burning).
b. A s~.ngle plating requirement.
c. Separate exposure and plating operations (exposure of
next print can be simultaneous with the processing of succeeding
print).
d. No registration problems,
e. No dark adaption (resensitization) problems.
f. Considerable reduction. of access time.
g. Less elaborate printing and processing equipment.
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J. Improvement of Information Content - The information content
of a color photograph is to a great degree dependent upon: 1) the
ability of the system to record shapes in fine det~~.il, and 2) the ability
of system to separate these areas by variation in hue, value, and chroma.
Representatives of the have suggested that higher
resolution material is possible with some loss in color fidelity. An
investigation will be conducted to determine the limits and limiting
factors for material resolution. Sample coatings designed for
maximum resolution will be purchases and tested.
As a part of this study, a human factors investigation will be
performed to give an indication of optimum dye combination to maximize
visual acuity in false color detection. Tllis human-oriented research
will be designed to function in accordance with the color gamuts
generated for the electrocolor dye system. It will involve the detection,
by human observers, of specified targets of known size, hue, and purity
against backgrounds of equal brightness but differing dye and~or purity.
This study, as presently envisaged, will not require a great deal
of initial calibration to generate absolute visual data. The program
does depend upon the generation of the color gamut for the Electrocolor
system and its output should augment the color gamut program by stating,
in terms of human factors, how the Electrocolor dye system may best
be improved.
A study of various input materials, both color and black and white,
is necessary to provide a basis for correlation of the information
content of the negative materials and the ability of the printing system
to reproduce. The value of information gain through the use of color
material over black and white is rapidly becoming recognized. Further
potential exists in the use of exaggerated and false color techniques.
The Electrocolor systems has many advantages as a tool in investigating
these areas. There are no inherent limitations, as in conventional
multi-layer color materials, regarding a Mixed spectral sensitivity dye
layer relationship. A red record black and white separation negative,
for instance, can be projected with white light on the Electrocolor
material and plated with any of the three dyes. With the variations
possible in the choices of spectral band records and in the choice of
contrast to which these black and white separations can be processed,
coupled with the choice of dye combinations available; a tremendous
variation of information output is possible. It is even conceivable
that spectral bands outside the visible spectrum can be
translated into the visible spectrum and provide a co or isplay of
variations in energy at specific wavelengths. The potentials in this
area are not fully know, and the degree to which this information is
usable is yet to be determined. An investigation into the potentials
of the electrophotographic system to extend the information content
coupled with a human factors analysis of the usability of the information
will be undertaken..
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K. Larger Format - The present print material is limited to an
&2" X 11" format. Increased format sizes up to 16" X 20" will be
investigated. This study will closely coincide with the study and
tests for improving plating-current techniques. (item G)
L. Development of Reversal and Transparency Printing Potential -
The ultimate color photographic reproduction system would include the
capability to produce color prints or transparencies from color negatives
or positives. This study will investigate the use of electroplating
techniques, in reversal printing, to produce transparent print material.
M. Results of Study - The final report for this program will
include all possible improvements on the Electrocolor system supported
by laboratory models to validate the finds of the program. The report
will also include a~detailed outline for construction of a breadboard
model of optomized electrophotographic equipment.
The fabrication of a breadboard model and then of a prototype
machine with improved speed, resolution, production rate, print size,
and product flexibility is considered future work and is not included
in this program.
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