Optics: measuring and testing – By shade or color
Reexamination Certificate
2001-11-19
2004-05-11
Evans, F. L. (Department: 2877)
Optics: measuring and testing
By shade or color
C356S319000
Reexamination Certificate
active
06734972
ABSTRACT:
BACKGROUND OF INVENTION
This disclosure relates generally to color formulation and more particularly to generating a color formula for a color standard that satisfies predetermined requirements for withstanding exposure to a variety of weathering conditions.
In the plastics industry, plastic manufacturers generally use an accelerated weathering test to define and measure weathering properties of plastics. An accelerated weathering test typically involves the use of a weatherometer, which is an apparatus that exposes materials to artificial and accelerated weathering tests that simulate natural weathering conditions. In particular, the weatherometer uses controlled cycles of ultraviolet radiation, light, salt, electric arcs, water spray and heating elements to simulate the natural conditions of sun, rain and temperature changes. When a plastic manufacturer receives a request to produce a color standard of a plastic material from a customer, the manufacturer has to determine whether it can create a formula that produces the color of the standard such that the formula results in a color that satisfies predetermined accelerated weathering test requirements. Each formula comprises the pigments and dyes (collectively called colorants) that make up the color and the concentration of each of the colorants. Generally, in this scenario, there are a number of colorants that the manufacturer may choose from to produce a color. However, there are only a limited amount of colorants that the manufacturer may use that can satisfy accelerated weathering test requirements because many of the colorants are unstable and break down when exposed to a variety of weathering conditions. Since there are only limited amount of colorants that are stable when exposed to a variety of weathering conditions, the manufacturer relies on the experienced-based knowledge of its technicians to decide whether they can create a formula that can produce the color using only stable colorants. If the technician can produce the color standard from only stable colorants, then the manufacturer produces plaques or samples from the formula of colorants and subjects them to an accelerated weathering test. If the plaques pass the accelerated weathering test then the manufacturer will submit them to the customer for approval; otherwise, the manufacturer will repeat this process for another possible formula and continue until accelerated weathering test requirements are satisfied.
A problem with the above-described process is that the color formulation of deriving a color formula, producing plaques, applying an accelerated weathering test and waiting for approval from a customer takes anywhere from one to two weeks. From a customer's point of view, one to two weeks is too long to wait to hear whether the manufacturer can formulate a color match. Ideally, the customer would like to know within several hours whether the manufacturer can formulate a color match. Therefore, there is a need to expedite the formulation such that lengthy steps like the accelerated weathering test are removed or compressed from the process.
SUMMARY OF INVENTION
In one embodiment of this disclosure, there is a method and computer readable medium that stores instructions for instructing a computer system, to predict the color of a color standard exposed to weathering conditions. This embodiment comprises determining the concentration of the colorants of the color standard; obtaining weathered optical parameters for the color standard; and predicting the color of the color standard from the concentration and weathered optical parameters.
In a second embodiment of this disclosure, there is a method, system and computer readable medium that stores instructions for instructing a computer system, to predict the shift in color of a color standard upon exposure to weathering conditions. This embodiment comprises, measuring the color of the color standard; determining a color formula that matches the color standard; obtaining weathered optical parameters corresponding to the colorants and concentration of colorants used in the color formula; applying a light scatter model to the weathered optical parameters and colorant concentrations to determine the weathered color for color standard; and predicting the shift in color of the color standard upon exposure to weathering conditions from the weathered color.
In another embodiment, there is a method and computer readable medium that stores instructions for instructing a computer system, to determine a color formula that matches a color of a color standard and satisfies accelerated weathering test requirements. This embodiment comprises receiving a sample of the color standard; measuring the color of the color standard; and determining a color formula that produces the measured color and satisfies accelerated weathering test requirements.
In a fourth embodiment, there is a method and computer readable medium that stores instructions for instructing a computer system, to predict the shift in color of a color standard upon exposure to weathering conditions. This embodiment comprises, inputting a color measurement of the color standard; determining a color formula that matches the color standard; obtaining weathered optical parameters corresponding to the colorants and concentration of colorants used in the color formula; applying a light scatter model to the weathered optical parameters and colorant concentrations to determine the weathered color for the color standard; and predicting the shift in color of the color standard upon exposure to weathering conditions from the weathered color.
In still another embodiment, there is a system for determining a color formula that matches a color of a color standard and satisfies accelerated weathering test requirements. In this embodiment, a spectrophotometer measures the color of the color standard. A color database contains a plurality of colorants and optical parameters and weathered optical parameters associated with each of the colorants. A computing unit, coupled to the spectrophotometer and color database, determines a color formula that produces the measured color and satisfies accelerated weathering test requirements.
In a sixth embodiment, there is a color formulation tool. In this embodiment, there is a data extraction component that extracts color data from a color database. A color matching component determines a color formula that matches the color of a color standard and satisfies accelerated weathering test requirements from the extracted color data. A color prediction component predicts the shift in color for the color formula due to weathering.
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Barren James Paul
Graf John Frederick
Pickett James Edward
Shakhnovich Alexander Isaakovich
Evans F. L.
Geisel Kara
General Electric Company
Goldman David C.
Patnode Patrick K.
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