Considerations in Adopting A Total Approach To Color
The Technology of True Color Communications for the Plastics Industry
A White Paper by Datacolor
It started with a national competition to develop a satisfactory substitute for natural ivory for a U.S. manufacturer of billiard and pool balls. From that time in 1860 to the present, the development of plastics has been refined to encompass an increasing variety of industrial and consumer applications throughout the United States and the world. As those in the industry know, the manufacture of plastics and plastics products also is more complex than ever before. Some of the reasons for this complication include: the discovery of new sources of raw materials; the development of new additives such as ultraviolet stabilizers to protect against weathering; the heightened regulations involving wastes and the environment; and the increasing just-in-time push to deliver it all, better and faster.
Color is no exception to today's increased demands on plastics processes. If anything, color often remains the first, best test of a product's quality - and your customer's acceptance of the job on the first run. Color communication is a total approach to color -- from the time it is conceived as a design concept to the delivered component or finished product. The implications of a total approach to color for the plastics industry – and how the latest technology makes it all possible - constitute the subject of this white paper.
The Color Evolution & The Human Element
Naturally occurring white light, or daylight, holds all the colors in the human visible spectrum. This phenomenon can be seen when a prism splits the light into its many component colors. Sir Isaac Newton is the first person known to report this effect in 1666. Since then, scientists, mathematicians, even artists, have sought to categorize and define color -- with the goal of effectively communicating color and with varying degrees of success.
Communicating color has evolved from purely subjective descriptions of color by the viewer to mathematical theories used to create color matching and control functions that produce repeatable standards. The latter includes the classical equation by color measurement pioneers Kubelka and Munk as well as later theories which sought to perfect color matching through models based on tristimulus (three coordinate) or spectral (wavelength) data.
Color system suppliers such as Datacolor successfully translated these mathematical formulas into sophisticated systems to help coatings processors and colorant suppliers "standardize" the basically non-standard art of coloration: Equations to deal with different substrates and pigments; instruments to handle varying materials; and, techniques to offset the variables of the coatings process itself. Yet challenges in communicating color have remained, primarily because humans remain a necessary part of the equation. Regardless of how many numbers are assigned to a color, we don't see in numbers. We can't visualize precisely what another person means by "fire-engine red." Also, color is both a physical and psychological response to light. When a paint pigment such as titanium oxide, for example, strongly scatters light, it yields a white effect. When another pigment absorbs certain wavelengths of light, it produces a colored effect. In addition to this physical phenomenon, each viewer brings a different response to the same stimulus. These differences can be due to age, fatigue, color vision defects, or experience.
Consider how these human factors impact the color matching process in this typical scenario: the designer struggles to communicate precisely the color he or she has envisioned, using physical samples and describing how the proof should vary from the sample – i.e., warmer, brighter, bluer. The colorant supplier tries to match each sample, but still doesn't satisfy the design spec because the sample is only a starting point. Not only is the designer limited to feedback about the sample in the most subjective terms (e.g., by talking it through), but the sample the supplier was given to match may not be the same material as the final product. The plastic on which the color is adhered, whether it's opaque or transparent, flat or round, also affects perception of the finished color as surely as does the other considerations.
A New Approach To Color
Today, it is possible to approach and manage color differently. By employing the most advanced computer technology, leaders like Datacolor have come full circle, closing the "color communications loop" quite literally from mind to market. What does this mean for today's plastics industry? First, let's look at the potentially, significant business problems resulting from this trial and error color matching process: described above:
- The designer is unhappy – having spent valuable time looking for physical samples and trying to describe how close the final result has come to matching the design color.
- The colorant supplier is unhappy – having borne the cost of making proofs and express shipping them to the designer
- The manufacturer is unhappy – having had to wait extended days or weeks during the trial and error process and/or rejecting the first shipment as off-color.
Something to keep in mind, however: not every computerized system will deliver the level of digital sampling discussed here. The monitors must be calibrated to such a precise extent that two or more monitors reproduce a color so precisely we can not visually detect a difference. A single monitor must be able to repeat color day after day, with the same precision. In addition, the calibration must be device independent so that accurate RGB « CIELAB conversion is permitted using virtually any monitor and the transfer of color is possible between any two monitors. Finally, the software must be designed to allow users to conveniently create, change and visually compare colors on screen. Once the on-screen color is created, the software then, in turn, should automatically compute reflectance and L,a,b data which is the digital "signature" of that color. The system should accept measurements by a spectrophotometer or input as L,a,b data and instantly transform the data into visual color on the screen for evaluation or adjustment.
Color is universal and powerful. From the late 1800s and the advent of plastics to the wide variety of plastics applications today, it frequently is the decisive factor in determining the final quality and appeal of a plastics product or component. The mastery of color encompasses many scientific laws and subjective factors -- appearance, light, object, and material. Progressive color system suppliers like Datacolor recently have combined the efforts of all professionals in the color field -- researchers, colorists, engineers and technicians -- to deliver a total approach to color management in today's plastics industry.
Datacolor, 5 Princess Road, Lawrenceville, NJ 08648. Tel: 609-924-2189 ; Fax: 609-895-7472 .