Spectrophotometers Measure Color to Help You Stay in the Black

Jan. 1, 2020
What is the number one problem for painters? Most will say "color matching." And so it has been for many years. The aids to painters have increased from chip books and color books to include variance decks, and the courses on color matching
ABRN: Spectrophotometers Measure Color to Help You Stay in the Black Spectrophotometers Measure Color to Help You Stay in the Black By JOHN PFANSTIEHL, Contributing Editor January 1998

What is the number one problem for painters? Most will say "color matching." And so it has been for many years. The aids to painters have increased from chip books and color books to include variance decks, and the courses on color matching have expanded and improved. However the colors themselves have expanded faster: mica metallics, mica pearls, pearls and tinted clears are all found in OEM paint today.

The problem of successful color matching is compounded by the fact that color itself is a perception. Every person differs in how he or she values the different aspects of color and in how discriminating they are in viewing color. Industry has long been trying to bring order to the messy field of human color perception. Try to imagine what a nightmare it would be for an auto manufacturer to assemble an interior with blue parts from perhaps 20 different suppliers if there was no objective way to measure color. To help solve this type of problem, the spectrophotometer has become one of the main instruments used by industry to set standards and monitor quality with regard to color.

Background

Although spectrophotometers are common in industry, including both automotive manufacturing and paint manufacturing, only in the last several years have they become available to directly help painters in collision repair facilities. Automotive refinishing has seen a number of major changes in the '90s. These changes along with the introduction of paint measurement by sophisticated instruments--which were already used in other industries--will profoundly affect the practice of future refinishing. The three main areas of refinish paint measurement are thickness, surface finish and color.

Electronic thickness gauges were the first of the modern paint measurement instruments available through the Big Three's dealer equipment programs primarily because paint thickness is one of the most critical factors in paint durability. Their relatively low cost, durability and ease of use has further facilitated their introduction into the PBE market.

The second area, measurement of surface finish, is also now possible with an instrument which is comparable to electronic thickness gauges in cost, durability and ease of use. These factors facilitate adoption of this technology and thereby will help establish objective measurable standards for finish quality in the refinish market.

Color measurement, as compared to thickness and surface finish measurement, is considerably more complex, and the price tag is in another league. To provide a color measurement system useful to painter, the development and refinement of the measurement instrument itself, the spectrophotometer, was only the first step. A tremendous amount of work was needed to analyze the rows and columns of numbers produced by the spectrophotometer and accurately connect these with the many thousands of paint formulas. Improvements and refinements in this process are continuing day to day and as a result the effectiveness of spectrophotometers to painters has increased over the years and will continue to do so. If you looked at spectrophotometers a few years ago and weren't sufficiently impressed, they're worth another look.

Color Basics

Skip this paragraph if you've already been schooled in color. Color has three main components:

* Hue. The normal definition of color--blue, blue-green, green and so on.

* Chroma. Saturation--is it a clear, intense blue or a muddy blue.

* Lightness. Is it a light blue or a dark blue? Spectrophotometers measure these three components of color and assign a numerical value to each.

Refinish spectrophotometers measure these three components from different angles. As we all know, the color of a vehicle can look different when viewed at different angles, and this is more pronounced with mica and pearl paints. If you have studied color matching, the terms flash (or pitch), face (head-on), and flop will sound familiar. These three angles are measured by all spectrophotometers. Four and five angle spectrophotometers are also on the market now. However, the number of angles the spectrophotometer measures doesn't complicate the use of the instrument for the painter, they are all measured automatically when the spectrophotometer is pressed down on the painted surface. The actual means for measuring the reflected light at these different angles consists either of a single fixed light source and multiple fixed detectors or of a single fixed detector and multiple fixed light sources.

Common Features

All spectrophotometers used in refinish have an integral internal light source. This enables use outside under any light condition--day or night--and its use inside is unaffected by fluorescent or other lighting sources. All are battery powered with rechargeable batteries, so that they can be used in the field or on the car lot.

All measure the hue, chroma and lightness of paints. They assign numerical values to each of these, and then internally or via a computer search the paint manufacturer's data base for the formula or paint code which will provide the closest match. In addition, spectrophotometers can suggest how to modify a stock formula to better match the paint which was measured.

Computer-based Spectrophotometers

Spectrophotometers used in auto refinish fall into two major categories: stand-alone or computer-based. The spectrophotometers designed to be used with a paint manufacturer's computerized system are smaller and are connected to the computer with a cable (after measurements are taken).

Advantages of computer based spectrophotometers are typically a larger number of paint formulas, updating with new formulas or corrections by disk or by a net, direct connection to smart scales for mixing the formulas, and automatic logging of paint use for job costing, or VOC regulations.

A computer-based spectrophotometer system may have one or two precision weight scales also connected to the computer. After the best formula is chosen, the painter simply follows the mixing sequence displayed on the screen. Each tint is weighed as it is poured, and if too much of one is accidentally poured, some systems will automatically adjust the amounts of the following tints to get the desired color. Computer-based systems can also keep a record of the formula as it was mixed for that job. This can be a big help if the same vehicle needs painting at a later time or could even help matching other vehicles with the same color.

Stand-Alone Spectrophotometers

A specialized computer system is not needed by stand-alone spectrophotometers. After taking paint readings, the display on the spectrophotometer gives the paint code for the formula with the closest match. The user then looks up the formula (for example on microfiche) and the spectrophotometer can supply further information on how to alter the formula for a better match. Updating of formula lists is accomplished by inserting new R.A.M. memory cards.

Strong Suit

Spectrophotometers have particular advantages for matching unknown colors, matching solid colors and for use with fleets. Factory color codes are often not available for custom colors or for vehicles which have had a color change. A spectrophotometer can be used to provide a formula instead of going through hundreds of color chips and then comparing the closest ones with the vehicle.

Fleet vehicles are often painted with specific corporate colors. These colors may not be represented by standard manufacturer formulas. In addition, the company which owns the fleet may require that the color on their vehicles fall within a specified tolerance. Spectrophotometers can both provide a formula and then document that the applied paint matches the company's standard.

Tips for Evaluating Spectrophotometers

For most shops, a spectrophotometer represents a significant investment. The decision to get one, and which one to choose, deserves some close examination. The first thing to consider is the status of your paint supplier. Are you or your company thinking of changing paint brands? This is critical because the spectrophotometers are designed for only one company's formula and tints, and in the case of computer based instruments, for only one company's computer system. Before making a purchase of this size, you want to make sure you'll be staying with that paint line for quite some time.

Next check out how effective the spectrophotometer is for your needs. If your jobber or warehouse has one, take a few problem color match pieces to them. Stay around to watch how easy or difficult the spectrophotometer is to use and how much time it takes. Then spray out the mixed paint to see how effective the spectrophotometer was at producing a blendable color. If it wasn't close enough on the first try, see how effective it is at providing useful information to modify the formula.

If the spectrophotometer makes economic sense, look at the warranty. Any instrument as complex as this can be expensive to repair. As one example of how a warranty can be structured, NAPA/Martin-Senour provides one year parts and labor, then for next two years there is a $250 fee per each service/repair. And finally, ask what type of training and technical support is provided; as an example, Sherwin-Williams has one full day of training included with the cost of the instrument.

Summary

The whole point of a color matching system is to quickly get a blendable match on the first mix. Keep that in mind as you examine the alternatives. Is a spectrophotometer for you? Not even the staunchest proponent would say a spectrophotometer is right for everyone. Some shops are fortunate to work on only a limited range of vehicles. As an example, when I worked at Corvette Center in Connecticut, we did not have many colors to deal with.

On the other hand, if color matching is an on-going problem for your shop, keep an eye toward spectrophotometers; some painters swear by them - and their effectiveness is improving all the time. Plus remember that sophisticated instrumentation has added value as a promotional tool. Having technology which your competition lacks helps win customers.

If you decide against spectrophotometers at this time, consider making an investment in in-depth color matching training, even if it costs a few thousand dollars, because proficiency in color matching is a key to keeping the green in your wallet.

Sponsored Recommendations

Best Body Shop and the 360-Degree-Concept

Spanesi ‘360-Degree-Concept’ Enables Kansas Body Shop to Complete High-Quality Repairs

ADAS Applications: What They Are & What They Do

Learn how ADAS utilizes sensors such as radar, sonar, lidar and cameras to perceive the world around the vehicle, and either provide critical information to the driver or take...

Banking on Bigger Profits with a Heavy-Duty Truck Paint Booth

The addition of a heavy-duty paint booth for oversized trucks & vehicles can open the door to new or expanded service opportunities.

Boosting Your Shop's Bottom Line with an Extended Height Paint Booths

Discover how the investment in an extended-height paint booth is a game-changer for most collision shops with this Free Guide.