Color matching is a benchmark of quality workmanship

IMAGES / AL THOMAS

Of all the things customers could look at first when picking up their vehicles following collision repairs, color match usually is the first (Fig. 1), or at least a close second. Despite the degree of difficulty involved in many facets of restoring a vehicle to its pre-accident condition – such things as complex cutting and welding, body alignment and restoring a vehicle's crash-worthiness – consideration of these often comes after the customer is assured that the color matches. It's as if the benchmark of quality workmanship is color match. This means overall quality will be judged, at least first, by how well the color matches. How's that for a little pressure, painters?

There are a multitude of variables that affect color match. A painter has control over some, such as spray technique and reduction choices, but there are other areas where the painter has little or no control, such as weather conditions. For these, the painter must anticipate how the variable will affect the color outcome and adapt to it. It's complex and can be confusing.

Even the language used to describe the process can be confusing. For example, color match and tinting are used interchangeably, although they describe different processes. Color match is the art and science used to paint a repaired area of a vehicle so the new color is undetectable. Tinting is the art and science of choosing the correct color tint to add to a paint to bring it closer to the original color for that undetectable repair. With this in mind, the statement "tinting should be your last resort when color matching" is understandable.

Tinting is difficult. It's especially so if you don't have a firm understanding of color and how it works before attempting the task. Simply looking at a mismatched color and randomly grabbing a color off the mixing bank will, in all likelihood, result in failure. Many a painter who's had a successful career doesn't tint. For those who do successfully, it's a process that must be done regularly to remain profitable (fast) and accurate. Luckily, there are many techniques that can be employed to correct a mismatched color without resorting to tinting. So before you grab that tint and add it, consider the following suggestions.

Before you tint

A. Retrieving the OEM Code. Often, the cause of the color mismatch is the OEM color code or paint manufacturer's paint code is misread, guessed at or chosen incorrectly. The best place to start is by confirming the color code (Fig. 2). The use of vehicle identification number for color retrieval or using a spectrophotometer (Fig. 3) has helped with this task, but cost may be prohibitive if you don't paint enough vehicles to justify the expense. However, they're accurate, and when used correctly, can eliminate many common color match problems. Some systems have an electronic spray-out panel. This usually eliminates the need for a panel. Once the paint formula is correctly identified, it's time to mix.

B. Mixing the formula. Mixing the paint formula is critical (Fig. 4). Measuring each tint correctly can mean the difference between a color that's a match and one that's off. Each tint isn't created equal, so a painter can't say that if he gets within plus or minus 1 it will be OK. Some tints are higher strength than others and will move the color fast. Others that vary plus or minus 1 may have little effect on the color, so measuring each tint correctly is critical.

C. Guard against a corrupt rack. If a mixing bank isn't handled (Fig. 5) correctly, it can become corrupt. If a paint, say a coarse metallic, is taken off the mixing bank before it's agitated and used properly, the thinner paint at the top, which rises as the metallic settles, will change the tint within the can. Every time after that tint is used it will be more concentrated and create a mismatch. Finding one or more of these compromised tints too late will be frustrating and costly. Follow the manufacturer's recommendations for tint agitation and do not corrupt the paint rack.

D. Choosing reducers and spray technique. Choosing the correct reducer and spray technique for specific colors and paint types is critical. Different reducers can quicken the repair process and make the shop more profitable, but the choice of reducer can affect the color. Tip size, air pressure and application technique affect the color. The wetter a paint is applied, the darker the color will be, and the drier the application is, the lighter the color will be. Reducers that are correct for the weather conditions and allow the paint the correct flash time will be more likely to have a correct color match. This is why such things as proper gun set-up, air pressure, gun angles, distance, overlap and flash time are critical for color match.

E. Spray-out panel. Is a spray-out panel (Fig. 6) necessary for every vehicle you paint? No. But if there's any suspicion that the color may not be a blendable match, a spray-out panel should be made. Most importantly, when making a spray-out panel, all procedures – the reduction, spray technique, flash time, gun set-up – must be identical to those used when painting the vehicle. If not, the comparison won't be accurate, which means even the clear must be put on and dried before it can be compared to the vehicle (Fig. 7).

When comparing a spray-out panel to the vehicle, precautions should be taken to ensure an accurate reading. First, light must be sunlight or color corrected light so proper identification is possible. Most shop lights aren't the proper type of light to use when identifying color match. Take the vehicle outside, or use a tool such as a sun gun, which has the correct spectrum of light for identification.

Don't stare at the panel for long periods of time. When you look at the two colors continually, your eyes will develop color fatigue, and slight variances in shade will become difficult to see. Look at the vehicle, comparing it to the spray-out panel, for 15 to 20 seconds. Then look away for at least the same amount of time before looking back at the two colors. This will make identification more accurate.

The paint should be viewed head on (looking down at the two panels) and on the flop (a 45-degree angle). Look with the light source at the painter's back (Fig. 1) and in front of the painter. A more accurate color match can be made by viewing all three angles.

F. Another thing to consider. Are you blind? This isn't a bad question to ask a painter because every painter should know if he has a color deficiency. Twenty-five percent of males have some color recognition difficulty. A quick online test can tell you if you have color identification problems that need additional investigation. The test, called the Ishihara color test (http://colorvisiontesting.com/ishihara.htm) can be a good first step. If a painter has difficulties identifying colors, an eye doctor can diagnose how severe the problem is.

Technique: blend it, send it

It could be argued there's no perfect color match. Whether because of the age of the paint, the conditions the vehicle is painted in, or a multitude of other conditions that affect a perfect match, blending is the best and most profitable method of refinishing a vehicle. Blending allows the color being applied to the vehicle's color to make a gradual change from old to new. If there's a slight difference of shade color, the eye is tricked into not seeing the differences. Panel painting, during which the new paint is stopped at a panel such as, say, a fender, with the vehicle door having the original color, will draw attention to the differences. Because of the advantages of blending, most, if not all, repair areas should be blended.

Tinting

If you've done all you can to ensure the color is correct and there's a blendable match and it still isn't, there's no alternative but to tint the formula so it can be blended correctly. Identify how the paint that's been mixed differs from the vehicle being painted. A habit that should be established when comparing a spray-out panel to the vehicle should be to use the expression "the vehicle is _____ than the spray-out panel." This helps confirm the vehicle is what's being matched, and the formula needs to be adjusted to that standard. If one says the spray-out panel is darker than the vehicle, it can be confusing as to what type of adjustment should be made.

Color can be adjusted in three directions (Fig. 8). First a color's values are the lightness and darkness of the color or the center of the color. This can be seen more easily by looking at a Mensell color tree, which has three dimensions:

The center or the axis of the tree that represents value or lightness and darkness of that color – in this case orange. On the left are seven squares that range from lightest at the top to the darkest at the bottom. This represents the value of this color.
The hue, or color (in this case orange), is represented by the outermost part of the tree. Two distinctly orange squares are at the outer most portion of the tree.
Chroma is represented by the seven squares running on the third horizontal plane, with gray oranges to the left and a clean bright orange to the right. These three dimensions help establish a true color description to use when tinting.

The hue or color can be viewed in a certain order: ROY G BIV, a memory device you may have learned in elementary school. Knowing this order – red, orange, yellow, green, blue, indigo and violet – helps. When tinting, remember a color can only be off toward one of its direct neighbors. Orange can be off only toward red or yellow. If a red vehicle is compared to spray-out panel, the vehicle can be more (or less) only orange or violet than the spray-out panel. By knowing this and using the formula and a tint plotting map, the most appropriate tint can be chosen for tinting.

Don't tint outside the formula

If all the pretinting precautions have been chosen correctly and the formula is correct, all the tints to make a blendable match are in that formula (Fig. 9). Don't go outside the formula and choose a tint that's not in the original formula. In the formula in this illustration, red is the most dominant color with 901.6 parts, with violet, the next most dominant color, at 33.1 parts. If you remember ROY G BIV, violet is the next closest neighbor to red on its right. In this case, the vehicle could be more red or violet than a spray-out panel. The black and white have little effect on the color (hue) but will affect the lightness or darkness (value) of that color. The clear has little effect on the color (hue), value or chroma. For tinting, choices have been narrowed to the red or violet to adjust hue and white or black to adjust the value.

Tinting steps

1. Make a spray-out test panel of the color you think may be difficult to match.

1.1. Use the exact gun set-up, spray technique, reduction, sealer shade, flash time, etc., as will be used when spraying the vehicle for the spray-out panel (Fig. 6).

1.2. Using a color corrected light source, compare the vehicle to the spray-out panel (Fig. 7).

1.3. If the color is a blendable match, then blend it and send it. If not, while avoiding eye color fatigue, evaluate the three dimensions of the color – its hue, value and chroma.

2. Plot the color variance.

2.1. Using a color variance plotting graph (Fig. 10), plot the three dimensions of color: value first, then hue, and finally (and only if needed), the chroma. (Often, but not always, the chroma will self-adjust when value and hue are corrected.)

2.2. When the differences are noted using the original formula a tint can be chosen to adjust the color.

2.3. Each adjustment made should be recorded, so if the new color is correct, the second half or any additional mixing can be duplicated.

2.4. Take a portion, such as half of the original paint, and adjust it. With a second spray-out panel, check for a blendable match.

3. Record all adjustments on the back of the spray-out panel (Fig. 11) and keep this for future reference.

3.1. A file of old spray-out panels can be invaluable when the same color is encountered again.

Mastering a difficult task

When tinting is viewed as a gift that only few possess, it could make the process seem so difficult many won't attempt it. But when broken down into its elements, adjusting those in a proper order, it can be made into a process many, if not all, could do.