PAINT SHADING/BLENDING—HOW, WHY AND WHEN
Repainting typically falls into three categories: touch-up repainting, partial repainting and total repainting. Here, we’ll focus on partial repainting, which is where paint shading/blending comes in. If you’ve ever repainted a door and didn’t blend in the paint, it was probably easy to see that the door had been repainted when the vehicle was in full sunlight because the repainted area didn’t match the original color. To properly restore paint to like-new condition, paint shading or paint blending is required.
Paint shading is important because no two paint jobs are alike. Even at the factory, there can be slight variations based on the conditions the day the vehicle was painted. Temperature, humidity, different paint brands used at different assembly plants, different types of equipment, and how long the paint had been flowing in the system—these factors all may affect the final color. Another element to take into consideration is the way your facility repaints a vehicle.
While Toyota primarily uses a waterborne paint process, many collision repair facilities (excluding those in states that mandate the use of waterborne) use solvent-borne paints. Each paint company may use different pigments, and their formulas will also vary in chemistry. Paint color also varies from batch to batch. Paint companies come up with their own proprietary formula for the standard color and then create alternate formulas to match known variations in the paint as it is produced. For example, Desert Sand Mica (4Q2) has a standard formula and 13 alternate formulas.
"If you’ve ever repainted a door and didn’t blend the paint, it was probably easy to see that the door had been repainted when the vehicle was in full sunlight because the repainted area didn’t match the original color. To properly restore paint to like-new condition, paint shading or paint blending is required.”
Other factors that impact the look of the final color include color or shade of primer sealer, metallic flake orientation, the number of layers of pearl or mid-coat used, the type of paint gun, mixing volume and air pressure at the spray nozzle—even the angle and distance at which the painter holds the spray gun has an impact. And finally, the viewing angle and light source can affect paint appearance—paint looks different under various lighting sources such as inside the shop versus in full daylight.
What’s the solution? Paint shading/blending, tricks the eye into seeing one continuous color—but you need to work at it to make it look just right.
Start with the paint: Once you mix the formulation, spray the paint on a card, clear-coat it, let it dry, and then head outside with the card and the vehicle to see how they compare. Keep modifying the formula, gun settings and techniques until the vehicle and the card look to be as close as possible to each other.