Paint Matching (Color Mixing Work) - Key Points in Color Comparison and Matching

1.	Key Points in Color Comparison and Matching

Colorimetry Steps:

When comparing colors, usually the body panel right next to the repair area is used. Make sure to remove any stains on the panel by polishing with a very fine compound for an accurate comparison.

Prepare a test piece of the same material and size. For ease of comparison, pace the test plate on top of the actual vehicle panel. Then place an achromatic colored magnet sheet with an opening on top.

Lighting and Environment:

The ideal type of light when comparing colors is diffused daylight. However, color matching is not always done outside under daylight. In such cases, use an artificial light source which offers a wavelength very close to sunlight.

In case of using an artificial light source to compare colors, prepare a light with 1,500 to 3,000 lux of illuminance. The actual required level of illuminance differs by color.

NOTE: The definition of diffused daylight is a light from a North facing window that avoids direct sunlight from three hours after sunrise until three hours before sunset.

View Angle and Distance:

Check from at least three different directions at a distance of 3?5 m (10?16 ft) away.

Color Change Between Immediately After Painting and After Dry:

The color on the test plate immediately after painting and after complete drying will be different. This is due to specific weight of pigment. Pigments with light specific weight will rise to the surface when the paint dries

In normal cases, solid colors tend to be darker and metallic pearl colors tend to be lighter as they dry. Make sure to compare colors for matching only after they are completely dry.

Color Changes Caused by Clearcoat:

Metallic, pearl, and solid colors change their hues after clearcoat application. When working with clearcoat paint, only compare the colors for match only after clearcoat is applied when using clear coating.

Paint Colors		After Clearcoat
Solid	General Colors	Becomes yellowish if painted repeatedly
Solid	Black	Looks whitish when seen from the side angle
Metallic, Pearl	Silver Metallic	Looks whitish when seen from the side angle, darken from 45 °
Metallic, Pearl	Colored Metallic, Pearl	Becomes deeper and brighter

Color Changes Caused by Polishing:

Some paint colors change after polishing. For these types of paint, fully dry then polish the test piece. Compare the colors after polishing.

Mixing Hardener:

Dual-component paints tendency to lighten the base resin color when mixed with a hardener. Compare the color match only after the specified amount of hardener has been mixed with the paint.

Color Change as the Result of Spray Condition:

In particular, metallic and pearl colors may change hue according to the paint particle arrangement. This can be affected by the type and amount of paint reducer/thinner dilution or spray gun adjustment.

Generally, because a wet paint coat has a systematic arrangement of metallic particles, dense pigments stay close to the surface of the paint layer which makes the paint look deeper. Dry paint coats have an irregular arrangement of metallic particles, where irregularly arranged pigments stay close to the surface of the layer. This makes the paint appear lighter.