Porsche PPV 4025 Exterior, Paint Jobs - Color Check - Painted Body and Fittings

The “ Porsche PPV 4025 Exterior, paintwork - Color inspection - Painted body and components” standard, developed by the Volkswagen automotive company , describes the color inspection procedure for Porsche vehicles. The technical content of the VA.PK.033 standard procedural instruction is included in this test standard.

Body and fittings painted in body color (exterior colors) are tested according to this standard. The color impression is influenced by various factors. Therefore, the test parameters for color control must be precisely defined and adhered to at all inspection locations (both inside and outside Porsche AG):

• At paint suppliers
• At suppliers of parts purchased in body color
• All contract manufacturers for Porsche vehicles
• At all inspection locations at Porsche AG:
  • During color comparison in the color matching booth / paint lab
  • During colour comparison of components in artificially lit inspection areas, e.g. incoming goods inspection
  • During color comparison on bodies, for example in paint inspection and polishing strip
  • When comparing colours on vehicles with additional parts, for example on the painting line, during vehicle delivery and during vehicle inspections

The Porsche AG paint laboratory is responsible for determining the test parameters. The relevant supplier or department at Porsche AG where the color control is performed is responsible for compliance with the test parameters, particularly the use of the correct types of light and observation from different viewing angles. Furthermore, the relevant supplier or department at Porsche AG where the color control is performed is responsible for documenting the results.

For the purposes of this standard, master samples are color samples created in accordance with work instructions AA.PK.O7.030. Samples are back-labeled and marked as master samples in accordance with these work instructions. These serve as color samples for all color checks. Any color samples labeled differently cannot be used for color comparisons.

Colour control during testing is carried out according to the standards VDA 621-409 and DIN EN ISO 3668 by visual comparison of the colour with the relevant master sample.

The table within the standard specifies the lighting to be used during testing. Mixed light should be avoided, meaning that artificially lit inspection stations should be shielded from sunlight or other prohibited light sources. This also ensures that color differences (metamerism) between different light sources are visible to the inspector.

The requirements for all test samples are determined as follows:

• The surface texture of the sample and the main sample must be the same.
• The gloss level of the sample and the main sample must be the same.
• The coating should be cloudless.
• Effect materials must match the main sample in size, quantity, and orientation.
• Test samples must be free of fingerprints, scratches and the like, if necessary the samples must be polished until a cloud-free surface is obtained.

Meanwhile, the test officer must be color blind and wear dull gray clothing.

Tests and methods for color comparison include:

• Colour comparison in a colour matching booth: Tests are performed with all three illuminants (D65, TL84 and A). The light incidence is always vertical from above, with a distance of 30 cm to 50 cm between the light source and the sample.

The master specimen is placed on the test specimen or test piece. Ensure the master specimen is perfectly flat. For slightly curved specimens, the position can be corrected by gently pressing down. Always observe at a 45-degree angle to the light source, with a distance of 60 cm to 80 cm between the eye and the specimen. Both the top view and the oblique view are evaluated.

• In-car color comparison: Use TL84 (indoor) light type for testing, or if in doubt, perform the test in natural daylight (outdoor). Illumination should be from above and, if possible, from the side. In daylight, the illumination should be diffused; if possible, the test should be conducted under a slightly cloudy northern sky. There should be no nearby colored objects that could reflect light. The distance from the light source should be 150 cm to 230 cm.

The master sample is placed in the body. The master sample must lie completely flat. For slightly curved surfaces, the position can be uniformed by gently pressing it. The edges of the master samples must be burr-free to avoid damaging the vehicle's paint. The angle of incidence cannot be precisely determined because the vehicle is illuminated from different angles due to its shape. Color comparisons are typically performed at a distance of 60 cm (arm's length) from different viewing angles: top view (0 degrees to the surface normal) and oblique view (various angles, preferably 45 degrees and -65 degrees to the surface normal).

• Colour comparison of components in artificially illuminated inspection stations: A TL84 illuminator is used, and illumination is preferably from above. The distance from the light source to the samples should be between 150 cm and 230 cm. If possible, observations should be made from a distance of 60 cm (arm's length) with different illumination angles and viewing angles. Due to the geometry of the component parts, the illumination angle cannot always be precisely defined. For large components, it is often only necessary to change the viewing angle. This allows for both top-view and oblique-view evaluation. For components installed in visually critical locations, quality assurance can determine the arrangement of the lights and the position of the component for colour evaluation.

The master sample is placed on the component. Care must be taken to ensure that the master sample is positioned at exactly the same angle. For slightly curved samples, the position can be uniformed by gently pressing it. For more curved samples, a definitive color assessment is not possible; only an acceptable overall appearance on the body can be determined. The master sample edges must be burr-free to prevent damage to the paint coating.

• Color tone assessment: The difference from the original sample is usually assessed (not vice versa). The type of deviation is indicated in the test report using the relevant key figures. A relative rating scale for visual color matching according to DIN EN ISO 4628-1 or DIN EN ISO 3668 is included in the standard.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services to businesses in accordance with the "Porsche PPV 4025 Exterior, Paintwork - Color Control - Painted Body and Fittings" standard.