Color Quality Indicator Mapping for Paint Control

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Solution Overview

Problem

Current methods for color quality control of paints struggle to effectively assess and compare paint colors applied to different surfaces, particularly with effect paints, as they do not account for varying behavior on different substrates and surfaces, leading to inconsistent external appearances.

Innovation Solution

A method and system that determine multiple color quality indicators by calculating color differences and normalizing colorimetric coordinates across various measurement geometries and light sources, using a mapping rule to assign a scale value for each indicator, considering the specific behavior of paints on different surface elements and control surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple measurement geometries and light sources are used to assess paint color, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecolor measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the color assessment into multiple independent measurement geometries (45°/0°, 75°/0°, 75°/45°, gloss 20°/75°) and light sources (D65, TL84). Each measurement is performed separately and then integrated through a standardized mathematical model, allowing comprehensive color evaluation while maintaining manageable system complexity through modular measurement approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal assessment system that evaluates paint color across multiple surfaces (vehicle bodies, add-on parts, control plates) using the same spectrophotometer and measurement protocols. The standardized color difference calculation and normalization methods enable the system to function universally across different substrates and painting conditions, eliminating the need for substrate-specific measurement equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If comprehensive color assessment across different surfaces is performed, then reliability of color control is improved, but loss of time increases

Engineering Contradiction:
Improvecolor control reliabilityVSAvoidassessment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary normalization of colorimetric coordinates and establishes standardized weighting factors for different measurement geometries before final color difference calculation. By pre-defining the assessment protocol and normalization parameters, the system prepares the data structure in advance, enabling faster final evaluation across multiple surfaces without repeating the entire analysis process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms raw colorimetric coordinates into normalized parameters with standardized weighting factors that account for different surface types and painting conditions. This parameter transformation consolidates complex multi-surface data into comparable metrics, allowing rapid assessment of color consistency across vehicle bodies, add-on parts, and control plates without analyzing each surface independently in detail.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If effect pigments are considered in color comparison, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveeffect paint color precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent adds measurement angle as an additional dimension for effect paint assessment by incorporating 45°/0°, 75°/0°, 75°/45° geometries alongside traditional measurements. This dimensional expansion captures the angular-dependent optical properties of effect pigments, providing comprehensive color characterization without requiring complex specialized effect measurement equipment beyond standard spectrophotometers.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for a comprehensive and standardized assessment of paint quality, enabling quick and simple evaluation of paint batches across different surfaces, ensuring consistent color performance and quality control.

Implementation Method 1

the mixed paint is measured spectrophotometrically

Methodology Applied
Scientific EffectSpectrophotometry: Absorption Spectroscopy

Implementation Method 2

determine, for a number of measurement geometries and a number of light sources, colorimetric coordinates of a color reference and colorimetric coordinates of a paint

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3692348B1Method and system for determining a number of colour quality indicators for a colour control of a varnish
Publication Date: 2023.06.07 BASF COATINGS GMBH
  • EP3692348B1 patent drawingFigure 1
  • EP3692348B1 patent drawingFigure 2
  • EP3692348B1 patent drawing

AI summary

The invention relates to a method for determining a plurality of colour quality indicators for a colour control of a paint, in which colorimetric coordinates of a colour reference and colorimetric coordinates of the paint are determined for a plurality of surface elements painted with the paint, each with a spectrophotometer for a number of measurement geometries and a number of light sources, wherein, for every measurement geometry of the number of measurement geometries and every light source of the number of light sources, respective colour differences are calculated from the colorimetic coordinates of the colour reference and the respective colorimetric coordinates of the paint for the plurality of surface elements painted with the paint, wherein the respective colorimetric coordinates are scaled with a respective weighting factor, wherein each of the plurality of colour quality indicators is determined at a scale value of a predefined scale by means of a mapping of functional values defined by a mapping rule, said functional values each being determined for the number of measurement geometries and the number of light sources by means of a mathematical correlation - specific to the respective colour quality indicator - between colour differences of at least one of the surface elements. The invention also relates to a corresponding device.