Colour Fidelity: Why Colour Can Sometimes Appear Different

Why does a colour that seemed perfect when chosen appear different once applied?

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The perception of colour is the result of a complex interaction between light, materials and the human eye. Understanding these mechanisms is crucial, especially for industries such as powder coatings, where colour fidelity is synonymous with quality and reliability.

How Colour Perception Works

When light hits an object, some wavelengths are absorbed and others reflected. The colour we perceive depends on the reflected light, but it is not just a matter of physics: the human eye interprets colour through three types of photoreceptors (S, M and L cones), each sensitive to a different wavelength range.

Red, for example, is mainly perceived by the L cones, which have a peak sensitivity around 565 nm – a wavelength closer to yellow than to pure red. This makes the perception of red less accurate than other colours, an aspect to be carefully considered in areas where colour accuracy is crucial.

Lighting and Environment: Critical Variables

Not all light is equal. Light sources have different spectral distributions, which influence the way colours are perceived. The environment also plays an important role: coloured walls, reflective surfaces or different viewing angles can significantly alter colour rendering.

Metamerism: One Colour, Several Faces

A phenomenon closely related to lighting is metamerism: two colours can appear identical under one light and completely different under another. This effect is particularly problematic for complex colours such as red, but can affect any hue. Testing colours under different light conditions is therefore essential to avoid surprises after application.

Pigment Quality Counts

Colour rendering also depends on the chemistry of the pigments. Pure pigments selectively reflect the desired wavelengths, while contaminated or unstable ones can distort the final shade.

In the case of red, the difficulty is twofold: not only is it more difficult to perceive accurately, but it is also more complex to produce in a pure and stable form. Impurities or variations in composition can in fact lead to unwanted shades.

How to Ensure Superior Colour Fidelity

Reproducing a colour faithfully is not the result of chance, but the result of technical choices and rigorous controls:

• High Quality Pigments – The use of pure and stable pigments reduces unwanted colour deviations
• Instrumental Quality Control – Each batch is checked with spectrophotometers, which are more precise instruments than colorimeters. These devices measure the reflection of light on a surface and compare it to colour standards such as the CIE Lab, which defines colour in a three-dimensional space (L = brightness, a* = green-red axis, b* = blue-yellow axis)
• Standardised Illumination – Tests are performed under different light sources to assess colour stability under real-life conditions and avoid surprises after application.

How RIPOL Tackles the Challenges of Colour Fidelity

At RIPOL, colour fidelity is not just a matter of aesthetics, but a technical and quality commitment that permeates every stage of the production process. The aim is to ensure that every shade – particularly the most complex ones, such as red – maintains consistency, stability and brilliance over time. This result is the result of an integrated approach combining scientific rigour, advanced technology and a quality-oriented corporate culture.

Here is how it is ensured:

• Selected Pigments – Use of high-purity pigments, chosen for their chemical stability and consistent colour rendering
• Advanced Instrumental Controls – Each formulation is tested with precision spectrophotometers, in compliance with international standards (CIE, ISO). These controls make it possible to detect even the smallest colour variations, guaranteeing very high quality consistency between different batches
• Multi-Lighting Test – To avoid metamerism effects, the colours are tested under different lighting conditions (daylight, LED, incandescent). This makes it possible to predict the visual performance in any real context of use
• Certified Quality System – RIPOL operates according to the ISO 9001 standard, which certifies the adoption of a structured quality management system geared towards continuous improvement. In addition, many of the product series (52L, 55R, 56L, 58L, 59L) comply with QUALICOAT specifications, which certify the durability and resistance of powder coatings in outdoor environments. Although these certifications do not directly relate to colour fidelity, they are a guarantee of the rigour with which the company handles each stage of the production process
• Constant Research and Development – Innovation is central to RIPOL’s strategy. The company continuously invests in new formulations capable of guaranteeing high performance even in complex environmental conditions. An example is RAL 6031-F9 Matt Bronze Green, developed for military applications: this colour requires exceptional colour stability in extreme environments, where even the slightest shade variation can compromise functionality and camouflage.

Colour fidelity is a technical challenge that requires expertise, rigour and innovation.

RIPOL has been working for years to transform what for many is a critical issue into a recognised strength: reliable, repeatable and consistent colours over time, even under the most demanding conditions.

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