Why doesn’t my shade match exactly?

A colour that ‘doesn’t match’ is rarely down to a faulty formula: it is almost always due to a variation, ageing or poor application.

A paint finish that does not match the vehicle perfectly does not necessarily mean that the colour code is incorrect or that the formula is faulty. The discrepancy may be due to several factors: the existence of variants for the same manufacturer’s code, ageing of the original paint, differences in the substrate, insufficient opacity or an unsuitable application method. With metallic, pearlescent or effect finishes, the orientation of the particles also has a significant influence on the final result. This is a common situation in bodywork: the colour prepared matches the code recorded on the vehicle, but a discrepancy remains visible after application. Before altering the formula, it is therefore essential to carry out a systematic diagnosis. This tutorial outlines the main causes of colour mismatches and the checking method used in the workshop to select the correct variant, and explains the method followed by the Carross workshop to achieve an accurate colour match. To identify the code itself, refer to the guide on finding a car’s colour code.

Tech’Team tip

The game-changer: Test cardboard and blended finish – the combination for profitability

1. The test cardboard: The classic mistake that undermines productivity is to blindly trust the manufacturer’s code and check the colour directly on the car whilst it is being applied. This is technically nonsensical. The test cardboard is prepared before the vehicle enters the spray booth. It has three essential functions:

• To validate the colour variant (or the formula measured by the spectrophotometer) in relation to the bodywork’s ageing.
• To check the theoretical coverage (how many coats are required depending on the primer shade).
• To finalise your application settings (pressure, distance, flow rate) for the base coat on metallic/pearlescent colours.

2. Matching to an adjacent panel: Many painters insist on painting ‘edge to edge’ to save clearcoat and preparation time on the neighbouring panel. This is a miscalculation. Attempting to manually adjust a formula so that it ‘matches’ perfectly (100 per cent) with a 5-year-old original paint takes hours of colour-matching work, requires multiple test panels, and often ends in failure. Conversely, the flush finish guarantees cost-effectiveness:

• The preparation and sanding of the adjacent panel take 15 to 20 minutes at most.
• Applying a blending agent and blending the matt basecoat makes any visual transition invisible to the human eye, even if the colour match is only 90 per cent.
• The result: zero customer returns, zero time wasted tinting the base to the exact shade, and a maximised first-time success rate.

In summary: Don’t waste two hours trying to find the perfect shade for a risky edge-to-edge match. Take 20 minutes to prepare a blended transition using the best available variant.

The essentials in a nutshell. Paint prepared using the correct code may not match for several reasons: there may be several variants for the same manufacturer’s code; the original paint may have changed due to UV exposure, washes and conditions of use; the primer, base coat or undercoat colour may influence the finish; the thickness, dilution and application method may alter the perceived colour; the orientation of the particles may change the finish depending on the viewing angle; a difference may only be visible under certain light sources. The correct method is to check the colour on a test panel, apply a clearcoat, compare several variants if necessary, and validate the application before altering the formula.

1. Diagnose first and foremost

• Difference in intensity across the entire component: — Incorrect shade variant. It is essential to check the variants of the colour code (lighter, darker, more yellow, etc.) and to produce a clearcoat test cardboard before application.
• A sharp contrast between the new part and adjacent components: — Ageing of the old finish. An edge-to-edge joint must be avoided. A recessed joint must be provided on the adjacent components.
• Correct colour on the front, but different on the reverse: — Incorrect orientation of metallic/pearlescent paints. Adjust your application settings: higher pressure and a greater distance lighten the colour; lower pressure and spraying from close range darken the finish.
• Lack of depth or visible substrate: — Insufficient theoretical coverage. Either basecoats are missing, or the colour of the primer (undercoat) is unsuitable.
• Colour varies depending on the light source: — Metamerism. Checks must always be carried out under a colourimetric inspection lamp AND in natural light.

2. The necessary equipment

• Custom-coloured bodywork paint
• Test cardboard
• Multi-temperature daylight lamp

3. Step-by-step repair

1. Confirm the code and its variant. Note down the exact colour code, then check whether there are several variants for this code: this is the number one cause of colour mismatches. See ‘Finding the car’s colour code’.
2. Compare against the test cardboard. Apply the chosen formula to the test cardboard, ensuring it matches the colour of the original primer. You must apply a clearcoat to the cardboard before comparison.
3. Check under standardised lighting. Assess the test cardboard directly on the bodywork (which should be cleaned and polished beforehand if necessary) under a high-intensity IRC inspection lamp and in daylight to rule out any risk of metamerism.
4. Adjust the application. Ensure the correct thickness, distance and pressure: on metallic and pearlescent finishes, it is the application that determines the orientation of the flakes and therefore the perceived colour.
5. Blend technique. On older vehicles, apply a blending agent (blender) to the adjacent panel to blend the matt basecoat, ensuring an invisible visual transition.
6. Pre-clearcoat simulation. If you are checking the blend on the substrate before applying the clearcoat, use a specific degreaser or a clearcoat simulator. Never judge a colour on a dry matt basecoat.
7. Check before applying the clearcoat. Check the blend on a fresh base coat, at the correct opacity, before applying the clearcoat.

4. Common mistakes to avoid

• Assessing colour on a matt (unvarnished) test cardboard: the clearcoat alters the refraction of light and the colour saturation.
• Changing a base formula without first checking the other factory variants available.
• Insisting on painting edge-to-edge on a vehicle instead of blending the colour onto the adjacent panel.
• Neglecting the influence of the primer shade beneath low-coverage colours (e.g. reds, yellows or three-coat finishes).
• Only checking the colour under the standard lighting in the booth (which is often prone to metamerism).

5. How to choose your products

If there is a colour difference on a new part, first test another variant of the code before altering the formula.

Old, dull bodywork: Perform preparation of the adjacent area and use a blending binder for a seamless finish.

Matt basecoat with effects (Metal/Pearlescent): Control the application haze. This is the final application step that locks in the orientation of the particles.

Carross’s advice: Manually adjusting the base components of a formula should be a colourist’s last resort. Always prioritise finding a suitable variant and using blending techniques.

6. FAQ

How do I find out the exact colour of my car?

The colour is specified by the manufacturer’s colour code, which can be found on the vehicle’s identification plate (in the engine compartment, on the door pillar or in the boot, depending on the make). However, the code alone is not enough: you must then identify the correct variant from among those associated with that code. See ‘Finding your car’s colour code’ for the full method.

My paint has the correct code but doesn’t match – why is that?

Most often, this is because there are several variants for the same code, and the one applied is not the one for your vehicle. Ageing of the original paintwork and the application (thickness, opacity) are the two other common causes. The formula is rarely to blame: first, you look for the correct variant and then compare it with the nameplate.

Do I need to redo the whole formula if the colour doesn’t match?

No, that’s the last thing you should do. First, try another variant of the same code, check the opacity and application, and inspect it under standardised lighting. Correcting a formula blindly often makes the discrepancy worse. Formula correction should only be carried out once these causes have been ruled out.

Why is the colour match visible on an old car?

Because the original paint has aged and no longer matches the shade of its original formula, whereas the new part is still at the original colour value. The discrepancy isn’t in the paint can but in the age of the bodywork. The solution is to blend the paint into the neighbouring areas rather than applying it with a sharp edge-to-edge finish, which would always give the difference away.

Can I order paint that’s already the right shade for me?

Yes, a custom-mixed paint is prepared based on your vehicle’s colour code and variant, ready to use. To order a custom-mixed paint, you must provide the exact colour code and, if possible, the variant.

Updated: 30/09/2026

Explore the Preparation / Paint / Finishing section and our bodywork guides and tutorials. Got a technical query? Contact the Carross Tech’Team: +33 (0)1 60 27 20 19.