A Practical Guide to Colour Matching Paint Codes

A paint code can turn a frustrating repair into a straightforward job - provided it is the right code for the right surface. This guide to colour matching paint codes explains what those references mean, where to find them and how to order a paint that looks right and performs properly once it is applied.

Whether you are refreshing UPVC window frames, touching up a kitchen unit, restoring a tractor panel or repairing a car, colour is only one part of the specification. The coating also needs to suit the substrate, the required finish and the conditions the item will face.

What a paint code actually tells you

A paint code is a reference used to identify a specific shade within a colour system or manufacturer range. It gives a paint mixer a reliable starting point for producing that colour, rather than asking them to work from a vague description such as “dark grey” or “sage green”.

Common references include RAL, British Standard, NCS, Pantone and named decorative colour ranges. Vehicle manufacturers use their own codes, while window and door products may be specified by a RAL colour or a foil reference. Digital values such as RGB, Hex, CMYK, HSL and LAB can also be used to communicate colour, especially for branded fittings, signage and interior design schemes.

The code matters because two colours that look similar in isolation can look noticeably different side by side. A slightly warmer white on a replacement door handle, a blue-grey that is too dark on a garage door, or an incorrect red on agricultural machinery can make a repair stand out more than the original damage.

A code is not always the whole story, however. It identifies the target shade, but the final appearance is affected by gloss level, texture, coating type, spray technique and the colour beneath it.

Guide to colour matching paint codes by project

The first job is to identify which type of code your project uses. Do not assume that every reference follows the same format or that a named colour has one universal formula.

RAL and British Standard colours

RAL codes are widely used for metalwork, doors, windows, industrial equipment and commercial projects. A RAL reference usually consists of four digits, making it a practical choice when matching architectural components and fabricated items. British Standard colours are also common across property maintenance, safety markings and older specifications.

If you have a confirmed RAL or British Standard code, use the complete reference when ordering. Do not rely on a screen image or a colour name alone. Screen calibration, room lighting and photography can all alter how a shade appears.

Decorative named colours

Farrow & Ball, Dulux and Valspar shades are often requested for furniture, radiators, skirting, internal doors and other home improvement projects. The colour name is useful, but it must be supplied accurately, including the brand. Similar names occur across different ranges and are not interchangeable.

For kitchen cabinets or fitted furniture, check whether your chosen paint needs to match a wall colour exactly or simply sit alongside it. A direct match can be right for a repaired panel. For a broader refurbishment, a sympathetic alternative may be more forgiving if the existing finish has aged or faded.

Vehicle and machinery paint codes

Car paint codes are normally found on a manufacturer label, often in the door shut, engine bay, boot area or service documentation. Their location varies by make and model. The registration number is not a paint code, and the vehicle’s badge colour description is rarely precise enough for an accurate repair.

For classic cars, commercial vehicles, plant and agricultural equipment, a code may be missing, obsolete or complicated by previous resprays. In that situation, provide the strongest available information: the original manufacturer, model, year, any label details and clear confirmation of the finish required. A specialist colour match may still be possible, but it is sensible to test a small inconspicuous area first.

UPVC, composite doors and foil references

UPVC windows, composite doors and fascia products are often identified by RAL shades, supplier-specific names or Renolit foil codes. A foil code is particularly useful because it may refer to a woodgrain or textured surface rather than a plain painted colour.

The key point is that the coating must be formulated for UPVC or the relevant composite surface. General-purpose paint may initially look acceptable but can struggle with adhesion, flexibility and weather exposure. For frames, doors and exterior trim, colour accuracy needs to be backed by a durable specialist formula.

Finding the correct paint code

Start with paperwork before trying to match by eye. Product invoices, installation documents, vehicle handbooks, manufacturer labels and leftover paint tins are all better sources than a phone photograph. Record the code exactly as shown, including letters, digits, spaces and suffixes.

If the code cannot be found, inspect a protected section of the item. The underside of a removable panel, an area behind a hinge, or a section covered by a trim piece may show the original colour more clearly than an exposed face. Sunlight, cleaning products, road film and weathering can shift the visible shade over time.

When supplying a digital reference, give the value and colour space. A Hex value, for example, is designed for screen colour and may not reproduce as a perfectly identical physical coating. RGB and CMYK also depend on the device or print process used. LAB values can offer a more controlled way to describe colour, but paint on a real substrate will still reflect light differently from a monitor or printed swatch.

For that reason, digital references are excellent for getting close to a brand or design colour, but they should be treated with care where an invisible repair is required.

Colour is only half the order

Once the shade is identified, choose the paint around the job. Aerosol paint needs to adhere to the material, resist the environment and produce the finish you expect. The same RAL code can be mixed into coatings intended for very different surfaces.

For example, a radiator requires a heat-resistant coating; a kitchen cupboard needs a hard-wearing furniture finish; a metal gate benefits from a coating suited to exterior metal; and a plastic window frame needs a UPVC-specific formula. Using the wrong product can lead to poor adhesion, softness, cracking or premature fading, even when the colour itself is correct.

Finish level also changes how colour is perceived. Gloss reflects more light and often makes a colour look cleaner and more intense. Matt absorbs light and can look softer or slightly lighter. Satin sits between the two and is a popular choice for many domestic and commercial surfaces. If you are repairing rather than repainting the complete item, matching the sheen is just as important as matching the code.

Texture is another consideration. A smooth aerosol finish will not fully recreate a deeply textured powder coat, woodgrain foil or aged brush-painted surface. It can still provide an effective repair or colour change, but expectations should be realistic.

Prepare and test before spraying

Even professionally blended colour will not rescue poor preparation. Clean the surface thoroughly to remove grease, polish, silicone, dust and loose material. Rub back flaking paint, key sound existing coatings where appropriate, and use a suitable primer when the substrate or repair demands it.

Before spraying the visible area, shake the can thoroughly and test it on a sample card or hidden section. This confirms the spray pattern, finish and perceived shade. Test panels are especially worthwhile for metallic vehicle colours, old paintwork and projects where several materials meet.

Apply several light, even coats rather than trying to cover in one heavy pass. Keep the can moving, maintain a consistent distance and allow appropriate flash-off time between coats. Heavy application can cause runs, uneven gloss and a darker-looking build-up in corners.

Lighting can change your judgement dramatically. Check the result in daylight where possible, then look at it under the lighting where the item will normally be seen. A grey that looks spot-on in a workshop can show a blue or green cast in a hallway or outdoors.

When a code will not guarantee an invisible repair

Paint codes are precise references, but existing surfaces change. UV exposure, heat, repeated washing and years of use can alter the original finish. On a car door, for instance, a fresh coded paint may match the factory shade yet look different beside weathered adjacent panels. On older kitchen doors, the surrounding lacquer may have yellowed.

For small touch-ups, the difference may be acceptable. For larger repairs, repainting the full panel is often the cleaner option because it removes the hard edge between new and old paint. If a finish has faded significantly, the best result may depend on blending technique, panel size and how closely the item is inspected.

Aerosols “R” Us can supply professionally mixed 400ml aerosols across recognised colour systems and specialist surface ranges, helping you specify both the colour and the coating your project needs.

Take a few extra minutes to confirm the code, substrate and finish before ordering. That small check is what turns a can of paint into a repair or refurbishment that looks planned, not patched.