Colour Matching Paint in London: How to Get an Exact Match

Why Colour Matching Is Harder Than It Looks

Matching an existing paint colour sounds simple. Find the closest chip in a range, mix a pot, and apply it. In practice, it is one of the more technically demanding things a decorator can be asked to do, and doing it poorly produces results that are often worse than simply repainting the whole room in a new colour.

The difficulty arises from several sources: paint fades and shifts in tone over time; different paint systems use different pigment mixes for ostensibly identical colours; the base product affects how a colour reads; and the light in which the match is assessed may be completely different from the light in which the paint will eventually be seen. Understanding the process — and its limits — will help London homeowners set realistic expectations and get better results.

The Right Tool: Spectrophotometers

A spectrophotometer is the industry-standard tool for colour matching. It works by shining a controlled light source onto the surface to be matched and measuring the wavelengths of light reflected back from the surface across the visible spectrum. This reflectance data is then processed by software to produce a mix recipe in a given paint system — typically defined in terms of the colorant concentrations to add to a specified base.

This is fundamentally more accurate than visual matching, which is subject to metamerism (the phenomenon where two colours look the same under one light source but different under another). A spectrophotometer eliminates the human eye from the measurement step, though it does not eliminate the need for human judgement in assessing the result.

Most major paint retailers — Dulux Decorating Centres, Crown Decorating Centres, Brewers, and specialist decorators' merchants — operate spectrophotometer matching services. Many carry instruments that can work directly from a surface (a painted wall, a skirting, a piece of furniture) rather than requiring a paint chip, which is particularly useful when the surface to be matched is fixed in place.

The Process: What to Expect

When you bring a surface or sample for spectrophotometric matching, the process typically works as follows:

1. The instrument reads the surface at multiple points and averages the readings to account for any surface variation or fading
2. The software identifies the closest recipe in the specified paint brand's system
3. A sample pot is mixed and applied to a test card
4. The test card is assessed against the original surface under multiple light sources (daylight, incandescent, fluorescent) to check for metamerism
5. Adjustments are made if needed before full production

The whole process at a good decorating merchant takes 20 to 30 minutes. The resulting match is typically very close — within perceptible but acceptable tolerance — though a perfect match is only possible if the original colour has not shifted significantly through fading or yellowing.

Matching Faded and Aged Surfaces

This is where colour matching becomes genuinely difficult. A colour that has been on a wall for ten years has not simply been diluted — it has changed chemically. UV light breaks down pigments at different rates depending on their molecular structure. Blue pigments (phthalocyanine blues) tend to be very lightfast; reds and yellows (certain organic pigments) can fade significantly. A faded existing colour may therefore have a quite different undertone from the original formulation.

Two approaches can help:

Match to the original specification, not the aged surface. If you know the original colour — the brand and name are often written on the tin lid or noted in a record left by the previous decorator — start by getting a fresh mix of that specification and assess it against the aged surface. The fresh colour will look brighter and more saturated, but once applied and given a year or two of light exposure, it will begin to converge with the existing surface.

Accept a visible join and repaint the whole surface. In most situations, this is the professional recommendation. Matching into an aged surface is likely to produce a patch that reads differently at different times of day, under different lights, and from different angles. Repainting the whole wall or whole room removes the variable entirely.

Historical Colours and Heritage Properties

London has an extraordinary stock of period properties — Georgian townhouses, Victorian terraces, Edwardian villas — many of which have colour schemes with historical significance or where matching an existing heritage finish is a genuine requirement.

For historical colour matching, the process goes beyond spectrophotometry. Period colours were typically made with very different pigments from modern paints — lead-based whites, earth pigments, natural ultramarine — and modern equivalents can only approximate the original effect.

Resources for historical colour research include:

• The National Archives' records of historical paint analysis
• The Society for the Protection of Ancient Buildings (SPAB) guidance notes
• Paint analysis services (available from specialist conservation laboratories) that can identify the original pigment composition from micro-samples taken from beneath later layers

Paint brands with strong heritage credentials for this work include Papers & Paints (who maintain an archive of historical formulae), Farrow & Ball (whose palette draws heavily on the Georgian and Victorian tradition), and Little Greene (whose archive collection is based on documented historical colours).

When the Original Tin Has Gone

The most common scenario is the most frustrating one: the owners moved in, there is a colour on the walls they like and want to preserve or extend, and there is no record of what it is.

Practical steps:

• Check behind light switches and socket plates, where paint is often applied but never exposed to fading or cleaning
• Look behind fixed furniture or pictures that have been in place since the house was redecorated
• Check the loft or garage for paint tins — many homeowners keep leftover paint for touch-ups
• If none of these are possible, a spectrophotometric read from an unexposed patch of the existing surface is the best starting point

Even where no exact match is achievable, a close-enough result for a whole-room repaint — where you are repainting the entire surface and the aged original will no longer be visible — is almost always possible.

Belgravia Painters offers colour matching advice and works with decorators' merchants across London to produce matched formulations for our clients. Contact us to discuss your specific colour matching requirement.