How paint colour matching works here

Three separate things get presented as one on most colour sites: what the manufacturer published, what somebody calculated, and what somebody thinks. This page keeps them apart, explains what each is worth, and sets out why Colourwise publishes no manufacturer paint catalogue.

The four labels

Every value on a Colourwise paint page carries one of these. They are attached per field, not per page — a paint whose name comes from the manufacturer and whose CIELAB value Colourwise computed is an ordinary case, and both halves are labelled separately.

Manufacturer-published: The manufacturer publishes this value themselves. Colourwise reproduces it without alteration and cites where it came from.
Derived from manufacturer-published value: Colourwise calculated this from a value the manufacturer published — a HEX code converted from their own RGB, for instance. The arithmetic is exact, but the manufacturer did not state this form of it.
Colourwise-derived: Computed by the Colourwise colour engine from a value it holds. Deterministic and reproducible, but it is our measurement of the digital colour, not the manufacturer's statement about the paint.
Colourwise guidance: Colourwise's own practical judgement. Useful, arguable, and not a fact about the product.
Approximate digital representation: An approximation with no manufacturer-published value behind it. Treat it as an indication of roughly which colour is meant, never as a specification.

The distinction that matters most is between the first two. A HEX code converted from a manufacturer’s own published RGB is exact arithmetic on an official number — and it is still not an official number, because the manufacturer never published it in that form. Colourwise will not invent an official HEX where none exists, and where no manufacturer value exists at all, it publishes nothing rather than a sampled approximation.

LRV, and the thing that is not LRV

Light Reflectance Value is the percentage of visible light a painted surface reflects, measured off a physical sample with an instrument. It is the single most useful number a paint manufacturer publishes, because it predicts what a colour will do to the light level in a room better than any description does.

It cannot be calculated from a digital colour, and Colourwise does not pretend otherwise. What can be computed is relative luminance — a 0-100 figure derived from sRGB. This is relative luminance computed from a digital colour, not a Light Reflectance Value. LRV is measured off a physical painted surface with an instrument; the two correlate but they are different quantities, and a digital figure cannot substitute for a manufacturer's measurement.

So when Colourwise shows a luminance figure it is labelled relative luminance, and when you need an actual LRV it sends you to the manufacturer. The brands that publish it are listed on the paint hub.

How similarity is calculated

Perceptual distance uses CIEDE2000 on CIELAB values, which is the standard the industry settled on because simple Euclidean distance in RGB does not track how different two colours actually look. Alongside it, each result reports the lightness, chroma and hue differences separately, because a single distance figure hides which of the three moved.

There is no percentage score, deliberately. A “92% match” implies a scale, a scale implies a defined methodology, and no such definition exists in this field. A sentence saying the candidate is slightly deeper, a little greyer and shifted warmer tells you more and claims less.

The nine goals

As close as possible: Minimises the total perceptual difference. The right question when you want the nearest thing available and are not trying to change anything.
The same idea, lighter: Holds the hue and the saturation and moves the lightness up. Use this when a colour is right but the room cannot afford how much light it absorbs.
The same idea, deeper: Holds the hue and the saturation and moves the lightness down. Use this when a colour is right but reads as too weak on a large surface.
The same idea, warmer: Holds the lightness and the depth and shifts the undertone towards yellow and red. Use this when a colour goes cold under the light you actually have.
The same idea, cooler: Holds the lightness and the depth and shifts the undertone towards blue and green. Use this when a colour reads yellow or pink in a way you did not want.
The same idea, less saturated: Holds the hue and the lightness and takes saturation out. Use this when a colour is the right idea but too loud across a whole wall.
The same idea, more saturated: Holds the hue and the lightness and puts saturation in. Use this when a colour disappears in place and needs to actually register.
A different colour at the same lightness: Ignores hue entirely and matches how light the colour is. This is the useful one for substituting inside an existing scheme, because lightness is what sets a room's structure.
A different colour with the same undertone: Ignores hue family and matches warmth. Undertone is what governs whether a colour sits comfortably beside a given wood or metal.

Why nothing here is an “exact equivalent”

A close digital match is not an equivalent paint. Two coatings that measure alike on screen can differ in formulation, sheen, opacity and the way they reflect a particular light source — so they can agree under one lamp and diverge under another. Nothing here is an exact equivalent unless the manufacturer says so themselves.

Concretely: two coatings with the same measured colour can carry different pigment loads, which changes how they behave under a light source with an uneven spectrum. They can have different sheens, which changes how much specular reflection reaches the eye and therefore how deep the colour reads. And they can be metameric — agreeing under one illuminant and diverging under another. None of that is visible in a hex code.

Colourwise therefore describes results as similar, close, perceptually similar, or the closest candidate available. It reserves the word equivalent for cases where a manufacturer has said so themselves.

Why there is no manufacturer catalogue

Twelve manufacturers were assessed on 2026-08-22: their robots.txt, their published terms of use, what each displays publicly, and whether any offers data for reuse. 12 of 12 are blocked, and the remaining position is reference-only. No manufacturer field is cleared for storage.

The recurring pattern is that a colour value being visible on a public page is not permission to republish it. Several brands prohibit automated extraction by name; most restrict site content to personal, non-commercial use; several assert database rights over the catalogue as a compilation. A permissive robots.txt alongside restrictive terms — which is common — means the terms govern.

Data-rights position for twelve paint manufacturers
Brand	robots.txt	Terms permit commercial reuse	Verdict
Farrow & Ball	Restrictive	Unclear	Reference only
Dulux	Permissive	No	Blocked
Dulux Heritage	Permissive	No	Blocked
Little Greene	Unreadable — bot barrier	No	Blocked
Crown Paints	Permissive	No	Blocked
Valspar	Permissive	No	Blocked
Lick	Permissive	No	Blocked
Benjamin Moore	Restrictive	No	Blocked
Sherwin-Williams	Restrictive	No	Blocked
Behr	Unreadable — bot barrier	No	Blocked
PPG Paints	Permissive	No	Blocked
Glidden	Permissive	Unclear	Blocked

What each classification means

Safe to store: May be stored and republished with provenance and attribution. Currently applies to no manufacturer field.
Safe to derive: Colourwise may compute its own equivalent from a value it lawfully holds, but may not store the manufacturer's.
Link or reference only: The brand and its colours may be named and linked to; the values may not be reproduced.
Do not ingest without permission: The manufacturer's terms forbid the use Colourwise would make of it.
Unclear — manual review: Not established either way — treated exactly like a refusal, because a field nobody has checked carries the same risk as one that has been forbidden.

The fields assessed

Colour name
Colour code or number
Collection membership
RGB value
HEX value
Light Reflectance Value
Colour family
Undertone description
Finish availability
Surface and room recommendations
The catalogue as a whole

When a paint would get its own page

If a licence ever arrives, a record existing will still not be a reason to publish it. A paint profile has to clear every one of these before it becomes indexable, and a record that fails any of them is held back rather than published thin.

The brand has no entry in the data-rights register, so nothing about it has been cleared.
No field on this record clears the rights gate, so there is nothing publishable to build a page from.
The record holds neither a usable digital value nor substantive official descriptors, so a page could only restate its name.
No manufacturer page to verify against, which makes every claim unverifiable.
Without a digital value the engine can derive no room roles, lighting behaviour or material pairings, so the page would carry no practical content.
No alternatives or comparisons could be generated, leaving the page with nothing a reader could act on.
Another record covers the same colour, and two pages competing for one query serve neither.
At least one displayed value cannot say where it came from.

Brands assessed

Manufacturer and product names are used here only to identify each company's own products. Colourwise is independent: it is not affiliated with, endorsed by, approved by or connected to any paint manufacturer, and holds no manufacturer colour data under licence. All trade marks belong to their respective owners.