Short answer
Shops light merchandise brightly and directionally, often with sources chosen to make colours look vivid rather than exactly true. Lighting standards recognise this: TM-30's specification guidance lists retail among applications for a 'preference' intent and display among those for a 'vividness' intent. The same choices that sell a product can mislead a buyer comparing it with things at home.
Most shops combine general lighting that lets people move and see, accent lighting — spotlights several times brighter than the surroundings — that pulls the eye to displays, and task or verification lighting at counters, mirrors and fitting rooms. Each layer can use a different source. The contrast between bright displays and dimmer aisles makes products look more colourful than they would in even light, because perceived colourfulness rises with luminance and with the brightness of an object relative to its surround.
TM-30 Annex E asks specifiers to pick a design intent before a number. Preference aims at a pleasing, natural look, and is named for retail, hospitality, offices and homes; its criteria set upper as well as lower limits on red chroma shift, allowing a modest boost to reds. Vividness aims at a vibrant scene whether or not it is natural, and is named for display, entertainment and some retail. Fidelity aims at matching the reference, for colour-critical work. A fashion or furniture retailer typically chooses Preference; a food counter or a showroom may push towards Vividness. Programmes such as the DesignLights Consortium have adopted TM-30 Preference criteria for qualifying products.
Food retail often favours spectra that deepen reds and warm yellows, so meat, tomatoes and baked goods look ripe and rich. Fashion wants skin in fitting rooms to look healthy, which again means good deep-red rendering, and increasingly a light close to daylight for checking. Paint and décor retailers face the hardest problem, because customers are trying to predict colour in their own homes; good practice here is a daylight-like, high-fidelity viewing area separate from the flattering shop floor. Cosmetics counters need high fidelity at the mirror above all.
Vivid light is legitimate display, but it makes returns more likely when customers match purchases to things at home. Three remedies are cheap: a verification point with high-fidelity, daylight-like light near the till or fitting rooms; windows or doors where customers can see goods in daylight; and staff who expect and allow comparison with samples brought from home. For the customer's side of the same problem — why a match made in the shop fails at home — see the site's matching page.
| Intent | Aim | Typical retail use |
|---|---|---|
| Preference | Pleasing, natural-looking colour | General floor of fashion, homeware and hospitality |
| Vividness | Vibrant colour, natural or not | Feature displays, food counters, showrooms |
| Fidelity | Appearance close to the reference | Colour-check points, paint and cosmetics counters |
Why: Vivid floor lighting and metamerism between product and customers' existing items.
Fix: Add a high-fidelity colour-check point and encourage comparison with brought-in samples.
Why: Replacement lamps chosen on Ra and efficacy have weak deep red (negative red chroma shift).
Fix: Specify TM-30 red chroma shift near zero or positive for food areas.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
StandardStrong evidence
TM-30 Annex E names retail among applications where colour Preference may be the dominant design intent, and display and some retail among those where colour Vividness may be.
StandardStrong evidence
The Preference criteria in TM-30 Annex E set both lower and upper limits on red chroma shift (Rcs,h1), allowing a controlled boost to reds.
ConventionModerate evidence
The DesignLights Consortium's technical requirements (version 5.1) use the TM-30 P3 Preference specification for indoor products other than high-bay.
Caveat: As reported in 2022; the programme's current version may differ.
Colourwise interpretationLimited evidence
Retailers selling products that customers must match at home reduce mismatches by providing a separate high-fidelity viewing point rather than lighting the whole floor for fidelity.
Based on: Follows from the distinct Preference, Vividness and Fidelity intents and the evidence that light level and spectrum change appearance; not a measured study of returns.
Caveat: Colourwise's recommendation, not an industry standard.
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.