The interior design guide

Open Rayon

All sections

Knowledge

2Running a project

Survey
Programming
Concept design
Design development
Pricing
Documentation
Supervision

Flooring by room
Colour: undertone, LRV, light
Paint sheen by surface
Stone and tile
Joinery materials
Junctions and transitions

4Space planning

Zoning an open plan
Circulation and clearances
Furniture layouts that work
Doors, swings and openings
Testing a plan at 1:50
Planning a small flat

Sofa scale and depth
Rug sizing
Dining table and pendant
Beds and bedsides
Vintage, new or custom
Reusing what the client owns

The socket plan
Switches, circuits and scenes
Ceiling spots: grid or wall wash
Floor sockets for floating furniture
Kitchen and bathroom circuits
Data, TV and charging points

Where the soil stack sets the plan
Supply, waste and fall
Kitchen sink and appliances
Bathroom layout around the WC
Showers: valves, trays and wet rooms
Heating: radiators or underfloor

8Joinery & millwork

Kitchen carcasses and fronts
Wardrobes and alcove storage
Shelving that doesn’t sag
Skirtings, architraves and panelling
Doors, hinges and handles
Drawing joinery for the maker

Door schedules: sizes, swings and hardware
Window schedules: glazing, sills and heads
Openings without doors
Ironmongery and handles
Thresholds and level access
Fire, acoustic and privacy ratings

Art: size, height, grouping
Curtains: height, width, fullness
Lamps as objects
Shelves and objects
Plants
Knowing when to stop

Materials and finishes for a render
Daylight, evening and artificial light
Ambient occlusion and contact shadows
Camera height and lens
Styling a render
From render to client sign-off

Others

Lexicon FAQ MCP About

Metamerism.

What it means in interior design.

Metamerism is when two colours match under one light and differ under another. It happens because the materials reflect different mixes of wavelengths.

In practice

Approve paint, fabric and stone together under the room’s own light, by day and at night, never only in a showroom. It is the hidden reason the sofa matched the sample but not the curtains.

Where the guide uses it

Defined here, in the Lexicon.

Related terms.

More from Surfaces.

Undertone

An undertone is the underlying hue inside a colour, such as the green in a grey or the pink in a beige. It hides on its own and shows up next to other colours or as the light changes.

LRV

LRV (light reflectance value) is the share of visible light a colour reflects, from 0 for black to about 100 for pure white. Most paint makers print it on the chip.

Sheen

Sheen is how much light a finish reflects, from flat matt through eggshell and satin to gloss. Higher sheen is tougher and easier to wipe, but shows every flaw in the surface.

Colour drenching

Colour drenching is painting walls, trim, doors and often the ceiling in one colour. Edges and junctions disappear, so the room reads as one volume.

Junction

A junction is where two materials or planes meet: floor to wall, wall to ceiling, tile to timber. It is where workmanship shows, and where most perceived quality is decided.

Shadow gap

A shadow gap is a small recessed reveal, often around 10 mm, left between two planes instead of a direct joint. It reads as a crisp dark line and hides small imperfections.

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