Cobalt Blue

See this colour in the real world

Colours in photographs vary with lighting, material, camera processing and screen calibration — the named colours below are visual approximations, not exact measurements.

Uses & contexts

Nearest named colours, and how they differ

• Sapphire is the closest, at ΔE00 3.9 from cobalt blue: 4 points lighter, 1 points more saturated and 1° round towards blue. That is visibly different side by side, easily confused apart.

• Persian Blue is next, at ΔE00 6.2 from cobalt blue: 2 points darker, 18 points more saturated and 8° round towards red. That is clearly different, though many people would use one name for both.

• International Klein Blue is next, at ΔE00 7.7 from cobalt blue: 7 points darker, 14 points more saturated and 8° round towards red. That is clearly different, though many people would use one name for both.

• Denim Blue is next, at ΔE00 8.5 from cobalt blue: 9 points lighter, 6 points less saturated and 7° round towards blue. That is clearly different, though many people would use one name for both.

Distances are CIEDE2000 between catalogue reference values; lightness and saturation are CIELAB L* and C*. How to read a ΔE figure · Measure any two colours

Using cobalt blue in a real space

Worked out from this colour’s own measurements — its lightness, saturation and undertone — rather than written for it. That is why the guidance differs from one colour to the next even when the two look similar.

What role it can play

This is a small-scale colour. At chroma 63 it holds attention easily, which is a strength on a cushion or a door and a liability across four walls.

• Walls and large surfaces

  difficult

  At chroma 63 this is far above the level walls and large surfaces usually carry comfortably. It can be done deliberately, but it will be the room rather than part of it.

• Secondary surfaces

  workable

  Chroma 63 is above the usual comfort level for secondary surfaces, so expect it to take charge. That is a legitimate choice in a room that wants a subject. On panelling, a chimney breast or an alcove this is semi-permanent — repaintable, but not casually.

• Furniture

  workable

  Chroma 63 is above the usual comfort level for furniture, so expect it to take charge. That is a legitimate choice in a room that wants a subject. In a sofa or a cabinet this is one purchase you will live with, so it is worth seeing the piece in the actual room first.

• Rugs, curtains and bedding

  workable

  Chroma 63 is above the usual comfort level for rugs, curtains and bedding, so expect it to take charge. That is a legitimate choice in a room that wants a subject. In rugs, curtains and bedding it is the cheapest commitment in the room to reverse, which makes it the right place to test a strong colour.

• Trim and joinery

  strong

  Chroma 63 sits inside the range trim and joinery carry without taking over the room.

• Accents and small objects

  strong

  Chroma 63 is exactly what an accent is for. The saturation that makes this difficult across a wall is the reason it works on a cushion, a door or a single chair.

How it behaves under different lightresilient

Under warm bulbs

Warm bulbs emit little short-wavelength energy, so there is less for a blue to reflect. There is enough chroma here to survive it, though it will read warmer and slightly duller.

Under cool bulbs

Cool light flatters this — it will hold its identity and may read slightly more saturated than in warm light.

In daylight

Deep colours hold their identity in daylight better than pale ones, because there is more of the range left to work in. This will look most like itself in good indirect light.

In a dim room

At low light levels the eye's colour discrimination genuinely falls and deep colours converge toward each other. This will read as "dark" rather than as its own colour in a dim room unless it is lit.

Compared with the sample card

Expect a modest step darker than the chart, which is normal and is why sampling a large area matters.

What colour temperature actually means · Why two bulbs at the same rating can differ

With wood

• Oak · Pine · Plywood · Light wood (ash, birch, beech)

  works well

  Opposite in undertone to Oak, Pine, Plywood and Light wood (ash, birch, beech), but 33–53 points apart in lightness or far enough round the hue circle that the difference reads as deliberate contrast rather than as a clash.

• Walnut · Dark wood · Reddish wood (mahogany, cherry, teak)

  needs care

  Opposed in undertone to Walnut, Dark wood and Reddish wood (mahogany, cherry, teak) with only 5–11 points of lightness to explain the difference, which is the combination the eye most often reads as an error.

The amount of timber matters as much as the tone: one piece is an accent, a floor plus joinery is the room’s dominant colour. More on working with wood tones

With metal fittings

• Chrome · Stainless steel · Black metal

  works well

  Shares the cool bias of Chrome, Stainless steel and Black metal, so they agree about the temperature of the room, and 26–48 points of lightness keep them readable as separate from this colour.

• Brass · Gold-tone · Copper

  needs care

  Shares the cool bias of Brass, Gold-tone and Copper, but at chroma 63 against materials that carry colour of their own, the two compete rather than combine. It works when this colour is confined to a small area and fails when both are large.

Metal carries more attention than its area suggests, so repetition matters more than the exact finish. More on metals and mixing them

Where it can go wrong

• May dominate a small or dim room. At L*33 and chroma 63 it absorbs light and holds attention at the same time, which is a lot to ask of a space that has little of either.

Lighter, darker & directional variants

Calculated directional adjustments. Some directions converge on the same result from this starting colour — shown as one merged card with an explanation, not repeated duplicates. Generated shades link to a curated profile only when one is close enough.

In nature