candelas per square metre (cd/m2) to stilbs (sb) conversion

1 cd/m2 = 0.0001 sbsb → cd/m2
Formula
1 cd/m2 = 0.0001 sb

Understanding Candelas per square metre to Stilbs Conversion

The candela per square metre (cd/m2), also called the nit, is the SI unit of luminance and describes how much luminous intensity a surface emits or reflects per unit area. The stilb (sb) is the CGS unit of luminance, defined as one candela per square centimetre. Because a square metre contains 10,000 square centimetres, one stilb represents a far brighter surface than one nit, which is why the stilb survives mostly in older photometry and optics literature.

Conversion Formula

1 cd/m2=0.0001 sb1\ \text{cd/m2} = 0.0001\ \text{sb}

To convert candelas per square metre to stilbs, multiply by this factor:

sb=cd/m2×0.0001\text{sb} = \text{cd/m2} \times 0.0001

Step-by-Step Example

Convert 25 candelas per square metre to stilbs.

sb=25×0.0001=0.0025 sb\text{sb} = 25 \times 0.0001 = 0.0025\ \text{sb}

How to Convert Candelas per square metre to Stilbs

Convert any candelas per square metre value into stilbs in three quick steps.

  1. Identify the luminance in cd/m2: Start with the surface luminance expressed in candelas per square metre (nits).
  2. Apply the factor: Multiply by 0.0001, because one stilb equals 10,000 cd/m2.
  3. Read the result in stilbs: The product is the equivalent luminance in stilbs.

For example, 25 candelas per square metre equals 0.0025 sb.

candelas per square metre to stilbs conversion table

candelas per square metre (cd/m2)stilbs (sb)
00
10.0001
20.0002
30.0003
40.0004
50.0005
60.0006
70.0007
80.0008
90.0009
100.001
150.0015
200.002
250.0025
300.003
400.004
500.005
600.006
700.007
800.008
900.009
1000.01
1500.015
2000.02
2500.025
3000.03
4000.04
5000.05
6000.06
7000.07
8000.08
9000.09
10000.1
20000.2
30000.3
40000.4
50000.5
100001
250002.5
500005
10000010
25000025
50000050
1000000100

What is the candela per square metre?

The candela per square metre is the SI unit of luminance, measuring the luminous intensity emitted or reflected from a surface per unit area in a given direction. It describes how bright a surface appears to the human eye and is the standard used to specify display and screen brightness.

Definition

Luminance is luminous intensity per unit projected area. One candela per square metre is the luminance of a surface emitting one candela of luminous intensity from each square metre of its projected area.

1 cd/m2=1 cd/m21\ \text{cd/m}^2 = 1\ \text{cd/m}^2

As a derived SI unit it can be written 1 cd/m2=1 lm/(m2⋅sr)1\ \text{cd/m}^2 = 1\ \text{lm}/(\text{m}^2 \cdot \text{sr}), since the candela equals one lumen per steradian.

Origin and History

The candela became one of the seven SI base units in 1948 (as the "new candle"), and luminance in candela per square metre followed as the coherent derived unit. It replaced a patchwork of earlier photometric units such as the stilb, lambert, and foot-lambert.

Law and Notable Facts

The candela per square metre is the internationally sanctioned SI unit of luminance and is colloquially known as the "nit." Its value ties to the modern definition of the candela, fixed by the luminous efficacy of monochromatic 540 THz radiation at 683 lm/W.

Real-World Examples and Conversions

  • A typical computer monitor: 200–350 cd/m².
  • A smartphone in bright sunlight mode: 800–2000 cd/m².
  • Clear daytime sky: several thousand cd/m².
  • 1 cd/m2=1 nit=10−4 stilb1\ \text{cd/m}^2 = 1\ \text{nit} = 10⁻⁴\ \text{stilb}.

What is the stilb?

The stilb is a CGS unit of luminance, describing the brightness of a surface in terms of luminous intensity per unit area. It was widely used in older photometric literature before the SI candela per square metre became standard.

Definition

One stilb is one candela per square centimetre. Since there are ten thousand square centimetres in a square metre, the stilb is a large unit relative to the SI luminance unit.

1 sb=10000 cd/m21\ \text{sb} = 10000\ \text{cd/m}^2

Exactly, 1 sb=1 cd/cm2=104 cd/m2=104 nits1\ \text{sb} = 1\ \text{cd/cm}^2 = 10⁴\ \text{cd/m}^2 = 10⁴\ \text{nits}.

Origin and History

The stilb was introduced by the French physicist André Blondel around 1920, its name taken from the Greek stilbein, "to glitter." It belonged to the centimetre–gram–second system and was used chiefly in continental Europe.

Law and Notable Facts

The stilb is not part of the SI and has largely fallen out of use in favour of the candela per square metre. Because it references the square centimetre, a single stilb represents a very bright surface: the sun's disc at the horizon is on the order of a few hundred stilbs.

Real-World Examples and Conversions

  • A frosted incandescent lamp surface: a few stilbs.
  • The sun's disc viewed from Earth: roughly 160,000 cd/m², or about 16 stilbs.
  • 1 sb=104 cd/m2=104 nits1\ \text{sb} = 10⁴\ \text{cd/m}^2 = 10⁴\ \text{nits}.
  • 1 cd/m2=10−4 sb1\ \text{cd/m}^2 = 10⁻⁴\ \text{sb}.

Frequently Asked Questions

Is a nit the same as a candela per square metre?

Yes. The nit is simply an informal name for the candela per square metre, so 1 nit equals 1 cd/m2 and both convert to stilbs identically.

Why is the stilb so much larger than the candela per square metre?

The stilb is candelas per square centimetre while the nit is candelas per square metre, and one square metre holds 10,000 square centimetres, so 1 sb equals 10,000 cd/m2.

How many stilbs is a typical laptop screen?

A laptop displaying around 300 cd/m2 emits only 0.03 sb, showing how small everyday luminance values look on the stilb scale.

Where is the stilb still used?

It appears in older optics, astronomy, and photometry texts, so this conversion is mainly needed when interpreting historical brightness data in modern units.

People also convert

cd/m2 to ntcd/m2 to asbcd/m2 to Lcd/m2 to fL

Complete candelas per square metre conversion table

cd/m2
UnitResult
nits (nt)1 nt
stilbs (sb)0.0001 sb
apostilbs (asb)3.141593 asb
lamberts (L)0.0003141593 L
foot-lamberts (fL)0.2918635 fL

Luminance conversions