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

1 sb = 10000 cd/m2cd/m2 → sb
Formula
1 sb = 10000 cd/m2

Understanding Stilbs to Candelas per Square Metre Conversion

The stilb (sb) is a CGS luminance unit equal to one candela per square centimeter. The candela per square metre (cd/m², also called the nit) is the SI unit of luminance and the standard specification for display brightness, signage, and lighting design. Converting stilbs to cd/m² is simply a change of area basis from square centimeters to square meters, a factor of 10,000.

Conversion Formula

1 sb=10000 cd/m21\ \text{sb} = 10000\ \text{cd/m2}

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

cd/m2=sb×10000\text{cd/m2} = \text{sb} \times 10000

Step-by-Step Example

Convert 25 stilbs to candelas per square metre.

cd/m2=25×10000=250000 cd/m2\text{cd/m2} = 25 \times 10000 = 250000\ \text{cd/m2}

How to Convert Stilbs to Candelas per Square Metre

Rebase a CGS luminance onto the SI unit used for display brightness.

  1. Take the stilb value: For example, 25 sb.
  2. Multiply by 10000: This accounts for the cm²-to-m² area change.
  3. Compute: 25×10000=25000025 \times 10000 = 250000.
  4. State the result: 25 stilbs equals 250,000 cd/m².

stilbs to candelas per square metre conversion table

stilbs (sb)candelas per square metre (cd/m2)
00
110000
220000
330000
440000
550000
660000
770000
880000
990000
10100000
15150000
20200000
25250000
30300000
40400000
50500000
60600000
70700000
80800000
90900000
1001000000
1501500000
2002000000
2502500000
3003000000
4004000000
5005000000
6006000000
7007000000
8008000000
9009000000
100010000000
200020000000
300030000000
400040000000
500050000000
10000100000000
25000250000000
50000500000000
1000001000000000
2500002500000000
5000005000000000
100000010000000000

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}.

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}.

Frequently Asked Questions

How many candelas per square metre equal one stilb?

One stilb equals 10,000 cd/m², because there are 10,000 square centimeters in a square meter.

How do I convert cd/m² back to stilbs?

Multiply the cd/m² value by 0.0001, or divide by 10,000. So 10,000 cd/m² equals 1 sb.

Is cd/m² the same as a nit?

Yes. One candela per square metre is exactly one nit, the unit used for display and screen brightness.

Why is the SI unit preferred over the stilb?

The candela per square metre integrates cleanly with SI photometry and is the industry standard for displays, so the CGS stilb is now rarely used.

What is 0.5 stilb in cd/m²?

Multiply 0.5 by 10,000 to get 5,000 cd/m².

People also convert

sb to ntsb to asbsb to Lsb to fL

Complete stilbs conversion table

sb
UnitResult
candelas per square metre (cd/m2)10000 cd/m2
nits (nt)10000 nt
apostilbs (asb)31415.93 asb
lamberts (L)3.141593 L
foot-lamberts (fL)2918.635 fL

Luminance conversions