What does lumen/square foot/steradian measure?

It quantifies the amount of visible light emitted or reflected per unit area per unit solid angle, expressed using US customary units.

Why convert to blondel units?

Converting to blondel helps interpret or compare luminance values reported in older photometric literature and legacy standards.

Is blondel still used in modern lighting design?

No, blondel is an obsolete unit replaced by the SI unit candela per square metre in current practice.

How to Convert from Lumen/square foot/steradian to Blondel

Learn how to convert luminance units from lumen per square foot per steradian to the historical blondel unit, useful for interpreting older photometric data.

Lumen/square foot/steradian

Blondel

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Lumen/square foot/steradian to Blondel Conversion Table

Lumen/square foot/steradian	Blondel

Custom Unit Conversion Table Generator – Instant Printable Conversion Tables

Start Value

Enter the starting number (positive decimal or integer ≥ 0). Example: 0.1, 1, 5.

End Value

Enter the ending number (positive decimal or integer > Start Value). Example: 10, 50, 100.

Interval

Enter the step size (positive decimal > 0 and < End Value – Start Value). Example: 1.0, 2.5.

Lumen/square foot/steradian to Blondel Conversion Table
Lumen/square foot/steradian	Blondel

Explore More Luminance Units Converter

What Is This Tool?

This converter allows you to translate luminance values measured in lumen per square foot per steradian into blondel, an obsolete photometric unit. It is especially helpful for working with historical lighting data and bridging US customary units with older French luminance measures.

How to Use This Tool?

Enter the luminance value in lumen/square foot/steradian.
Select the output unit as blondel.
Click convert to see the equivalent luminance in blondel.
Use the results to analyze or compare historical luminance data.

Key Features

Converts from lumen/square foot/steradian to blondel with a precise conversion factor
Supports usage in photometry, lighting design, and archival research
Helps interpret legacy photometric measurements from non-SI units
Browser-based tool for quick, accessible unit conversion

Examples

Convert 2 lumen/square foot/steradian to blondel: 2 × 33.815821889 = 67.631643778 blondel
Convert 0.5 lumen/square foot/steradian to blondel: 0.5 × 33.815821889 = 16.907910945 blondel

Common Use Cases

Specifying brightness for signs and billboards using customary US units.
Analyzing older photometric reports based on blondel luminance values.
Restoring or researching lighting projects with historical measurement data.
Comparing legacy lighting standards with modern SI units.

Tips & Best Practices

Ensure the input values use lumen/square foot/steradian units correctly.
Use this conversion mainly for historical or legacy data interpretation.
Confirm unit consistency when comparing to modern candela per square metre values.
Handle conversions carefully to maintain accuracy across unit systems.

Limitations

Blondel is an outdated unit no longer used in modern luminance measurement.
Conversion depends on consistent unit application due to different measurement systems.
Limited direct relevance for current lighting engineering practices.

Frequently Asked Questions

What does lumen/square foot/steradian measure?: It quantifies the amount of visible light emitted or reflected per unit area per unit solid angle, expressed using US customary units.
Why convert to blondel units?: Converting to blondel helps interpret or compare luminance values reported in older photometric literature and legacy standards.
Is blondel still used in modern lighting design?: No, blondel is an obsolete unit replaced by the SI unit candela per square metre in current practice.

Key Terminology

Lumen/square foot/steradian: A non-SI luminance unit measuring luminous flux per area per solid angle in US customary units.
Blondel: An obsolete luminance unit from early 20th-century photometry, replaced by candela per square metre.

Quick Knowledge Check

What type of measurement is lumen/square foot/steradian?

Electric current

Luminance

Temperature

Which unit is considered obsolete?

Lumen/square foot/steradian

Blondel

Candela per square metre

For what reason might one convert lumen/square foot/steradian to blondel?

To measure sound intensity

To interpret historical luminance data

To calculate area in square feet

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