| Quantity | Unit | Dimension [nb 1] |
Notes | ||
|---|---|---|---|---|---|
| Name | Symbol[nb 2] | Name | Symbol | ||
| Luminous energy | Qv[nb 3] | lumen second | lm⋅s | T⋅J | The lumen second is sometimes called the talbot. |
| Luminous flux, luminous power | Φv[nb 3] | lumen (= candela steradian) | lm (= cd⋅sr) | J | Luminous energy per unit time |
| Luminous intensity | Iv | candela (= lumen per steradian) | cd (= lm/sr) | J | Luminous flux per unit solid angle |
| Luminance | Lv | candela per square metre | cd/m2 (= lm/(sr⋅m2)) | L−2⋅J | Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit. |
| Illuminance | Ev | lux (= lumen per square metre) | lx (= lm/m2) | L−2⋅J | Luminous flux incident on a surface |
| Luminous exitance, luminous emittance | Mv | lumen per square metre | lm/m2 | L−2⋅J | Luminous flux emitted from a surface |
| Luminous exposure | Hv | lux second | lx⋅s | L−2⋅T⋅J | Time-integrated illuminance |
| Luminous energy density | ωv | lumen second per cubic metre | lm⋅s/m3 | L−3⋅T⋅J | |
| Luminous efficacy (of radiation) | K | lumen per watt | lm/W | M−1⋅L−2⋅T3⋅J | Ratio of luminous flux to radiant flux |
| Luminous efficacy (of a source) | η[nb 3] | lumen per watt | lm/W | M−1⋅L−2⋅T3⋅J | Ratio of luminous flux to power consumption |
| Luminous efficiency, luminous coefficient | V | 1 | Luminous efficacy normalized by the maximum possible efficacy | ||
| See also: | |||||
- ^ The symbols in this column denote dimensions; "L", "T" and "J" are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
- ^ Standards organizations recommend that photometric quantities be denoted with a subscript "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
- ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.
Usage
[edit]This template displays a table of SI photometry units for usage in articles about photometry. It may also serve as a navigation box at the end of corresponding articles.
The template supports three optional parameters to finetune its behaviour.
Parameters
[edit]Documentation of parameters:
Parameter 1
[edit]1 = undefined or empty
The template will not display the string "Table X. " in front of the table's title "SI photometry units".
1 = <number>
The template will display the table number as part of the table header in the following form: "Table <number>. SI photometry units.", where <number> is a placeholder for the number (or other table designation) given as parameter.
Parameter 2
[edit]2 = undefined or empty
The template will not show a "(Compare)" link in the table footer.
2 = "self"
The template will display a "(Compare) link in the table footer to jump to the corresponding radiometry table within the same article for quick comparisons. In order for this to work, the radiometry table must be included using the template {{SI radiometry units}} as well. It is not necessary to reload the article for comparison.
2 = any non-empty string other than "self"
The template will display a "(Compare)" link (as above). However, the link will point to the corresponding radiometry table in the separate article on "Radiometry", not to within the article, where the {{SI light units}} template has been included. This is useful, if the other table should not be included in the article.
Parameter 3
[edit]3 = undefined
The table's footnotes will be grouped in a reference group named "nb" and displayed immediately after the table. In order to avoid conflicts with other references in the article, it is advisable to use other group names for external references (default is ""). Otherwise, these external references would be listed after the table as well.
3 = empty, that is: ""
The table's footnotes will be grouped in the article's default group "", as used for all other references without specific group names. It is important to manually include a <references/> tag or the {{Reflist}} template somewhere in the article. This is the place where the footnotes will show up.
3 = <groupname>
The table's footnotes will be grouped in a reference group named as specified in the groupname. It is important to manually include a <references group="<groupname>"/> tag or the {{Reflist|group=<groupname>}} template somewhere in the article. This is the place where the footnotes will show up. Try to use a short groupname, as the table will look nicer this way.
Examples
[edit]Some easy examples:
{{SI light units}}
{{SI light units|1}}
{{SI light units|1|compare}}
{{SI light units||compare}}
{{SI light units|1|compare|""}}
{{SI light units|1||""}}
{{SI light units||compare|""}}
{{SI light units|1|compare|Note}}
{{SI light units|||notes}}
{{SI light units||compare|Note}}
Combining both tables in a single article (individually grouped footnotes in group "nb"):
{{SI light units|1|self}}
{{SI radiometry units|2|self}}
Combining both tables in a single article (individual footnotes in separately named groups, for example "T1" and "T2"):
{{SI light units|1|self|T1}}
{{Reflist|group=T1}}
{{SI radiometry units|2|self|T2}}
{{Reflist|group=T2}}
Combining both tables in a single article (combined footnotes, for example in group "nb"):
{{SI light units|1|self|nb}}
{{SI radiometry units|2|self|nb}}
...
{{Reflist|group=nb}}
Combining both tables in a single article (combined footnotes with default references):
{{SI light units|1|self|""}}
{{SI radiometry units|2|self|""}}
...
{{Reflist}}
Notes
[edit]Ideally, the "(Compare)" link would show up to the left or right of the table header, similar to the "v d e" links. Thereby, the cursor would remain in the same position and one could flip back and forth between the two tables without any necessary window realignment. However, this would require a small change in the {{Tnavbar-header}} template.
See also
[edit]