CINXE.COM

<html> <head><script type="text/javascript" src="https://web-static.archive.org/_static/js/bundle-playback.js?v=7YQSqjSh" charset="utf-8"></script> <script type="text/javascript" src="https://web-static.archive.org/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script> <script>window.RufflePlayer=window.RufflePlayer||{};window.RufflePlayer.config={"autoplay":"on","unmuteOverlay":"hidden"};</script> <script type="text/javascript" src="https://web-static.archive.org/_static/js/ruffle/ruffle.js"></script> <script type="text/javascript"> __wm.init("https://web.archive.org/web"); __wm.wombat("https://www.bipm.org/metrology/photometry-radiometry/","20200531035549","https://web.archive.org/","web","https://web-static.archive.org/_static/", "1590897349"); </script> <link rel="stylesheet" type="text/css" href="https://web-static.archive.org/_static/css/banner-styles.css?v=p7PEIJWi" /> <link rel="stylesheet" type="text/css" href="https://web-static.archive.org/_static/css/iconochive.css?v=3PDvdIFv" />  <meta http-equiv="X-UA-Compatible" content="IE=8"/> <title>BIPM - photometry and radiometry</title> <meta name="description" content="Photometry and Radiometry"> <script language="javascript" src="/web/20200531035549js_/https://www.bipm.org/utils/onLoad.js"> </script> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//web.archive.org/web/20200531035549/https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-38070491-1', 'auto'); ga('send', 'pageview'); </script> <script src="/web/20200531035549js_/https://www.bipm.org/utils/jquery/jquery-1.10.2.min.js"></script> <script src="/web/20200531035549js_/https://www.bipm.org/utils/jquery/jquery-ui-1.10.3.custom/js/jquery-ui-1.10.3.custom.js"></script> <script src="/web/20200531035549js_/https://www.bipm.org/utils/zee/unslider.min.js"></script> <script src="/web/20200531035549js_/https://www.bipm.org/utils/zee/slider.js"></script> <script src="/web/20200531035549js_/https://www.bipm.org/utils/zee/cookie.js"></script> <link rel="stylesheet" href="/web/20200531035549cs_/https://www.bipm.org/utils/jquery/jquery-ui-1.10.3.custom/css/smoothness/jquery-ui-1.10.3.custom.css"> <link rel="stylesheet" href="/web/20200531035549cs_/https://www.bipm.org/resources/demos/style.css"> <link rel="stylesheet" href="/web/20200531035549cs_/https://www.bipm.org/utils/typoZEE.css" type="text/css"> </head> <body bgcolor="#FFFFFF" leftmargin="0" rightmargin="0" topmargin="0" marginwidth="0" marginheight="0">  <a name="haut">  <center> <table width="1000" cellspacing="0" cellpadding="2" border="0"> <tr> <td width="10"></td><td width="180"></td><td width="530"></td><td width="270"></td><td width="10"></td></tr> <tr height="90"> <td width="10"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10" height="90"></td> <td width="180" valign="center" align="left"><a href="/web/20200531035549/https://www.bipm.org/en/about-us/" title="BIPM home page"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/logoBIPM-RB.jpg" border="0"></a></td> <td width="530" valign="center" align="center" class="intro">    the intergovernmental organization through which Member States act together<br>      on matters related to measurement science and measurement standards.</td> <td width="270" align="center" valign="top"> <script language="javascript"> function ActionForm(f) { f.q.style.background = "white"; } </script> <form name="search" action="https://web.archive.org/web/20200531035549/https://search.bipm.org/bipm/en/C="> <table width="180" align="right" valign="top" border="0"> <tr height="50"> <td valign="bottom" class="intro">Search facility: <input onclick="ActionForm(this.form)" style="vertical-align: middle;background-image:url(/web/20200531035549im_/https://www.bipm.org/utils/en/img/bipm_portal.gif); background-repeat:no-repeat; background-position:center right;" type="text" name="q" size="25" maxlength="50"> <input type="hidden" name="action" value="s"> <input type="hidden" name="setcontext" value=""> </td> <td height="25" colspan="2" width="50" valign="bottom" align="left"><input type="image" src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/exalead.gif" border="0"></td> </tr> </table> </form> <br> <br> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="270" height="15" border="0"> <nobr><a href="/web/20200531035549/https://www.bipm.org/en/about-us/"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/home.png" border="0"></a> | <a class="navigation" href="/web/20200531035549/https://www.bipm.org/en/about-us/map.html">Site map</a> | <a class="navigation" href="/web/20200531035549/https://www.bipm.org/en/news/">News</a> | <a class="navigation" href="javascript:hidden_email('webmaster','bipm.org','BIPM website');">Contact us</a> | [<a id="langChange" data-lang="fr" href="/web/20200531035549/https://www.bipm.org/metrologie/photometry-radiometry/" class="GrosTitreVO"> FR </a>] </nobr> </td> <td width="10"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10" height="90"></td> </tr> </table>   <table width="1000" border="0" cellspacing="0" cellpadding="0"> <tr> <td nowrap width="100%"> <style media="all" type="text/css"></style> <div class="menu"> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/" target="_self">  About us</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/role.html" target="_self">Our role and objectives</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/governance/" target="_self">Governance</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/member-states/" target="_self">Member States</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/associates/" target="_self">Associates</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/" target="_self">International System of Units (SI)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/" target="_self">International equivalence of measurements<br>(CIPM MRA)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/" target="_self">Our committees</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/" target="_self">Our work programme</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/sections/" target="_self">The BIPM staff</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/vacancies/" target="_self">Jobs and Secondments</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/procurement/" target="_self">Procurement and Sales</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/directions/" target="_self">How to get to the BIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/about-us/pavillon-de-breteuil/" target="_self">History of the Pavillon de Breteuil</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/" target="_self"> Worldwide metrology</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/" target="_self">What is metrology?</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/" target="_self">International equivalence of measurements<br>(CIPM MRA)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/metre-convention/" target="_self">The Metre Convention</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/cgpm/" target="_self">The General Conference (CGPM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cipm/" target="_self">The International Committee (CIPM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/" target="_self">CIPM Consultative Committees (CCs)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/national/" target="_self">National Metrology Institutes (NMIs)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/regional/" target="_self">Regional Metrology Organizations (RMOs)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/jc/" target="_self">Joint Committees</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/liaisons/" target="_self">BIPM liaison work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cbkt/" target="_self">BIPM Capacity Building & Knowledge Transfer Programme</a></li> <li><a href="https://web.archive.org/web/20200531035549/http://www.worldmetrologyday.org/" target="_blank">World Metrology Day</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/" target="_self"> International equivalence</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/" target="_self">What is the CIPM MRA?</a></li> <li><a href="https://web.archive.org/web/20200531035549/https://www.bipm.org/kcdb" target="_self">CIPM MRA database <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img2/logo_kcdb_pt.gif"></a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/participation/" target="_self">Participating laboratories</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/cipm-mra-documents/" target="_self">CIPM MRA documents</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/approval-process.html" target="_self">CMC approval process</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cipm-mra/logo/" target="_self">Use of the CIPM MRA logo</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/jc/jcrb/" target="_self">JCRB: Joint Committee of the RMOs and the BIPM</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/" target="_self"> SI units</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/" target="_self">The International System of Units (SI)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/" target="_self">SI Brochure</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/appendix1.html" target="_self">Decisions of the CGPM and the CIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/mises-en-pratique/" target="_self">How to realize the definitions in practice</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/base-units.html" target="_self">Unit definitions</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/prefixes.html" target="_self">SI prefixes</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/si-download-area/" target="_self">Revised SI: Download area</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/history-si/" target="_self">Brief history of the SI</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/" target="_self"> Services</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/comparisons/" target="_self">Comparisons piloted by the BIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/calibrations/" target="_self">Calibration and measurement services</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/tai/" target="_self">Timescales</a></li> <li><a href="https://web.archive.org/web/20200531035549/https://www.bipm.org/kcdb" target="_self"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img2/logo_kcdb_pt.gif" alt="KCDB" vspace="2"></a></li> <li><a href="https://web.archive.org/web/20200531035549/https://www.bipm.org/jctlm/" target="_self"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img2/logo_jctlm_pt.gif" alt="JCTLM" vspace="2"></a></li> <li><a href="https://web.archive.org/web/20200531035549/http://imrr.bipm.org/" target="_self"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img2/logo_imrr_pt.gif" alt="IMRR" vspace="2"></a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/" target="_self">SI Brochure</a></li> <li><a href="https://web.archive.org/web/20200531035549/http://iopscience.iop.org/0026-1394/" target="metrologia"><i>Metrologia</i></a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/" target="_self">Meetings</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/mises-en-pratique/standard-frequencies.html" target="_self">Recommended values of standard frequencies</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/ionizing/radionuclides/sir/" target="_self">International Reference System (SIR)</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/" target="_self"> Publications</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/" target="_self">SI Brochure</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/mises-en-pratique/" target="_self"><i>Mises en pratique</i></a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/directors-report/" target="_self">Annual Director's Report</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cipm/publications-cipm.html#ra" target="_self">Financial Report</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cipm/publications-cipm.html#no" target="_self">Notification of Contributions</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/" target="_self">Official proceedings</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/cgpm/resolutions.html" target="_self">Resolutions of the General Conference</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/open-literature/" target="_self">Scientific output</a></li> <li><a href="https://web.archive.org/web/20200531035549/http://iopscience.iop.org/0026-1394/" target="metrologia"><i>Metrologia</i></a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/guides/" target="_self">Guides in Metrology</a></li> </ul> </li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/diary/" target="_self"> Meetings</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/diary/" target="_self">List of meetings</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/" target="_self">BIPM Conference Centre</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/directions/" target="_self">How to get to the BIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/cgpm-2018/" target="_self">General Conference (CGPM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cipm/" target="_self">International Committee (CIPM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/" target="_self">Consultative Committees and Working Groups</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/bipm-workshops/" target="_self">BIPM Workshops</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/other-events/" target="_self">Other BIPM events</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/" target="_self">Meeting reports</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/metrology-events.html" target="_self">External events</a></li> </ul> </li> </ul> </div> </td> </tr> </table>   <center> <table width="1000" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="10" height="50"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10" height="50"></td> <td align="left" width="100%" height="50" background="/web/20200531035549im_/https://www.bipm.org/utils/common/img/cadre_trait.gif"> <table width="100%" border="0" background="/web/20200531035549im_/https://www.bipm.org/metrology/photometry-radiometry/"> <tr> <td align="left" class="GrosTitre"><div name="exalead-titre">International metrology in the field of Photometry and Radiometry</div></td> <td align="right" nowrap>        </td> </tr> </table> </td> <td width="10" height="50"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10" height="50"></td> </tr> </table> </center>  <script> $(function() { $( "#tabs2" ).tabs(); }); </script>  <center> <table width="1000" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="10"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10"></td> <td valign="top" width="100%"> <div id="tabs2"> <ul> <li><a href="#introduction">Overview</a></li> <li><a href="#units"><a href="units.html">Units</a></a></li> <li><a href="#committees"><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccpr/">Committee structure</a></a></li> <li><a href="#strategy"><a href="/web/20200531035549/https://www.bipm.org/utils/en/pdf/CCPR-strategy-document.pdf">Strategic plan</a></a></li> </ul> <div id="introduction"> <table width="100%" cellpadding="15"><tr><td> <center> <table width="580" bgcolor="#829EBA" cellpadding="20" cellspacing="3" border="0"><tr bgcolor="#FFFFFF"><td> <p><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/fleche_jaune.gif" width="29" height="14" alt=""><b>Radiometry</b> is the field of metrology related to the physical measurement of the properties of electromagnetic radiation, including visible light.</p> <p><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/fleche_jaune.gif" width="29" height="14" alt=""><b>Photometry</b> describes the effects of visible light on the human eye, in terms of brightness and colour.</p> <p>The two fields and their units are closely related through the current definition of the <a href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/units.html" class="introGras">SI base unit for the photometric quantity luminous intensity: the candela</a>. The candela is the only SI base unit related to a fundamental biological process: human vision.</p> </td></tr></table> </center> <p>Radiometric and photometric measurements are of importance for a wide range of industries and applications, including the lighting, space, semiconductor, photovoltaic, optical communication, automotive and colour industries, displays and imaging, and climate change. Other emerging fields include appearance, terahertz applications, photonics, and quantum-based information.</p> <p>Traditionally, metrology in both radiometry and photometry is based on primary radiation detectors (cryogenic radiometers) and on primary radiation sources (blackbody radiators, electron synchrotrons). Recent advances in the manipulation of individual photons show great promise of producing within a couple of years radiant fluxes with a well-established number of photons. At the same time the development of new types of instruments operating with single photons will require advances in new quantum-based calibration methods. The trend towards solid-state lighting requires the development of new calibration methodologies adapted to the properties of these light sources.</p> </td></tr></table> </div> </div> </td> <td width="10"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10"></td> <td width="200" valign="top"> <table width="180" border="0" cellspacing="0" cellpadding="4" bgcolor="#829EBA"> <tr> <td width="100%" height="100%" valign="top"> <table width="100%" border="0" cellspacing="0" cellpadding="0" bgcolor="#FFFFFF"> <tr> <td width="180" height="100%" valign="top"> <table width="180" border="0" cellpadding="3" bgcolor="#FFFFFF" cellspacing="0" height="100%"> <tr align="left" valign="middle" bgcolor="#00498F"> <td height="25" valign="top" bgcolor="#829EBA" class="cadreTrt"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/flc_dir.gif" width="18" height="18" alt=""> Photometry and Radiometry </td> </tr> <tr> <td height="100%" valign="top" class="txt11ptl" align="left"> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/">Overview</a><br> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="units.html">Photometric units</a><br> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccpr/">Committee structure</a><br> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="/web/20200531035549/https://www.bipm.org/utils/en/pdf/CCPR-strategy-document.pdf">Strategic plan</a><br> </td> </tr> </table> </td> </tr> </table> </td> </tr> </table> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="100%" height="5" alt=""> <table width="180" border="0" cellspacing="0" cellpadding="4" bgcolor="#829EBA"> <tr> <td width="100%" height="100%" valign="top"> <table width="100%" border="0" cellspacing="0" cellpadding="0" bgcolor="#FFFFFF"> <tr> <td width="180" height="100%" valign="top"> <table width="180" border="0" cellpadding="3" bgcolor="#FFFFFF" cellspacing="0" height="100%"> <tr align="left" valign="middle" bgcolor="#00498F"> <td height="25" valign="top" bgcolor="#829EBA" class="cadreTrt"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/flc_dir.gif" width="18" height="18" alt=""> International equivalence </td> </tr> <tr> <td height="100%" valign="top" class="txt11ptl" align="left" bgcolor="#F2F5F8"> <a class="introGras" href="https://web.archive.org/web/20200531035549/http://www.bipm.org/kcdb"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/logos/KCDB2.0.png" width="160" border="0"></a><br> </td> </tr> </table> </td> </tr> </table> </td> </tr> </table> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="100%" height="5" alt=""> <table width="180" border="0" cellspacing="0" cellpadding="4" bgcolor="#829EBA"> <tr> <td width="100%" height="100%" valign="top"> <table width="100%" border="0" cellspacing="0" cellpadding="0" bgcolor="#FFFFFF"> <tr> <td width="180" height="100%" valign="top"> <table width="180" border="0" cellpadding="3" bgcolor="#FFFFFF" cellspacing="0" height="100%"> <tr align="left" valign="middle" bgcolor="#00498F"> <td height="25" valign="top" bgcolor="#829EBA" class="cadreTrt"> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/flc_dir.gif" width="18" height="18"> At the BIPM</td> </tr> <tr> <td height="100%" valign="top" align="left"> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/liaisons.html">BIPM liaison and coordination work</a><br> <img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/bullet1.gif" width="16" height="9" alt=""><a class="introGras" href="/web/20200531035549/https://www.bipm.org/en/bipm/people/jviallon.html">BIPM contact person</a><br> </td> </tr> </table> </td> </tr> </table> </td> </tr> </table> </td> <td width="10"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10"></td> </tr>  <tr> <td colspan="3" height="5"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="10" height="5"></td> </tr> </table></center>   <table width="100%" bgcolor="#D3B657"> <tr> <td width="15%"></td> <td width="1000"> <table width="1000" border="0" cellspacing="0" cellpadding="0"> <tr> <td nowrap width="100%"> <style media="all" type="text/css"></style> <div class="menu3"> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/worldwide-metrology/" target="_self">Metrology area:</a></li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/auv/" target="_self">AUV</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/auv/" target="_self">Metrology in the field of Acoustics, Ultrasound and Vibration</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccauv/" target="_self">Committee structure (CCAUV)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/auv/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/" target="_self">Units (SI Brochure)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/gpanfilo.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/electricity-magnetism/" target="_self">EM</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/electricity-magnetism/" target="_self">Metrology in the field of Electricity and Magnetism</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccem/" target="_self">Committee structure (CCEM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/electricity-magnetism/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/electricity-magnetism/units.html" target="_self">Units for electrical quantities</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/electricity/" target="_self">BIPM laboratory work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/comparisons/#PM" target="_self">Ongoing BIPM comparisons</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/calibrations/#electricity" target="_self">BIPM calibrations of electrical standards</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/electricity-magnetism/publications.html" target="_self">BIPM publications in the scientific literature</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/mstock.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/length/" target="_self">L</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/length/" target="_self">Length Metrology</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccl/" target="_self">Committee structure (CCL)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/length/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/length/units.html" target="_self">Unit of length (metre)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/mises-en-pratique/standard-frequencies.html" target="_self">Recommended values of standard frequencies</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/gpanfilo.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/mass/" target="_self">M</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/mass/" target="_self">Mass Metrology</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccm/" target="_self">Committee structure (CCM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/mass/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/mass/units.html" target="_self">Unit of mass (kilogram)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/mass/" target="_self">BIPM laboratory work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/mass/calibrations_mass/" target="_self">Calibration services</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/mass/publications.html" target="_self">BIPM publications in the scientific literature</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/mass/contact.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="current" href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/" target="_self">PR</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/" target="_self">Metrology in the field of Photometry and Radiometry</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccpr/" target="_self">Committee structure (CCPR)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/utils/en/pdf/CCPR-strategy-document.pdf" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/units.html" target="_self">Photometric units</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/photometry-radiometry/liaisons.html" target="_self">BIPM liaison and coordination work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/jviallon.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/" target="_self">QM</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/" target="_self">Metrology in the field of Chemistry and Biology</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccqm/" target="_self">Committee structure (CCQM)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/units.html" target="_self">Unit for amount of substance (mole)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/chemistry/" target="_self">BIPM laboratory work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/comparisons/#QM" target="_self">Comparisons piloted by the BIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/calibrations/#chemistry" target="_self">BIPM calibrations: National ozone standards</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/publications.html" target="_self">BIPM publications in the scientific literature</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/chemistry-biology/liaisons.html" target="_self">BIPM liaison and coordination work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/rwielgosz.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/" target="_self">RI</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/" target="_self">Metrology in the field of Ionizing Radiation</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccri/" target="_self">Committee structure (CCRI)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/units.html" target="_self">SI units</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/ionizing/radionuclides/sir/" target="_self">International Reference System (SIR)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/ionizing/" target="_self">BIPM laboratory work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/comparisons/#RI" target="_self">Ongoing BIPM comparisons</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/calibrations/#ionizing-radiation" target="_self">BIPM calibrations: Ionization chambers</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/publications.html" target="_self">BIPM publications in the scientific literature</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/scientific-output/monographies-ri.html" target="_self"><i>Monographies</i> BIPM</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/ionizing-radiation/liaisons.html" target="_self">BIPM liaison and coordination work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/steven.judge.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/thermometry/" target="_self">T</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/thermometry/" target="_self">Metrology in Thermometry</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/cct/" target="_self">Committee structure (CCT)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/thermometry/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/thermometry/units.html" target="_self">SI base unit (kelvin)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/susanne.picard.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/" target="_self">TF</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/" target="_self">Time and Frequency Metrology</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/cctf/" target="_self">Committee structure (CCTF)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/#strategy" target="_self">Strategic plan</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/timescales/time-server.html" target="_self">What time is it?</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/timescales/" target="_self">Timescales</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/units.html" target="_self">Unit of time (second)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/mises-en-pratique/standard-frequencies.html" target="_self">Recommended values of standard frequencies</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/tai/" target="_self">BIPM technical work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/jsp/en/TimeCalibrations.jsp" target="_self">BIPM calibrations for time transfer</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/publications.html" target="_self">BIPM technical publications</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/tai/annual-report.html" target="_self">BIPM Annual Report on Time Activities</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm-services/timescales/time-ftp.html" target="_self">FTP server of the BIPM Time Department</a></li> <li><a href="https://web.archive.org/web/20200531035549/http://webtai.bipm.org/database/html/" target="_self">Time Department Database</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/time-frequency/liaisons.html" target="_self">BIPM liaison and coordination work</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/patrizia.tavella.html" target="_self">BIPM contact</a></li> </ul> </li> <li><a id="" href="/web/20200531035549/https://www.bipm.org/en/measurement-units/" target="_self">U</a> <ul> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/" target="_self">Measurement units: the International System (SI)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/publications/si-brochure/" target="_self">SI Brochure</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/#si-base-units" target="_self">SI base units</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/measurement-units/#prefixes" target="_self">SI prefixes</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/committees/cc/ccu/" target="_self">Consultative Committee for Units (CCU)</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/metrology/units/liaisons.html" target="_self">BIPM liaison and coordination work</a></li> <li><a href="https://web.archive.org/web/20200531035549/http://physics.nist.gov/cuu/Constants/index.html" target="new">CODATA recommended values of the Fundamental Physical Constants</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/extra/codata-tgfc/" target="_self">CODATA Task Group on Fundamental Constants</a></li> <li><a href="/web/20200531035549/https://www.bipm.org/en/bipm/people/estefania.de.mirandes.html" target="_self">BIPM contact</a></li> </ul> </li> </ul> </div> </td> </tr> </table> </td> <td width="15%"></td> </tr> </table>   <table width="100%" bgcolor="#193B7F" alt="mid blue"><tr><td> <center> <table width="1000" bgcolor="#193B7F" border="0" cellspacing="0" cellpadding="0"> <tr height="60"> <td width="20"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="20" height="60" alt=""></td> <td width="470"><div align="left"><a href="/web/20200531035549/https://www.bipm.org/en/conference-centre/directions/" class="navigationBlanc">BIPM - Pavillon de Breteuil F-92312 Sèvres Cedex FRANCE</a></div></td> <td width="100" class="navigationBlanc"><center><a href="/web/20200531035549/https://www.bipm.org/en/about-us/disclaimer.html" class="navigationBlanc">Disclaimer</a><br><a href="/web/20200531035549/https://www.bipm.org/en/about-us/privacy-policy.html" class="navigationBlanc">Privacy Policy</a></center></td> <td width="410"><div align="right"><a href="/web/20200531035549/https://www.bipm.org/en/about-us/disclaimer.html" class="navigationBlanc">Copyright © BIPM all rights reserved</a></div></td> <td width="20"><img src="/web/20200531035549im_/https://www.bipm.org/utils/common/img/pix.gif" width="20" height="60" alt=""></td> </tr> </table> </center> </td></tr></table>  </body> </html>