Mired

<h2 id="examples">Examples</h2>
<p>A blue sky, which has a color temperature <i>T</i> of about 25000 K, has a mired value of <i>M</i> = 40 mireds, while a standard electronic <a href="/facts/Photography/ezLPT43M">photography</a> <a href="/facts/Flash_(photography)/bfegk3Xy">flash</a>, having a color temperature <i>T</i> of 5000 K, has a mired value of <i>M</i> = 200 mireds.
</p>
Common color temperature and mired equivalents<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>: 40 <table><tbody><tr><th>Light source</th><th><a href="/facts/Color_temperature/g77MjsPM">Temp. (K)</a></th><th>Mired</th></tr><tr><td>Skylight (clear, blue)</td><td>15000–27000</td><td>40–70</td></tr><tr><td>Shade, illuminated by skylight</td><td>10000–12000</td><td>80–100</td></tr><tr><td>Skylight (hazy)</td><td>7500–8400</td><td>120–130</td></tr><tr><td>Overcast</td><td>6700–7000</td><td>140–150</td></tr><tr><td>Electronic flash</td><td>6200–6800</td><td>150–160</td></tr><tr><td>Sunlight (hazy)</td><td>5800</td><td>170</td></tr><tr><td>Daylight (average)</td><td>5500–6000</td><td>170–180</td></tr><tr><td>Daylight (morning / afternoon)</td><td>5000–5500</td><td>180–200</td></tr><tr><td>LED (cool white)<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a></td><td>3100–4500</td><td>220–320</td></tr><tr><td>Professional tungsten</td><td>3200</td><td>310</td></tr><tr><td>Incandescent bulb (100 W)</td><td>2900</td><td>340</td></tr><tr><td>Incandescent bulb (40 W)</td><td>2650</td><td>380</td></tr></tbody></table>
<h2 id="applications">Applications</h2>
<h3>Photographic filter and gel</h3>

<p>In <a href="/facts/Photography/ezLPT43M">photography</a>, mireds are used to indicate the color temperature shift provided by a <a href="/facts/Photographic_filter/H1EXnTbX">filter</a> or <a href="/facts/Color_gel/ggECgb7q">gel</a> for a given <a href="/facts/Film/wM3b9Kk3">film</a> and light source. For instance, to use daylight film (5700 K) to take a photograph under a tungsten light source (3200 K) without introducing a <a href="/facts/Color_cast/k3w12Pba">color cast</a>, one would need a corrective filter or gel providing a mired shift
</p>

10
              
                6
              
            
            5700
          
        
        −
        
          
            
              10
              
                6
              
            
            3200
          
        
        ≈
        −
        137
         
        
          
            MK
          
          
            −
            1
          
        
        .
      
    
    {\displaystyle {\frac {10^{6}}{5700}}-{\frac {10^{6}}{3200}}\approx -137~{\text{MK}}^{-1}.}

<p>This corresponds to a color temperature blue (CTB) filter.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> Color gels with negative mired values appear green or blue, while those with positive values appear amber or red.
</p>
<h3>CCT calculation</h3>
<p>A number of mathematical methods, including Robertson's, calculate the <a href="/facts/Correlated_color_temperature/g77MjsPM">correlated color temperature</a> of a light source from its chromaticity values. These methods exploit the relatively even spacing of the mired uint internally.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
</p>
<h3>Color description</h3>
<p>Apple's <a href="/facts/HomeKit/YGcIMtuM">HomeKit</a> uses the mired unit for specifying color temperature.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
</p>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>How Many? A Dictionary of Units of Measurement (PDF). Pasig City. 20 March 2013. p. 239.{{cite book}}:  CS1 maint: location missing publisher (link) <a href="http://alltootechnical.weebly.com/uploads/4/0/7/5/4075543/dict_units.pdf" target="_blank">http://alltootechnical.weebly.com/uploads/4/0/7/5/4075543/dict_units.pdf</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Ohta, Noboru; Robertson, Alan R. (2005). Colorimetry: Fundamentals and Applications. Wiley. p. 84. ISBN 0-470-09472-9. <a href="0-470-09472-9" target="_blank">0-470-09472-9</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Priest, Irwin G. (February 1932). "A proposed scale for use in specifying the chromaticity of incandescent illuminants and various phases of daylight" (abstract). JOSA. 23 (2): 41–45. doi:10.1364/JOSA.23.000041. <a href="http://www.opticsinfobase.org/abstract.cfm?URI=josa-23-2-41" target="_blank">http://www.opticsinfobase.org/abstract.cfm?URI=josa-23-2-41</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Smith, Robb (1975). The Tiffen practical filter manual. American Photographic Book Publishing Co., Inc. ISBN 0-8174-0180-6. LCCN 75-21574. <a href="0-8174-0180-6" target="_blank">0-8174-0180-6</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"Understanding color temperature". Westinghouse. Retrieved 18 August 2024. <a href="https://www.westinghouselighting.com/color-temperature.aspx" target="_blank">https://www.westinghouselighting.com/color-temperature.aspx</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Brown, Blain (2002). Cinematography: Theory and Practice : Imagemaking for Cinematographers. Focal Press. p. 172. ISBN 0-240-80500-3. <a href="0-240-80500-3" target="_blank">0-240-80500-3</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>"Mired Shift Gel Table" (PDF). <a href="https://www.danberens.co.uk/uploads/3/0/0/6/30067935/mired_shift_gel_and_camera_filter_tables.pdf" target="_blank">https://www.danberens.co.uk/uploads/3/0/0/6/30067935/mired_shift_gel_and_camera_filter_tables.pdf</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Robertson, Alan R. (November 1968). "Computation of Correlated Color Temperature and Distribution Temperature". JOSA. 58 (11): 1528–1535. Bibcode:1968JOSA...58.1528R. doi:10.1364/JOSA.58.001528. <a href="/wiki/JOSA" target="_blank">/wiki/JOSA</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>"HMCharacteristicTypeColorTemperature". Apple Developer Documentation. <a href="https://developer.apple.com/documentation/homekit/hmcharacteristictypecolortemperature" target="_blank">https://developer.apple.com/documentation/homekit/hmcharacteristictypecolortemperature</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
</ol>

Mired open-in-new

Mired