Editing Infrared (section)

=== Visible limit ===

Infrared radiation is generally considered to begin with wavelengths longer than visible by the human eye. There is no hard wavelength limit to what is visible, as the eye's sensitivity decreases rapidly but smoothly, for wavelengths exceeding about 700&nbsp;nm. Therefore wavelengths just longer than that can be seen if they are sufficiently bright, though they may still be classified as infrared according to usual definitions. Light from a near-IR laser may thus appear dim red and can present a hazard since it may actually carry a large amount of energy. Even IR at wavelengths up to 1,050&nbsp;nm from pulsed lasers can be seen by humans under certain conditions.<ref name="Sliney1976">{{Cite journal |last=Sliney |first=David H. |last2=Wangemann |first2=Robert T. |last3=Franks |first3=James K. |last4=Wolbarsht |first4=Myron L. |year=1976 |title=Visual sensitivity of the eye to infrared laser radiation |journal=[[Journal of the Optical Society of America]] | volume=66 |issue=4 |pages=339–341 |bibcode=1976JOSA...66..339S |doi=10.1364/JOSA.66.000339 |pmid=1262982 |quote=The foveal sensitivity to several near-infrared laser wavelengths was measured. It was found that the eye could respond to radiation at wavelengths at least as far as 1064 nm. A continuous 1064 nm laser source appeared red, but a 1060 nm pulsed laser source appeared green, which suggests the presence of second harmonic generation in the retina.}}</ref><ref name="LynchLivingston2001">{{Cite book |last=Lynch |first=David K. |url=https://books.google.com/books?id=4Abp5FdhskAC&pg=PA231 |title=Color and Light in Nature |last2=Livingston |first2=William Charles |publisher=Cambridge University Press |year=2001 |isbn=978-0-521-77504-5 |edition=2nd |location=Cambridge, UK |page=231 |quote=Limits of the eye's overall range of sensitivity extends from about 310 to 1,050 nanometers |access-date=12 October 2013 |archive-url=https://web.archive.org/web/20240529134755/https://books.google.com/books?id=4Abp5FdhskAC&pg=PA231#v=onepage&q&f=false |archive-date=29 May 2024 |url-status=live}}</ref><ref name="Saidman1933">{{Cite journal |last=Saidman |first=Jean |date=15 May 1933 |title=Sur la visibilité de l'ultraviolet jusqu'à la longueur d'onde 3130 |trans-title=The visibility of the ultraviolet to the wave length of 3130 |url=http://visualiseur.bnf.fr/ark:/12148/bpt6k3148d |url-status=live |journal=[[Comptes rendus de l'Académie des sciences]] | language=fr |volume=196 |pages=1537–9 |archive-url=https://web.archive.org/web/20131024092515/http://visualiseur.bnf.fr/ark:/12148/bpt6k3148d |archive-date=24 October 2013 |access-date=3 July 2014}}</ref>