Editing Colors of noise (section)

==Informal definitions==
There are also many colors used without precise definitions (or as synonyms for formally defined colors), sometimes with multiple definitions.

===Red noise===
* A synonym for Brownian noise, as above.<ref>{{Cite web|url=https://www.ears.dmu.ac.uk/rubrique.php3?id_rubrique=93|archive-url=https://web.archive.org/web/20060522073646/https://www.ears.dmu.ac.uk/rubrique.php3?id_rubrique=93|url-status=dead|title=Index: Noise (Disciplines of Study [DoS&#93;)<!-- Bot generated title -->|archive-date=22 May 2006}}</ref><ref>{{cite journal |last1=Gilman |first1=D. L. |last2=Fuglister |first2=F. J. |last3=Mitchell Jr. |first3=J. M. |title=On the power spectrum of "red noise" |journal=Journal of the Atmospheric Sciences |volume=20 |number=2|pages=182–84 |doi=10.1175/1520-0469(1963)020<0182:OTPSON>2.0.CO;2 |bibcode=1963JAtS...20..182G |year=1963 |doi-access=free }}</ref> That is, it is similar to pink noise, but with different spectral content and different relationships (i.e. 1/f for [[pink noise]], while 1/f<sup>2</sup> for red noise, or a decrease of 6.02&nbsp;dB per octave).
* In areas where terminology is used loosely, "red noise" may refer to any system where power density decreases with increasing frequency.<ref>{{Cite journal|title=Red noise and regime shifts|author=Daniel L. Rudnick, Russ E. Davis|journal=Deep-Sea Research Part I|volume=50|issue=6|year=2003|pages=691–99|url=https://www-pord.ucsd.edu/~rdavis/publications/Red_Noise.pdf|doi=10.1016/S0967-0637(03)00053-0|bibcode = 2003DSRI...50..691R }}</ref>
<!--
====Orange noise==== The definition at https://www.ptpart.co.uk/colors-of-noise/ is a joke, not a serious definition. -->

===Green noise===
{{Listen|filename=GreenNoise.ogg|title=10 seconds of Wisniewski's version of green noise|description=}}
* The mid-frequency component of white noise, used in [[halftone]] [[dithering]]<ref>{{cite journal
| first1 = Daniel Leo
| last1  = Lau
| first2 = Gonzalo R.
| last2 = Arce
| first3 = Neal C.
| last3 = Gallagher
| title = Green-noise digital halftoning
| journal = Proceedings of the IEEE
| volume  = 86
| number   = 12
| year    = 1998
| pages   = 2424–42
| doi=10.1109/5.735449
}}</ref>
* Bounded Brownian noise
* Vocal spectrum noise used for testing audio circuits<ref name="comp.dsp FAQ">{{cite newsgroup
 | title = Colors of noise pseudo FAQ, version 1.3
 | author = Joseph S. Wisniewski
 | date = 7 October 1996
 | newsgroup = comp.dsp
 | url = https://www.ptpart.co.uk/colors-of-noise/
 | access-date = 2011-03-01
 | url-status = dead
 | archive-url = https://web.archive.org/web/20110430151608/https://www.ptpart.co.uk/colors-of-noise
 | archive-date = 30 April 2011
 }}</ref>
* Joseph S. Wisniewski writes that "green noise" is marketed by producers of ambient sound effects recordings as "the background noise of the world". It simulates the spectra of natural settings, without human-made noises. It is similar to pink noise, but has more energy in the area of 500&nbsp;Hz.<ref name="comp.dsp FAQ"/>

===Black noise===

* [[Silence]]
* [[Infrasound]]<ref>{{Cite web|url=https://vigilantcitizenforums.com/threads/david-bowie-and-the-black-noise.579/|title=David Bowie and the Black Noise|website=The Vigilant Citizen Forums|date=21 May 2017 }}</ref>
* Noise with a 1/''f''{{i sup|''β''}} spectrum, where {{nowrap|''β'' > 2}}. This formula is used to model the frequency of natural disasters.<ref>{{cite book |first=Manfred |last=Schroeder |title=Fractals, Chaos, Power Laws: Minutes from an Infinite Paradise |url=https://books.google.com/books?id=Qpa77Jl2rvQC&pg=PA129 |pages=129–30 |publisher=Courier Dover |year=2009 |isbn=978-0486472041}}</ref>{{clarify|reason=What is the relation between "natural disasters" and "noise"?|date=January 2018}}
* Noise that has a frequency spectrum of predominantly zero power level over all frequencies except for a few narrow bands or spikes. ''Note:'' An example of black noise in a facsimile transmission system is the spectrum that might be obtained when scanning a black area in which there are a few random white spots. Thus, in the time domain, a few random pulses occur while scanning.<ref>{{cite web|url=https://glossary.its.bldrdoc.gov/fs-1037/dir-005/_0649.htm|title=Definition of "black noise" – Federal Standard 1037C|access-date=28 April 2008|archive-url=https://web.archive.org/web/20081212191754/https://glossary.its.bldrdoc.gov/fs-1037/dir-005/_0649.htm|archive-date=12 December 2008|url-status=dead}}</ref>
* Noise with a spectrum corresponding to the [[blackbody]] radiation (thermal noise). For temperatures higher than about {{val|3|e=-7|u=K}} the [[Black-body radiation#Wien's displacement law|peak of the blackbody spectrum]] is above the upper limit of human [[hearing range]]. In those situations, for the purposes of what is heard, black noise is well approximated as [[violet noise]]. At the same time, [[Hawking radiation]] of [[black hole]]s may have a peak in hearing range, so the radiation of a typical [[stellar black hole]] with a mass equal to 6 solar masses will have a maximum at a frequency of 604.5&nbsp;Hz – this noise is similar to green noise. A formula is: <math>f_{\text{max}} \approx 3627 \times {\text{M}_\odot \over \text{M}}</math>&nbsp;Hz.  Several examples of audio files with this spectrum can be found [https://physics.stackexchange.com/a/216688/92058 here].{{citation needed|reason=Looks like original research, or a niche interest.|date=October 2023}}

===Noisy white===

In [[telecommunication]], the term '''noisy white''' has the following meanings:<ref>{{cite web|url=https://www.its.bldrdoc.gov/fs-1037/dir-024/_3570.htm|url-status=dead|archive-url=https://web.archive.org/web/20210608074217/https://www.its.bldrdoc.gov/fs-1037/dir-024/_3570.htm|archive-date=8 June 2021|title=Definition: noisy white|website=its.bldrdoc.gov}}</ref>
* In [[Fax|facsimile]] or display systems, such as [[television]], a nonuniformity in the [[white area]] of the image, ''i.e.'', document or picture, caused by the presence of [[noise]] in the received [[signal]].
* A signal or [[signal level]] that is supposed to represent a white area on the object, but has a noise content sufficient to cause the creation of noticeable black spots on the display surface or [[record medium]].

===Noisy black===

In [[telecommunication]], the term '''noisy black''' has the following meanings:<ref>{{cite web|url=https://www.its.bldrdoc.gov/fs-1037/dir-024/_3569.htm|url-status=dead|archive-url=https://web.archive.org/web/20210608074217/https://www.its.bldrdoc.gov/fs-1037/dir-024/_3569.htm|archive-date=8 June 2021|title=Definition: noisy black|website=its.bldrdoc.gov}}</ref>
* In [[Fax|facsimile]] or display systems, such as [[television]], a nonuniformity in the black area of the image, ''i.e.'', document or picture, caused by the presence of [[noise]] in the received signal.
* A signal or [[signal level]] that is supposed to represent a black area on the object, but has a noise content sufficient to cause the creation of noticeable non-black spots on the display surface or [[record medium]].