Editing Color balance (section)

{{Short description|Adjustment of color intensities in photography}}
{{About|the process applied to still images|the equivalent process applied to video|Color grading}}
[[File:Lily-M7292-As-shot-and-manual.jpg|thumb|right|300px|The left half shows the photo as it came from the digital camera. The right half shows the photo adjusted to make a gray surface neutral in the same light.]]

In [[photography]] and [[image processing]], '''color balance''' is the global adjustment of the intensities of the colors (typically red, green, and blue [[primary colors]]).  An important goal of this adjustment is to render specific colors – particularly neutral colors like white or grey – correctly. Hence, the general method is sometimes called '''gray balance''', '''neutral balance''', or '''white balance'''.  Color balance changes the overall mixture of colors in an image and is used for [[color correction]]. Generalized versions of color balance are used to correct colors other than neutrals or to deliberately change them for effect. ''' White balance''' is one of the most common kinds of balancing, and is when colors are adjusted to make a white object (such as a piece of paper or a wall) appear white and not a shade of any other colour.

Image data acquired by sensors – either [[photographic film|film]] or electronic [[image sensor]]s – must be transformed from the acquired values to new values that are appropriate for color reproduction or display.  Several aspects of the acquisition and display process make such color correction essential – including that the acquisition sensors do not match the sensors in the human eye, that the properties of the display medium must be accounted for, and that the ambient viewing conditions of the acquisition differ from the display viewing conditions.

The color balance operations in popular [[image editing]] applications usually operate directly on the red, green, and blue channel [[pixel]] values,<ref>{{Cite book| title = The Gimp for Linux and Unix | author = Phyllis Davis | publisher = Peachpit Press | year = 2000 | isbn = 978-0-201-70253-8 | url = https://books.google.com/books?id=0sEnoWrMw-gC&q=%22color+balance%22+channels&pg=PA135 | page = 134}}</ref><ref>{{Cite book| title = Adobe Photoshop 6.0 | author = Adobe Creative Team | publisher = Adobe Press | year = 2000 | isbn = 978-0-201-71016-8 | url = https://books.google.com/books?id=MRtx2-0GZc4C&q=%22color+balance%22+channels&pg=PA277 | page = 278 }}{{Request quotation|date=April 2021}}<!-- Did Adobe explicitly spell out their algorithm for white balance, which most likely 
uses CIEXYZ or similar to select an illuminant behind the scenes, or did the book just explain how to balance with the channel mixer?  One of these things sports this statement and the other doesn't. -->  </ref> without respect to any color sensing or reproduction model.  In film photography, color balance is typically achieved by using [[color correction filter]]s over the lights or on the camera lens.<ref>{{Cite book| title = Cinematography: Theory and Practice : Imagemaking for Cinematographers, Directors, and Videographers | author = Blain Brown | publisher = Focal Press | year = 2002 | isbn = 978-0-240-80500-9| url = https://books.google.com/books?id=1JL2jFbNPNAC&q=%22color+balance%22&pg=PA170 | page=170 }}</ref>