gamma 色彩饱和度
Explained in very simple terms, "gamma" is a measurement that describes a digital device’s representation of light intensity. Digital devices do not deliver or record light intensity in a linear fashion, but on a curve: gamma expresses the degree of that curve, or its deviation from a straight line. This is not a limitation of technology, but of evolution: the human eye does not respond linearly to brightness either, and our digital devices are trying to compensate for that fact.
用非常简单的术语解释，“伽马”是一种描述数字设备光强度表示的度量。 数字设备不是以线性方式传递或记录光强，而是在曲线上传递：伽玛表示该曲线的程度或其与直线的偏差。 这不是技术的限制，而是技术的发展：人眼也不会对亮度做出线性响应，我们的数字设备正在努力弥补这一事实。
Gamma does not affect pure white or black, but mid-tones: a higher gamma value will make images appear darker overall, and a lower one, lighter.
灰度系数不会影响纯白色或黑色，但会影响中间色调：较高的灰度系数值会使图像整体看起来更暗，而较低的灰度系数会更亮。
For years this was a major issue between Macs and PCs when it came to visual representation: Apple had the default gamma set to 1.8, while Microsoft insisted on a default value of 2.2 in Windows. As a result, a fine print photograph that looked fine on a Mac would tend to appear dark on a PC, and an image transferred from PC to Mac would often look washed-out and over-bright. Historically, each value has had its adherents and detractors: 2.2 gamma has higher contrast and more support (digital television transmissions in North America have a gamma of 2.2, as does the sRGB color space), but 1.8 was useful for the first generations of desktop publishing, and many feel that it has more subtle shades and tones. (And they are not the only options: digital cinema uses a gamma of 2.6).
This issue has now finally been resolved: Apple capitulated, and from Snow Leopard (OS X 10.6) on, the Apple operating system has the same gamma as Windows. Images created on older versions of OS X brought forward into Snow Leopard may appear slightly darker as a result. This change also means that images will tend to remain steadfast in color, and not appear lighter or darker as they move across platforms.
现在，这个问题终于得到解决：Apple屈服了，从Snow Leopard(OS X 10.6)开始，Apple操作系统的伽玛与Windows相同。 结果，在雪豹中使用旧版OS X创建的图像可能会显得有些暗。 这种变化还意味着图像将趋于保持稳定的颜色，并且在跨平台移动时不会显得更亮或更暗。
Of course none of this compensates for the fact that people miscalibrate their own computer monitors all the time, but there’s nothing we can do about that.
当然，这些都不能弥补人们一直在校准自己的计算机显示器这一事实，但是我们对此无能为力。
进一步阅读 (Further Reading)
If you would like to to learn more than you would ever want to know about gamma, Norman Koren’s site is the definitive resource. (So much so that I’ll even forgive his use of Comic Sans).
如果您想了解更多关于伽玛的知识， Norman Koren的网站就是您的权威资源。 (以至于我什至会原谅他对Comic Sans的使用)。
翻译自: /385/Color-for-Web-Designers-Understanding-Gamma
gamma 色彩饱和度
