photoshop曝光工具如何修改颜色
我想知道 Photoshop 曝光工具是如何工作的（在 CS4 中是图像 -> 调整 -> 曝光...）
共有三个滑块：曝光、偏移和伽玛校正。我只对曝光滑块感兴趣，忽略了其他两个。它似乎试图模拟相机曝光值的行为： http://en.wikipedia.org /wiki/Exposure_value
是否取值 x > 1 和滑块中的 EV，并将所有颜色通道乘以 x^EV？我正在制作一个调整曝光的程序，这种方法似乎足够接近。但难道就没有别的事了吗？
感谢您的回答。
I would like to know how the Photoshop Exposure tool works (In CS4 it's Image -> Adjustments -> Exposure...)
There are three sliders: Exposure, Offset and Gamma Correction. I am interested only in the Exposure slider, ignoring the other two. It seems like it tries to simulate the behavior of exposure value of a camera: http://en.wikipedia.org/wiki/Exposure_value
Does it take a value x > 1 and the EV from the slider, and multiplies all color channels by x^EV? I am making a program that adjusts exposure and this approach seems close enough. But isn't there something else?
Thanks for your answers.
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曝光滑块将通过改变相对于 RGB = 0,0,0 的图像亮度（亮度通道）
- 最暗点
- 最亮点
- 以及之间的所有点
如果图像中最暗的点是黑色（RGB = 0,0,0），那么它不会改变，但其他所有点都会改变。
纬度（最暗和最亮之间的范围）也会发生变化，当您变亮时纬度会增加，当您变暗时纬度会减少。
查看此情况的最佳方法是创建一个简单的 jpeg，其中包含黑色条带、白色条带、深灰色条带和浅灰色条带。确保没有颜色信息（Command-shift-u）。使直方图窗格可见，添加曝光调整图层，移动滑块并观察直方图值的变化。
Exposure slider will change the brightness (luma channel) of the image relative to RGB = 0,0,0 by altering
- the darkest point
- brightest point
- and all the points in between
If the darkest point in the image is black (RGB = 0,0,0) then that will nto change but every other point will.
The latitude (range between darkest and lightest) will also change, increasing latitude as you brighten, decreasing latitude as you darken.
The best way to see this is to create a simple jpeg with a black band a white band, a dark grey band and a light grey band. Make sure there is no color information (Command-shift-u). Make the Histograms pane visible, add an exposure adjustment layer, move the slider and watch the histo values change.