The camera sensor captures the image in a linear fashion which results in a very dark picture. We can mimic this by applying curves to a sample picture. The picture has been converted to 16 bit to avoid any image 'banding' that may happen if we process this as 8 bit.
Here is the image as it came from the camera. Note that the histogram has a good spread of tones.
|The picture straight from the camera.|
Now compare the image above to the one below that has been adjusted to resemble the linear capture from the sensor. This has been done by applying curves.
|How the sensor captures the picture.|
Finally we bring the image back to it's original state by applying another curve, the opposite to the curve applied to the picture above.
|The dark image (top) with curves applied to bring the tones back to the original (bottom).|
* Note that all the images on this page have been converted to 8 bit to enable them to be used in this exercise!