What an unprocessed photo looks like:

"Sensor data with the 14 bit ADC values mapped to 0-255 RGB.It's not even black-and-white, it's gray-and-gray. This is becuase while the ADC's output can theoretically go from 0 to 16382, the actual data doesn't cover that whole range: Histogram of raw imageThe real range of ADC values is ~2110 to ~136000. Let's set those values as the white and black in the image: Vnew = (Vold - Black)/(White - Black)ProgressMuch better, but it's still more monochromatic then I remember the tree being."

"Camera sensors aren't actually able to see color: They only measure how much light hit each pixel. In a color camera, the sensor is covered by a grid of alternating color filters: Let's color each pixel the same as the filter it's looking through: Bayer matrix overlayThis version is more colorful, but each pixel only has one third of it's RGB color. To fix this, I just averaged the values each pixel with it's neighbors:"

"However, the image is still very dark. This is because monitors don't have as much dynamic range as the human eye, or a camera sensor: Even if you are using an OLED, the screen still has some ambient light reflecting off of it and limiting how black it can get. There's also another, sneaker factor causing this: True linear gradientOur perception of brightness is non-linear."

Raw sensor outputs are often mapped to 0–255 for display, but the ADC's theoretical range is rarely fully used, so black and white levels must be remapped using Vnew = (Vold - Black)/(White - Black). Camera sensors measure light intensity, not color, and use a Bayer filter mosaic so each pixel records only one channel; neighboring pixels must be combined via demosaicing to reconstruct color. Displays have far less dynamic range than sensors and ambient reflections limit deep blacks. Human brightness perception is non-linear, and color spaces like sRGB allocate more code values to darker tones, so linear sensor data looks too dark unless a non-linear curve or tone mapping is applied.

Read at Maurycyz