Change Color Depth

Use this command to convert a picture between 48-bit color (3 × 16 bits) and classical 24-bit color (3 × 8 bits). You can also use it to convert pictures to 8-bit or 16-bit color.

A 48-bit color depth can express vastly more colors than 24 bits: 224 = 16,777,216 different colors, while 248 = 281,474,976,710,656 colors. Although this difference is not visible to the human eye (the human eye can distinguish "only" about 10 million colors), it does manifest when a picture undergoes digital processing, because many more details are available.

For example, during major brightening of a strongly underexposed photograph, formerly "almost black" areas may flow into a single color. This is caused by the fact that only a narrow portion of the histogram was used in the original picture. If, however, the source picture is stored at a 48-bit color depth, then there is a much higher chance that even this reduced portion of the histogram will be wide enough for the pixels in this area to have differing values, so that finer color transitions remain after brightening.

The disadvantages of 48-bit color depth are larger file sizes, the limited number of programs that support this color depth, and a restricted choice of formats. (Within Zoner Photo Studio, you can only save with 48-bit color depth do the TIFF, PNG, and HDP formats—the JPEG format does not support 48-bit color depth.)