4 different methods to convert colour images to B&W,
with user option of histogram stretch.

Option 1 - Converts image's average RGB to Channel Mixer values.
Option 2 - Channel Mixer method with default luminance settings.
Option 3 - Standard desaturation method (non-adjustable).
Option 4 - Greyscale method, with 16 million color depth.
Option 5 - Creates 4 image contact sheet to compare methods.

Indiviual conversion methods may look similar in tonal range,
but can display significant differences with certain colours.

Use the contact sheet to decide which method best suits your image,
particularly where there is a dominant colour.