Black and White

[Marpel]

Disregarding for a second, any subsequent tonal manipulations for effect, is there a best method to initially convert a colour image into a black and white image.

I tried a straight Colour desaturation, then compared that result to a Convert > 16 bit black and white on the same colour image and, although visually similar, there is a difference when using Comp > Absolute Difference. Does this mean one method loses quality/detail more than the other, or is there a better method than these two?

Marv

[jsachs]

The most straightforward method is to extract the Luminance channel which is a weighted average of the red, green and blue channels based on the eye's relative sensitivity to each color. I believe this is the method used in the Convert transformation. The default color of the Monochrome transformation when using the Filter method should also correspond very closely to the Luminance channel.

[couman]

I often scan through the R,G,B, luminance, and brightness channels to see what I prefer for a particular image. If 2 or more have appealing features, I use stack images to combine them.

[Marpel]

O.K., thanks very much Jonathan and Bob for the suggestions.

Marv