NOT done by desaturation
A B&W conversion technique that you may want to avoid
- Because it has no redeeming features other than simplicity
- Some editing software offer it as a menu option under COLOR thus tempting users to use it.
- The resulting B&W conversions are rarely (like never) better than the alternatives
- This is best illustrated by yesterday’s overview example
Why would you ever use a B&W conversion that potentially could do this?
Especially when there are better alternatives??
How each desaturation is computed…
Are you surprised that a straight desaturation of the color image, as a means of B&W conversion, produced a uniform gray image? Once you know how desaturation is accomplished the mystery will be solved.
Desaturation B&W conversion is done by averaging the image’s RGB component values, pixel by pixel. The above image is pure RGB. This means that its color’s component R/G/B values from left to right are –
- Red = 255/0/0
- Green = 0/255/0
- Blue = 0/0/255
To determine each color’s gray conversion value, compute the average of each component’s strength –
- Red = (255+0+0)/3 = 85
- Green = (0+255+0)/3 = 85
- Blue = (0+0+255)/3 = 85
And, WOW, look at that! They’re all the same.They all convert to the same shade of gray. Maybe, just maybe – desaturation isn’t that great of a technique for B&W conversion (although at times you can get away with it; it depends on the image’s colors).
Now we know why the desaturation option gave the result that it did in our R/G/B image test panel.
Tomorrow – Grayscale