Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!


Click here to return to the 'Easily convert photos to black and white in iPhoto 6' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
Easily convert photos to black and white in iPhoto 6
Authored by: lukeandrews on Mar 26, '07 08:44:28AM

I'm pretty sure the Black & White button just does the same thing as turning the saturation down completely.

While this certainly does give you a black and white image, it doesn't reflect how we really perceive light, nor does it reflect how black and white film works. The reason is that the RGB colour model isn't balanced for luminance -- our eyes perceive green as being very light, red as less light, and blue as quite dark.

When you de-saturate an image of its colour evenly across all three colour channels, the result is that anything green will appear darker than it did in the coloured version.

A "good" black and white conversion will compensate for that by adjusting the relative brightness of the red, blue and green channels.



[ Reply to This | # ]
Easily convert photos to black and white in iPhoto 6
Authored by: lukeandrews on Mar 26, '07 08:47:25AM

One last thought: if you have Photoshop, you can easily check the difference between de-saturation and a B&W conversion by comparing a photo that has been de-saturated but is still in RGB to one switched to Grayscale mode. When Photoshop does the latter, it compensates for the relative luminance of the colour channels.



[ Reply to This | # ]