Digital BW, The Print

Louis Dina wrote:
> 
> 
> Lincoln,
> 
> Channel Mixer simply defaults to 100% of the red channel upon opening,
> but that doesn't mean it is the default B&W conversion formula for
> Photoshop. When you click 'grayscale' in Channel Mixer, it just jumps
> to the first available channel, which is red, and leaves it at 100% so
> you can start fiddling around with the sliders. That gives you a
> display of the Red channel only, with both Green and Blue channels set
> to 0%. It's just a blank canvas and a starting point.
> 
> Looking at any grayscale conversion using Mode>Grayscale, you can see
> that the result is not the Red channel only. All the information I
> can find suggests 30%R, 60%G, 10%B is about right for a standard mode
> change. If it isn't that, it is close.

According to _mastering black and white digital photography_ (
http://www.amazon.com/Mastering-Black-White-Digital-Photography/dp/1579907075 ),
Photoshop uses 30% red, 59% green and 11% blue, which jives with
the 30/60/10 number.  Desaturate gives equal weight to all the channels.

Dana