What is the best way to transform a colored picture to black and white in Adobe Photoshop?

Just follow this step

Image -> Adjustment ->Black & White

or shortcut  ALT+SHIFT+CTRL+B

Agree with experts

*************************

press image button, then adjustment, them black and white

  Ctrl+Shift+U  ( OR )  Alt + Shift + Ctrl + B

ctrl+u and use your colour

For me just use camera raw filter for best adjustments  and tones of black and white..

"Desaturate" is the best way. Shortcut is "Ctrl+Shift+U.

Also play with the saturation if you need to reduce the color quantity through "Hue / Saturation" from Adjustment menu.

Alt+Ctrl+Shift+B and hit OK

• hue & saturation 
• gradient map
• vibrance 
• Black & white Adjustment.
• You can also add a black layer above the layer you want to make black an white, and change the blending option to color

As in photoshop CS6 command, colored photo transformation into black and white, all you need to do click the Image menu and choose the Adjustment and browse down and pick the Black and white then click OK; displayed image automatically will change the color.

simple from keyboard press alt+ctrl+shift + B