A yellow black and white Sofa

I've previously tried to edit a picture by isolating one colour before, with little success. Today in my schools's libary i captured a simple photo of the sofas using a f3.1, medium shutter speed ans ISO of 300.
I then uploaded it into Photoshop where i used the quick mask mode to select anything yellow. After i coloured anything yellow red, i went to adjustments, black and white and pressed ok. This was the end result.

I've seen this technique used before and have been eager to try it for myself, i'm grad i did. and hope to use this method again.