As Michael Freeman writes in 'The Complete Guide to Black & White Digital Photography
', 2009 (p140), " ... 'full' black & white photography means anticipating, selecting and composing monochrome right from the start. And the only way to do this is to train oneself to think and see in black and white. There are optical aids ..., but these are really tricks to fool the eye for a short while into ignoring the colour in a scene. More effective long term is constant practice and experience in mentally filtering out the colour information."