Colour Black and white

Exercise Black and white .
Digital : I took an average exposure of this set up of still life, lit by window light. .
Tomato, lemon, and green peas against a blue backing.

From aperture 3. In my mac.  I use  black and whiter converter mode. Then used the red green and blue filters. Interesting to see which way they swing to give the effect of close shade to colour.

neutral 

By reducing the red filter, sliding to the left, darkens red Slightly, bringing the tone to what would represent a tomato.

Same with green, but adjustment is slight. As green renders a similar tone to blue, and blue here would have taken a darker tone.

Here, sliding the blue filter. Most certainly changes things . Is this why blue is used for blue screening?

Using the colour sliders :

Here I mad changes with red, Yellow, green and Blue . The other sliders not used were light  .Violet and light blue. 

Stating with RED

Here using the yellow. I found I had to slide to the right to brighten . 

Blue very slight adjustment