Part 3 - Ex 4 - Colours into Tones in Black & White

This exercise was all about showing that understanding colour in black and white photography gives a powerful tonal control, allowing emphasis of certain objects while suppressing others.

Because I was using digital images I had only to take one shot of an arrange still life with 4 objects coloured red, blue, yellow and green with a mid grey card or as I chose to do, have a mid grey background. I then converted the colour image in lightroom to black & white, firstly neutral with all B&W Mix colour channels at zero to represent no filters, then with the B&W red channel at +100 to represent a red filter, then similarly adjusting each channel to represent blue, yellow and green filters then note the tonal changes that occurred in the image.

Original Colour Image

As can be seen, I used a grey top as a background, a banana, pepper, lettuce and pieces of lego to represent the relative colours and light the scene with window light and a reflector to fill in some shadows.

No Filter

With no filter all the colours have their own tonal value with only yellow at a similar brightness to the mid tone grey and the others all darker.

Red Filter

With the red filter it has a dramatic effect on the red pepper, brightening it to a similar tone as the the grey background and with the distinctive shape of the banana and knowing they are all generally yellow, the now similarly toned pepper makes the mind presume it is either an orange or yellow pepper where as in the image with no filter it was possible to imagine a red or green pepper from its tone.

Blue Filter

Here with a blue filter we find it is the blue lego pieces that now change in tone, appearing brighter than the mid grey background. Suggesting again they could have been original a bright colour like yellow or orange.

Green Filter

This time it is the lettuce that has been brightened with the application of the green filter. Now a similar tone to the grey background which in turn throws a question mark over the viewers perception of its original colour.

Yellow Filter

The yellow filter has dramatic effect on the banana now a very bright object almost burnt out. It now stands out from all the other objects which remain either mid toned or dark. 

Now understanding that a filter will allow that particular colours' light through and brighten it this has been a very worthwhile exercise, where I found out some of the effects that can be applied to black & white images by altering the colour channels to create different tones for individual objects. It was noted that the mid grey background remained exactly the same throughout the set of images.