Seeing in Black & White

With all due respect to the great songwriter Paul Simon, everything doesn’t look worse in black and white.

So what do I mean by ‘seeing in black and white’? Well, black and white photography is different from colour photography. Some might say, ‘Well, duh!’ But it is. It requires a different way of seeing and viewing. I’ve heard some people say they just can’t get black and white down. Everything just looks muddled. Why is that? It’s because in the technicolour world we live in colour provides visual interest and contrast. In black & white, or rather shades of grey, there is no direct colour to provide that contrast. In most cases, the contrast has to be created. This requires time to learn and requires a different way of seeing.

Let’s take a look at a sample image to see what I’m getting at. The image below is one I created in Photoshop. It’s a simple, three swatch colour pattern containing three primary colours of red, green and blue. Each has been set to a value of 128 but that value doesn’t really matter.

We can tell that it’s red, green and blue because of the colours.

RGB Colour Block (click for larger version)

But what happens when we convert it to black and white?  Below is a straight conversion to black and white using the Channel Mixer in Photoshop with no adjustments.  The default mix for this is 40% Red, 40% Green and 20% Blue to give a total of 100%.

Channel Mixer Default (click for larger version)

In the immortal words of cartoon dog Scooby Doo…. Ruh roh, Shaggy.  What happened?  Where’d our difference between red and green go?  If we increased the Blue to 40% as well, the entire block would be the same shade of grey.

In the world of grey, many colours in our world translate to the same or very similar shades of grey due to the way they reflect light.  If I’d made the red or green a different number, say 175, then we’d see a slight difference between the two swatches but still not much.  This is what trips a lot of people up and why they get black and white images that lack contrast.  This is where seeing in black and white comes into play.

Let’s look at the same colour block image again but in a different way.  Let’s look at it in terms of each individual colour channel.  Below we have the Red, Green and Blue channels chosen individually in Photoshop.

Red Channel (click for larger version)

Green Channel (click for larger version)

Blue Channel (click for larger version)

Each of these shows the respective colour channel at 100% and the other two channels at 0%.  What’s happened?  What we’ve done, for all intents and purposes is put a red, green and blue filter over the lens and shot the colour block with black and white film.

You’ll see people state in various places on the web that ‘I used a red filter because it darkens blue skies’.  While that may be true, it’s not the entire story.  It doesn’t really show an understanding of what the filter is doing.  So let’s examine that.

Light travels in waves.  Each colour of light has a different wavelength.  I’m not going to go into a technical dissertation of what visible colour wavelengths are.  You’re smart and no doubt know that Google is your friend.  Using a search string like ‘wavelengths of visible light‘ will turn up any number of explanations.  Or you can just click the link 😉  The types of filters that are used on lenses for black and white film are made to block or absorb certain wavelengths and allow others to pass.  A red filter passes red and blocks/absorbs blue and green.  By passing red, anything that is red or contains red tones gets more exposure and other colours get less exposure.  More exposure means lighter tones.  And voila, we’ve created contrast.  The red filter doesn’t actually darken the sky.  What it does is allow the red to be exposed normally and underexposes the blue of the sky giving the impression of darkening the sky and, effectively, increasing or rather creating contrast.  A yellow filter works similarly but with light in the yellow wavelengths.  Now, these wavelenghts aren’t discrete.  There is overlap so the yellow filter will affect reds and oranges a bit too.    Interestingly, it’ll also affect greens.  Why?  Because a lot of what we see as green in the world (e.g., grass, leaves) is actually comprised of a good amount of yellow.  Green filters will have a similar effect on green/greenish colours and a blue filter on blue/blueish colours.

This brings us back to the idea of seeing in black and white.  If we can train ourselves to look at a colour scene and convert it in our brains to black and white using the different colour filters we can begin to see the contrasts that exist and what visual interest may be available to us.  This takes time and practice.  You can practice by converting some of your existing colour images using any of the available methods.  Do a straight Image>Mode>Greyscale conversion and see what happens.  Then switch it back to colour and use some of the other methods available.  The Channel Mixer lets you adjust Reds, Greens and Blues.  The Black & White tool in Photoshop lets you adjust those three plus yellows, cyans and magentas.  The colour adjustments in Adobe Camera RAW and Lightroom give you all of those plus oranges and purples.  My personal belief is that the more colour adjustment controls you have available, the better your black and white conversion will be because you have the ability to separate tones more.  Now, that is a general statement not an absolute so take it as just that.  Experiment with adjusting the colour sliders up and down to see what happens to the individual colour you’re adjusting but what also happens to other colours.  Pay particular attention to yellow and see how  much it really does affect greens.  As you experiment, you’ll begin to train yourself to be able to see in shades of grey.  This will help you tremendously when you’re out in the field shooting.

Another way you can go about this is with your camera.  Many digital cameras have a black and white or monochrome mode.  You can use this to get a greyscale JPEG of your image.  Many cameras that allow you to shoot RAW + JPEG allow you to capture the JPEG in monochrome and still have the colour RAW file to work with.  This lets you get a representation of your image in black and white but still affords the ability to adjust it yourself from the RAW file.  To be honest, the monochrome/greyscale modes in most digital cameras aren’t that good.  They offer a canned conversion that relies on a single formula.  Chances are, in most cases, it’s going to give you that ‘muddy’, low contrast image that isn’t overly appealing.  But at least it gives you a representation.  Some cameras allow you to mimic the use of colour contrast filters in greyscale mode.  These work a little bit, but not nearly as well as the filters on black and white film.  Again, it will give you a starting point, a representation of your image in greyscale and you can work with the RAW file to give you something better.  If your camera shoots JPEG only and you want to capture in greyscale, your options are a bit more limited, unfortunately.

So, train yourself to begin seeing in shades of grey and I’d be willing to bet your black and white photography will start to improve pretty quickly.

How do you see in black and white?  Happy to receive feedback and to hear of success stories.



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