Convert To Black and White

A quick glance through any photography or fashion magazine, or at the photos on social websites like Flickr, confirms that black and white photography is as popular as ever. With the coming of digital though, one important thing has changed. In the days of film photography, you shot on black and white film. Now, with digital cameras, you take photos in colour and then convert them to black and white.

How to Convert a Color Photo to Black and White

Converting to black and white digitally has a number of advantages. With film, the black and white conversion essentially happened at the time of shooting. If you wanted to change the nature of the black and white conversion, you could only do it by placing a coloured filter on the lens (a red filter, for instance, makes blue skies much darker).

Now, by starting with a colour photo and converting it to black and white in Photoshop, you have complete control over the conversion. Darkening a blue sky is easy, once you know how, and you can decide exactly how dark you want it to be.

The best cameras for black and white photography are digital SLRs. For the best possible conversion, start by shooting in RAW. Then, in your RAW conversion software, output the photo as a 16 bit Tiff file. 16 bit files have a lot more information to work with than 8 bit files, which makes for a better conversion with smoother tonal graduations.

                     

Black and White Conversions

Photoshop and Photoshop Elements offer both destructive and non-destructive black and white conversion techniques. Destructive methods are ones that can't be re-adjusted afterwards. Once you've made the conversion, the only way to change it is to undo the conversion and start again.

Non-destructive methods use Photoshop's adjustment layers. The changes that you make to your photo are stored in a layer, and the original photo remains unchanged underneath. Then, when you're done, you flatten the image and it's as this stage that Photoshop makes all the changes to the photo permanent. You can edit the conversion at any time before flattening the image by clicking on the adjustment layer's icon (circled).

Non-destructive photo editing is always better than destructive editing. The destructive methods are included here for completeness.

These instructions are for Photoshop CS 3 and Photoshop Elements 6.0. Other versions will be similar.

Convert to Greyscale (Destructive)

The simplest black and white conversion method, converting to grayscale discards all the colour information in the photo.

Photoshop CS 3:

1. Image > Mode > Grayscale
2. Click ‘Discard'

Photoshop Elements:

1. Image > Mode > Grayscale
2. Click ‘OK'

Pros: Quick and easy.

Cons: You have no control over the conversion.

                         
Use the Hue/Saturation Tool (Non-destructive)

This method gives exactly the same result as converting to grayscale. The only advantage is that it's available as an adjustment layer, and can be used as part of a non-destructive editing process.

Photoshop CS 3 and Photoshop Elemennts:

1. Layer > New Adjustment Layer > Hue/Saturation
2. Click ‘OK'
3. Move the saturation slider all the way to the left (-100) and press ‘OK'

Pros: Quick and easy and and can be applied as an adjustment layer in both Photoshop CS 3 and Elements 6.
LAB Color Method (Destructive)

This technique converts your photo from RGB mode to Lab mode, which records the brightness and colour values separately, then discards the colour information leaving a black and white image. It's not available in Photoshop Elements.

Photoshop CS 3:

1. Image > Mode > Lab Color
2. Go to the Channels window if it's already open (if not go to Window > Channel) and select the Lightness channel
3. Image > Mode > Grayscale
4. Click ‘OK'

Pros: Gives a better black and white conversion than the convert to grayscale and hue/saturation methods.

Cons: Destructive editing process that doesn't give you much control.

                      

Gradient Map (Non-destructive)

The gradient map tool maps a black and white gradient to the brightness values of your photo. Dark areas become black or dark grey and highlights white or light grey.

Photoshop CS and Photoshop Elements

1. Press ‘D' to reset the foreground and background colours to black and white.
2. Layer > New Adjustment Layer > Gradient Map
3. Click ‘OK'
Pros: Quick and easy non-destructive black and white conversion
Cons: No control over the conversion
             

Channel Mixer (Non-destructive)

The Channel mixer is the first black and white conversion tool listed here that begins to use the full potential of the information contained in the colour photo. Colour photos have three colour channels; red, green and blue. These primary colours combine to make the millions of colours in your photo.
The Channel mixer conversion method lets you adjust the ratios between the red, geen and blue channels. Lightening the value of a channel lightens colours close to it on the colour wheel and darkens the colours that are opposite it. Increase the value of the red channel for instance, and you'll make the red tones in your photo lighter, and the blue ones darker. This has the effect of lightening skin tones and darkening blue skies.
The Channel mixer is the digital equivalent of black and white photographers using colour filters. Setting the brightness of the red channel to 100% gives the same effect as using a red filter on the lens with black and white film. It's not available in Photoshop Elements.
Photoshop CS:
1. Layer > New Adjustment Layer > Channel Mixer
2. Tick the monochrome box.
3. Move the Red, Green and Blue sliders to the left and right to lighten and darken different tones in the photo. The total of the three sliders should be 100% at all times.
4. Click ‘OK' when you're done.
                

Photoshop Elements: Convert to Black and White Tool (Destructive)

This method is a simplified version of Photoshop's Channel Mixer adjustment layer. It's only available in Photoshop Elements and isn't available as an adjustment layer (so it's destructive editing). Having said that, if you can live with the small previews, it's a very flexible black and white conversion technique.

Photoshop Elements:

1. Enhance > Convert to Black and White
2. Move the colour sliders to the left and right to lighten and darken the corresponding tones. Use the Contrast slider to compensate for changes in contrast. You can also select a preset style from the menu on the left. Click ‘OK' when you're done.

Pros: Flexible black and white conversion using the colour channels.