"Creating Black And White From Color"

Black-and-white photography is as powerful today as it was when color photography was just a distant dream. A different set of skills is required when working with black and white, as the absence of color means the interplay of shape and contrast must work harder to tell the story or set the mood, but when it works, it's very effective.

Some cameras have a dedicated black-and-white mode, but even if yours doesn't, you can still work in black and white. In fact, it often works better to shoot in color and convert later on. Photoshop offers a breathtaking array of techniques for converting color to black and white (or more correctly, grayscale), and these enable you to control the process with a degree of finesse that would be difficult to match in the field.

Method 1: Desaturation
This shot was taken early one winter's morning in New York. The sky had a dramatic quality and there was a fine haze rising to meet the colder air at higher altitudes. The image works well in color, but it also has potential for a striking black-and-white impression of the city.

STEP 1
The most obvious way of converting color to black and white is to convert the mode to grayscale (Image > Mode > Grayscale). This is okay, but there are better alternatives. The first is desaturation—removing the visible color information but maintaining the RGB status of the file. This means that if you wanted to add a tint later you could do so without having to change color mode again. Go to Image > Adjustments > Desaturate (or press Ctrl/Cmd + Shift + U).

STEP 2
The problem with desaturation is that it often delivers a flat, uninspiring rendition. We can improve this, however. Analyzing the photo, we need to strengthen the texture in the sky by darkening the shadows and midtones, but the buildings below need a general increase in contrast to remove the haziness. It's best to treat the sky and the buildings as separate entities. Make a feathered selection of the sky, using the natural division of the rising dark haze as a guide.

STEP 3
Press Ctrl/Cmd + J to copy and paste the selection to a new layer, and rename it "sky." Add a Levels Adjustment Layer to it, making sure the two layers are combined as a clipping mask. To bring out the sky texture, drag the Black and Gray point markers to the right as shown.

STEP 4
Depending on the amount of feathering and the position of your selection, you may see a dividing line after the Levels adjustment has been made. This is easily removed by adding a layer mask to the sky layer (set to Reveal All) and painting on the mask in black until the edge disappears. Work carefully with a soft brush at a low opacity and the result should look something like this.

STEP 5
We could use a Levels adjustment layer to add contrast to the buildings, but there is an alternative route. Go to Layer > New Adjustment Layer > Curves to add a Curves adjustment layer to the background layer.

STEP 6
Applying the curve shown increases midtone contrast, at slight expense to the highlights and shadows. This diminishes the haziness in the area of the buildings. The final image is far more striking, and much closer to what the photographer originally envisioned.

Method 2: Single Channels
In traditional black-and-white photography, color filters are often used over the lens to create dramatic contrast, the reason being that hues that are quite different in real life can merge into one when seen in grayscale. For instance, a strong blue sky with white clouds can appear weak in a black-and-white photograph. A red filter placed over the lens will darken the blue sky, making the white clouds stand out, because the red filter blocks the blue color waves more effectively than it does colors that are nearer to red. As a result, a red car in the same scene would look lighter. In short, when a color filter is used in black-and-white photography it lightens elements of its own color and darkens elements of its complementary (opposite) color.

We can see this principle in action in Photoshop and use it to create some very different styles of black and white. In this photograph of a mountain stream in the French Alps, the combination of strong contrast and lighting with the sensual curves of the glistening snow makes it an ideal candidate.

STEP 1
Go to the Layers palette, click the Channels tab, then click on the Red channel. The image seen will resemble the result that a red filter over the lens would have generated, with a darkening of the blue-tinted areas that makes for a moody, sophisticated image. For comparison, click on the Green channel. The result is similar to the Red channel but less pronounced. Finally, look at the Blue channel — it's lighter, since most of the image is blue.

STEP 2
Without doing any work, we have three different ready-made black-and-white effects. All we have to do is choose our preferred option: dark and moody. Click on the Red channel. The following keyboard shortcut sequence makes light work of turning it into a new document:

• Ctrl/Cmd + A (selects all)
• Ctrl/Cmd + C (copies the selection to the clipboard)
• Ctrl/Cmd + N (creates a new document of the same proportions as whatever we have on the clipboard. The document will also be a grayscale as we only have one channel selected)
• Enter/Return (to confirm the settings. No changes are necessary)
• Ctrl/Cmd + V (to paste the contents of the clipboard to a new layer)

That's all there is to it. Use Levels and Curves if you want to fine-tune the result.

Method 3: Calculations
Using the channels straight out of the box works brilliantly, as long as one of the channels gives you the desired result. If not, some manual mixing is the best solution. The Calculations command is your best resort — don't let the name put you off, as no math on your part is required. This image of the bell and cross is our next challenge.

STEP 1
Checking the channels shows that the Red channel offers the best contrast between the sky and white cross. However it's not very strong and the range of tones isn't varied enough to create a strong result.

STEP 2
Keep the Red channel active and go to Image > Calculations. Because the Red channel was active, the Red channel appears in the Calculations dialog box. Source 1 and 2 are set to the same document, layer, and Red channel, which means they will be combined for the calculation to take place. The blending drop-down is set to Multiply. This works in exactly the same way as the normal layer blend modes. Multiply will darken the image, but based on the red channel. Therefore blue elements or elements with a blue cast will become darker than other elements. Set the Result drop-down box to New Document to create a new multichannel file based on the calculated result.

STEP 3
In this case, multiplying the Red channel works perfectly. The blues are darkened, creating this bold final image.

Another Option
For a slightly less dramatic result, try combining the Red and Green channels, again using the Multiply blend mode. The difference is subtle, but it demonstrates the fine control you have using this technique.

Method 4: The Channel Mixer
Staying within the context of mixing and calculating channel values, another powerful option is the aptly named Channel Mixer. This command allows us to mix the values of each of the channels, providing us with an enormous variety of combinations. In this shot there should be no mistaking the flower from the leaves and stem. However, after desaturation the greens and pinks merge.

STEP 1
Make sure the RGB composite channel is active, then go to Image > Adjustments > Channel Mixer. Enable the Monochrome checkbox. Changing the percentage values for each of the Red, Green, and Blue channels will dramatically influence the image. Traditional black-and-white photographers might consider using a green color filter here, as this will lighten the greens of the foliage and darken the pink flower (pink is almost complementary to green). To emulate this in the Channel Mixer, change the values by boosting green and diminishing red.

STEP 2
The result is very different from the original desaturated version. We can use the idea of a color filter as a guiding principle here, or just adjust the settings by eye. The main thing to keep in mind is that the total percentage value of all channels combined should be roughly around 100% with a variance of 20% or so. Your eyes will tell you this as you experiment — any extreme value above or below 100% simply won't look good.