Pixiq

Better B/W from a color image. Easy!

Too many photographers simply create a grayscale image when they really want a black and white photograph.

Simply changing your image files to a grayscale in Photoshop will kill your chances of making critical tonal adjustments. A grayscale image is an image that only has 8 bits of data or a single channel. An RGB Color image contains 3 channels that are 8 bits each for a total of 24 bits. To say that you have an 8-bit (actually 24 bits or 8x3 channels) image means that you have Red, Blue and Green channels. It is these three channels that can be used to produce great Black and White results.

The goal of using these channels is to create a difference in tonal values between objects in the scene for the purpose of better defining the subject.

In most cases, if you use your cameras black and white function to produce a black and white image you are actually creating an RGB color image where the saturation has been reduced to tones of grey. This happens at least on the camera display. However, in most cases, the actual image is saved as a color file and therefore the image contains all of the RGB color data. This is especially true for RAW format. Most cameras save the RGB data with the file. However, you might want to check your manual just to be safe.

On some older cameras, depending on the camera mode you are using or the “art effect” you use, you might actually be changing the file to a grayscale image. Although it may have RGB channels, the actual colors are no longer available for use. Without the color information, you will not be able to produce the proper contrasting tones in your b/w image. The value of having all colors in your “black and white” image is that the colors can function in a similar way as filters function in black and white photography. Any RGB color file can be adjusted into a black and white image. However, I tend to save my files as RAW so that I am sure to have all of the image data that was captured.

To make a good Black and White image in Photoshop, you will need to use an adjustment layer.

Here you see the image layer on the bottom and a black & white adjustment layer has been added above it. The beauty of an adjustment layer is that the original color image is not actually altered unless you happen to flatten the file and save over the original image on your disk.

In the black & white adjustment layer palette there are a series of sliders for red, yellow, green, cyan, blue and magenta. Moving these sliders will alter the tonal value of the colors contained in the original color image. If we move the red slider and watch the saddle area we can make it darker or lighter. Likewise, if we move the blue slider, we will see a change in the blue areas. The idea is to create a separation between the two adjacent tones in order make the black and white tonal values match the values in the original image. In the original color image, I see the red as lighter and brighter than the blue and therefore I can change values with the sliders to make the red lighter than the blue. 

To take advantage of the color information in your image you should carefully adjust the color sliders in the black and white adjustment layer palette. If you open a color image and duplicate the file, you can make alterations using the sliders using the second image as a reference to see the original colors and the effects of using the adjustments.

Here you can see that the red saddle and the blue horse have definite tonal value and contrast differences. The horse on the right however shows that the red and blue tones need separation when turned into a black and white image. The tones are two much alike in value and contrast.

This image shows a better separation of the saddle and the blue horse as a result of moving the blue slider to a darker position and the red slider to a lighter position.

In this image the values for the vegetation and the flowers have been altered to produce a tonal differences between the flowers and the grass and the green plants and the rocking horse. In some cases you may actually want to bring certain tones closer together or even have them match.

The real value of filtering is realizing that all of the colors in your scene are not pure colors. Most things such as green grass, blue sky and red flowers are actually made up of a mixture of colors. A red object may have a small amount of green or small amount of blue to give it a particular shade of red. A blue sky has some red and some green mixed with mostly blue depending on the time of day and other factors. A white cloud is made up of nearly equal amounts of red, green and blue. Cyan is a mixture of blue and green so you would need to use two sliders for a cyan that needs adjusting. Knowing this, you can use the rest of the sliders to make additional adjustments within a color.

Here is a tinted result which is still a bit too dark in some areas and requires some other image manipulations such as dodging and burning.

This is the final image after making tonal adjustments,tinting, dodging, burning and sharpening. Save the file under a different name.

The best thing about doing it this way, is that we still have all of the RGB data which will allow us to make additional tonal adjustments if we need them.

Black and White is pretty easy to do provided you don’t throw away the color.

Please read my other posts at pixiq.com. 

© John Neel