Avoid the Convert to Grayscale Mode “Crutch”
Some photographers may question why you would want to convert a color picture to black and white in the first place. Well, sometimes your subject matter will call for that type of rendition. The most common use is for portraits. Some digital cameras save black and white (or sepia) type images in an RGB (red, green, blue) mode, but not all will. In the end, the choice to convert any color image to black and white becomes a personal one. It is what suits you that counts. I’m going to explain some different options to you, so you will be able to have more control over the final output of your images.
While the action “Image>Mode>Grayscale” is easy to use, it doesn’t always produce an optimal result, even after adjusting your contrast, shadow and highlights. There are a few other customizable options you can utilize when changing a color photo to black and white that will more often produce spectacular results. Converting an image to grayscale in Photoshop and similar programs will often drop the RGB color mode. That’s okay, because you can reconvert an image back to the RGB mode after you convert it to a black and white or sepia image.
To help further my explanation, I have chosen a digital color image of the famous St. Louis arch.
Note that prior to converting an image to black and white, some photographers recommend adjusting the colors automatically or manually prior to doing any conversion. Also, you should save the file you want to work with under a different file name. I usually use the term “edited” at the end of my file names.
Here’s the same image after applying the grayscale mode:
Now, there are two main methods of converting color images to black and white.
One is “Desaturate,” which is usually under “Image>Adjust>Desaturate.” The second method is “Image>Adjustments>Channel Mixer.”
Here’s the image using the “Desaturate” control:
My experience has been that the desaturate function tends to give a lighter result than the grayscale function.
When you use “Image>Adjustments>Channel Mixer” in Photoshop, a dialog box opens and you should check the “Monochrome” option (usually in the lower left corner). Next, adjust the sliders to suit your image. Make sure that the totals of all percentages equal to approximately 100 percent. You can have negative values here as well. For the next image, I simply used the red channel default, which is 100 percent. The other two colors (green and blue) were at zero. You will note that this method offers a darker result.
Of course, after you have applied any of the above techniques, you can always reapply any of the auto-level, auto-contrast or the various manual adjustment tools to vary the contrast (highlights and shadows) of any of your results.
But, keep in mind, that doesn’t always work to your advantage. I applied the auto-contrast tool to the fourth image and it became much darker and hid details in shadow areas. This is not what I would prefer.
Well, I hope this information was useful to you. The joy of photography is not only in taking great pictures, but in the use of the additional tools available to us that we can use to make our images better.
~ Mike Clipka