Sometimes you take a photograph that although it looks great in color, it has a certain quality to it that would make it look great in black and white. Depending on what version of Photoshop you use, there are a few methods to convert your color photos to black and white. Note that one of the methods that I will show you requires Photoshop CS3. If you don’t have version CS3, then follow one of the other methods.
1. Black & White Image Adjustments Mode
The first method requires Photoshop CS3 and is a new feature to this version. Now with CS3, there is a function built in that allows you to convert photos to black and white. To access it, simply go to Image->Adjustments->Black & White. Once you do that you’ll be presented with a dialog box that looks like this:
As you can see, there are various sliders there that you can adjust. Each one will adjust the amount of gray tones for that particular color that is present in the image like the Channels Mixer. Moving the slider to the right will lighten that color, and moving it to the left will darken that color. If your image does not contain a lot of a color, then adjusting that slider will have little to no effect on the image. By default, Photoshop will try to choose a basic neutral gray when you first choose the Black & White option. This may be fine for some images, but try to adjust the sliders and take notice of what changes in your image.
One thing you should note is that if you mouse over your image, the cursor will change to an eyedropper icon. If you click on a part of the image, the channel that is most dominant for the spot you clicked will be highlighted. This is handy for determining what slider will lighten or darken that part of the image. You can even click and drag left or right on a part of an image to automatically adjust the slider that is relevant to that part of the image. Alt-clicking will reset the slider for that color.
You may have noticed the drop down box at the top of that dialog. That menu contains built in presets for converting a photo to black and white. Try using different ones, as the effect will vary depending upon what colors are in the image you are using.
Lastly, the Tint checkbox at the bottom of the dialog allows you to tint an image as well as convert it to grayscale. You can adjust both the color of the tint (the hue) and the saturation (the amount of that color). You can use this to quickly create your own sepia toned photos, or any other kind of colored effect like that. The best advice I can give would be to experiment until you get a result that you’re happy with.
2. The Channel Mixer
The next method can be used by most versions of Photoshop, so if you don’t have CS3, then this is a good method to use. Although it doesn’t offer as much control as the Black & White image adjustment, it is probably the next best thing. To access it, go to Image->Adjustments->Channel Mixer. This will bring up a dialog box that looks like this:
The Channel Mixer will adjust the red, green, and blue values as well as the grayscale values to a particular output channel. Now it’s important to note that the sliders will affect only the output channel you currently have selected. This can have varied results if you’re working in color. For our purposes, you will be adjusting the values to the gray output channel. To do this, you must make sure that the Monochrome box is checked.
Like the previous example, there is a preset dropdown at the top of the dialog box. You can experiment with this to see if you can achieve the results you want. Otherwise, you can adjust the sliders for each of the red, green, and blue values, as well as the grayscale values. The Constant slider will adjust the grayscale values by adding more black or more white to the image. A value of -200% will give you a completely black image, while a positive 200% value will give you a completely white image. Again, depending upon what colors are in your image, you will need to adjust the proper channel. Just move one slider at a time and see what colors are affected. Clicking and dragging the cursor within your image will show you the grayscale value of that color in the Color Palette on the right side of your Palettes menu.
3. Desaturation
Desaturating an image means to reduce the saturation of a color within the image (the amount of a particular color). This is one of the least effective methods, as it leaves you with an image that is very neutral gray in tone, with very little contrast between the shades of gray. However for the sake of completeness I will show you this method, of which there are actually two ways to do it.
The first way to desaturate an image is with the Hue/Saturation Image Adjustment. To get to it, go to your menu and choose Image->Adjustments->Hue/Saturation:
To convert an image to grayscale using this method, simply drag the Saturation slider all the way to the left. This will completely desaturate an image, leaving you with simple gray tones. Note that the dropdown box must be set to Master for this to work. It is possible to desaturate each individual channel and you can get some interesting effects this way. However, if your goal is to just convert an image to black and white, then it must be set to Master.
The other way to desaturate an image is to use the built in Desaturate command. You can find this under Image->Adjustments->Desaturate. Again, this is the same as using the Hue/Saturation adjustment and moving the slider all the way to the left while having the Master channel selected.
4. Grayscale Mode
The last method to converting an image to black and white is to use Grayscale Mode. This method will yield the same average results as the Desaturation method does. In order to convert an image to grayscale mode, simply go to Image->Mode->Grayscale. You will get a pop up warning you that you will be discarding all color information. Click Discard and you will now be in Grayscale mode. Note that the difference between this method and the Desaturation method is that in this method you will now be in Grayscale mode. This means that even if you choose a color from your palette, it will be that color’s value in grayscale when you use it (with the brush tool, for example). In order to go back to working in color, you will need to change into one of the various color modes again by choosing Image->Mode->(color mode).
So there you have it! As you can see there are quite a few different ways on how you can convert a photo from color to black and white. Some are obviously better than others, but feel free to experiment with each one so you can familiarize yourself with them. As always, if you enjoyed this tutorial or if you have any questions, please leave a comment and I will answer you as best I can.
