Open the photos you want to edit with your photo-editing software. If your photos were taken by a film camera, you will need to scan the negatives or prints into your computer first. Scans don't always look as good as the originals, so you may need to spend some time tweaking them before you are ready to proceed.
Select your photo editing software's "black and white" setting. In Photoshop, it's in the menu under "Image/Adjustments/Black & White..." You'll notice the tool has a set of sliders labeled with color names. We'll get to that in step 3.
If you are using iPhoto, select a photo, click "Edit," then click "Effects," and then "B & W." In simple editors like iPhoto, black and white conversion has only two settings: on and off. Just click "Okay," save, and you're done.
Convert the image to grayscale if your photo editor has no dedicated black and white tool. That will throw out all the color information. Tweak the grayscale image by changing the brightness, highlight and contrast settings.
Tweak the color channel settings. Most full-featured photo editors such as Photoshop will have sliders allowing you to control the brightness of different color ranges when converting to black and white. These settings allow you to bring out detail that may appear too dark or too light when using the default settings.
For example, increasing the amount of red will increase the brightness of parts of the image that were mostly red in the original. Likewise, decreasing it will make those parts darker.
Click "Okay" and save once you have the photo looking the way you want it.