Don’t throw away those pixels!
This is very basic and most of you reading this post already know this, but for the new folks, I want to help you properly convert your images in Photoshop to monochrome.
Don’t import a color image and select the IMAGE > MODE > GRAYSCALE command to convert it into black and white. If you do that, you will literally throw away two thirds of your valuable data that you can’t get back later! You will also end up with a flat, drab-looking image that will make a turkey puke.
Instead, use the IMAGE > ADJUST > BLACK & WHITE command (there are other ways to do this with adjustment layers or the channel mixer but for the sake of this post I’ll keep it simple.) If you use the appropriate command, your image instantly turns black and white but retains all the original data.
This tool essentially allows you to apply filters to the image much the same way you would in the field. For instance, want more contrast in your image? Just add some red. Start by clicking the monochrome box and you get black & white. The default settings are shown below. It usually looks pretty good and allows you to keep more shadow detail than using the traditional mode switch from RGB to grayscale. You can experiment with the sliders in real time to see which colors bring out the best in your image. For example, if you shot a flower in a heavily green forest and want to bring out the foliage, more green will be in order. Experiment and when you have it the way you like it, save it.
If I improperly convert the eagle photo featured in this post to a B&W .tiff file using the grayscale command, the file size is 35.5MB
If I properly convert the eagle photo featured in this post to a B&W .tiff file using the BLACK & WHITE command, the file size is 106.4MB. As you can see, the proper conversion gives me much more data to work with in post and a larger file size for printing. The best practice is to convert using the IMAGE > ADJUST > BLACK & WHITE command and then if you need to adjust the image in post, you will get a better result because you have more pixels to work with. You can always make a smaller file later, converting to .jpg if you need to.
Compare this method with using the mode switch to grayscale and I’m sure you will find that the results are punchier and more pleasing.