This is a basic tutorial, from http://www.tutorial9.net/category/tutorials/photoshop-tutorials/ which has a lot of tutorials for photoshop and other manipulation programs.
I found it to be helpful in creating a more visually appealing infographic. It would not take out the color out of your text or picture, so it wouldn’t have to be gray. Its really simple, but when I was browsing through info graphics, they were all in solid colors and blended in together. The ones I remembered had something eye catching, even if it was as small as this. You could also add it to charts/graphs to differentiate the bars or sections of a pie chart.