I need to change this image's color background to white, because this takes up too much ink. I have tried to change the background to white and keep the text/map. It's for a National History Day project. I have used Autodesk Pixlr Editor and Autodesk Pixlr Express. I have only used online programs, because I have a Samsung Chromebook. Here are the results I got in the same order of programs listed above. I think Pixlr Editor is the best, but my dad said that lots of it will be grey, so still lots of black ink used to stimulate the grey. (I couldn't post the result of Pixlr Express, because I need at least 10 reputation to post more than to links.
If you're using a Mac, open the image using Preview, and select 'Adjust Color' from the Tools menu. Drag saturation to the very left to make it black and white, then click "Auto levels". Try playing with other settings to get what you want.
If you're using Windows, download Paint.net, and follow a similar approach.
I was able to get a reasonable result with this: