How do you darken writing in a picture of a old letter?

I took a picture of a letter my dad wrote while he was in Vietnam. You can barley make out the words in the letter. I was wondering how I can darken the words on the photo of the letter from my phone. All I have is the photo I took of the letter. I know there has to be a app or something to be able to darken just the words.
Asked Mar 08, 2016
adobe Photoshop or something similar to it would be best.
Answered Mar 09, 2016

TIP: If it's not your answer to this question, please click "Leave a Comment" button under the question to communicate with the question owner.