[How to copy a color?]

OK, thanks a lot !

[How to copy a color?]

Hi, I'm new here. I have been reading, and reading, and searching, but I can't find the answer to my problem.

When I have a picture of my daughter, wearing a blue dress and I want to add some text in blue, how do I do it to have the same shade of blue as her dress ? Is there a way to sort of copy a color ?