I had this exercise on a test the other day and I still don't know how to solve it. Being given the image below, I have to say what's the type for each spectra, absorption or emission. I didn't find any answers about the differences in representations on the internet so I've come here to ask for help.
Not a well formed question, see the colored full case
of the hydrogen emission and absorption.
If it were a colored image you were given the emission liines are on a unform black background (no continuous frequency light coming from the sample of hydrogen), in contrast there is a full spectrum of light thrown on the hydrogen in order to see the lines of what is absorbed.
The black and white you show could only be emission because there is no grey in the picture.