My team and I are making our notebook and are experimenting with the format and layout, and we were wondering whether you think that it’s better to have a white background with black text or a black background with white text? (Also bearing in mind that we might need to print it out for some events)
We are using Google slides.
Thanks 
White.
If you have a black background, you will be using A LOT of black ink when printing.
Personally, I would say white background with black text as it is easier to read and much easier to print out.
In my org/area there have been some issues with printing being weird, which could be due to a different colored background (we used green). Therefore, I works just stick with white. Also, I have heard troubles with color/format of digital submissions, so I would use white to prevent things getting messed up. Also, ink can get expensive, so I would use less if possible.
Personally, I think that a white bg looks more pleasing, and as others said, uses less ink.
You could create a copy of the notebook and inverse the colors to help with the ink problem.
As a judge, white paper with black letters please. Use this font
not comic sans 