For the lettershapes themselves it won't likely be a matter of "printed area", depending on the news paper it will be printed at a far lower dot grain density than your average print product.

There are although numerous things to consider when designing a font for small printed copy, like how tight you can make a corner before ink would start to trap in it and bleed over the detail.

But there are many aspects of creating a full font family that make it a huge amount of work - not only do you need to fit all supported characters to different weights, essentially re-drawing the glyphs for every weight to make them balanced within their shape. You'll also have to do the kerning, tweaking individual spacings for all possible letter combinations at every weight. And that is all after having created & perfected every shape of every glyph to work together and have a distinguishable look and fashion.