I do like having linework. It lets me have a clear
guide line for where things go as I'm painting, pencil can get too
easily lost under the paint and then I make a lot of mistakes once
that happens, mostly in the proportion of facial features. And
especially with watercolour it can feel a bit hard to understand the
end result without some line art in there somewhere, landscapes are
fine but people can end up looking a bit hazy.
A lot of the time though it's just too extreme a
contrast to the colours it's bordering if that makes sense. For
example if I was to draw blue water with black line art then it makes
it more solid than I'd want it to be, it's even worse for really pale
things...drawing the sun, a nearly white thing, should probably not
have such a solid black outline.
Unfortunately I only bought the 8 colour pack, and
one of them's black. So other than the red their all pretty dark
colours...still doesn't help greatly with drawing pale things.