Join Date: Aug 2017
Location: Perth, W. Australia
Had a bit of experience in painting, Touching up texture paint is not easy, but there is a way if it's very small.
First, make sure it's the same color, well, black should be black, but in auto paint world not all blacks are the same.
just use a small can of basic flat black, don't use spray cans, the paint is too thin to get a good texture.
If it's a really course finish, there are flat black wrinkle finish paints that could work also.
Next, don't use a brush, texture finishes on walls use a course wool roller, obviously not possible on a triple tree.
Apply using a cotton bud in place of a brush, and dab the paint on the spot. brushing smooths the paint out.
The rest is trial and error, and depends on, thickness of paint, if it's wet or tacky etc. etc. just try it on a piece of scrap and you will see the different 'grade' of texture you can get.
Usually you may have to cover a complete section, corner to corner in a sense to hid the different finish. Then a piece of larger cotton wool would be better.
hope this helps,