Here is a trick that I use. Paint the instruments white. Let set for at least two days to cure. Then paint black and wait about an hour. Use a wooden dowel, about the same dia as the instruments. Spin the dowel around a few times over the instrument to rub off some of the black paint over the raised areas. It only takes a few spins and soon you will have just the effect you are looking for.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.