If it is a Hummer with a single desert color, only two kinds of desert color pigments and white water fill (backing) are needed, and two kinds of desert camouflage can be used if Sansha camouflage is used. These commonly used colors are sold directly.
Is this your first painting? The concepts of pen-spraying and hand-drawing are completely different. Of course, if you have enough money, you need pen spray (double-acting, single-acting, siphon, trigger, which is suitable for pen spray according to your personal level), air pump (linear, motor, diaphragm, expensive to import, cheap to make in China), nitrolacquer and solvent (diluent paint/cleaning spray).
If it is hand-painted, you need to prepare flat brush, pigment, solvent (nitro, enamel and acrylic can be selected), water-based acrylic is recommended for hand-painting, because too much oily pigment will deteriorate ABS parts), slow drying agent (added to pigment, it can slow down the drying speed and eliminate pen marks) and matte transparent pigment spray. In fact, Gundam marker produced by GSI· Cleos Company can also be used for pen drawing.
In addition, if you think the effect of pen-and-ink painting is really bad (of course, it is not as good as painting, and the paint film of pen-and-ink painting is very uneven. Generally, professional producers only use pen-and-ink painting when doing special effects or painting some tiny parts. If the economic situation permits, they can also choose painting produced by GSI or Tamiya. The price is slightly higher, but the effect is very good.