You would need to take a number of factors into account in this instance. Firstly, it depends on what you’re planning to overlay. Has the surface you’re spraying onto already been painted? If you’re spraying onto plastic for example, the surface should always be more highly pigmented than the subsequent coating. Undercoats are highly pigmented; clear lacquers don’t contain any colour pigments. The best layering structure is therefore primer – coloured paint – clear lacquer. The lacquer won’t adhere to smooth plastic surfaces. In order to prevent paint from flaking off, the item should always be treated in advance with the edding plastic primer.