I am having trouble sourcing gloss enamel paint. I am restoring a small patch on one of my signs and Humbrol don't make CMYK colours and too small sizes anyway. Keeps enamels are no longer made. Even Google doesn't turn up many suppliers with a good range. With Cyan, Magenta, Yellow and Black I can make most colours but the well known dark royal blue is tricky - its got a hint of magenta in it. Thanks if you know. Fred Kite

If its a small patch of dark blue required, such as a chip repair, try Winsor and Newton Cobalt. This dark blue ink needs to be built up in layers and allowed to dry between each layer. Otherwise I use car spray paint.
Cheers Richard