The one issue I ran into with this portrait of Taemin was being consistent with my colour mixing. Skin tones are quite difficult to mix and I found I'd often put down a whole layer when I only intended to work on a small area simply because the tones didn't match. I came across a very handy tip online. In order to keep the same mix (as it may dry out overnight or in a day or two), after working with it, put it in a small plastic bag and seal. Snip a corner and then squeeze out what you need the next time. It did work but it does also dry out, although more slowly, so it won't stay usable indefinitely.
I've experimented with different skin tone mixes since I painted this but for this one I stayed with a formula I found online - Cadmium Red, Cadmium Yellow, French Ultramarine, Burnt Umber and Titanium White. Many of these colours are Winsor & Newton 'Winton', that is, their less expensive range. Many of the colours are excellent but I have noticed some that are not very vibrant or are too oily - Cadmium Red in the Winton range just doesn't compare to the 'Artists' ' range at all and Winton Raw Sienna is so oily I found it useless.
Here, however, I've used Winton Permanent Green Light in the background and I love this colour. I think I have mixed it with French Ultramarine Blue to shift it slightly. His jacket is almost pure Fr Ultramarine Blue and mixed with white to create the slight sheen. His hair was a bit of a challenge to mix but I found a combination of black, white and yellow to create that cool beige.
I still have the tape on the canvas in this photo. I put masking tape around the edge to keep it clean because with this very small canvases I often work on them holding them in my hand rather than on an easel. I'm pleased with the result but I do need to work on mixing those skin tones!