First, I decided to reduce the palette into 14 colours, leaving the 15th for later under the assumption it’s probably going to be a neutral mid-tone.
Then I divided the palette into two main groups (A & B) 7 colours each – shadows and lights. I decided to further subdivide the existing groups; requiring me to subtract one colour from each group, so that the new groups remain balanced and even.
Under the shadow group (A), the two major groups (1-3 & 4-6) each represented a different shade of shadow with one being darker than the other, and the remaining colour (13) which is also under the umbrella of “shadow”, I decided to categorise as “black”, basically being the darkest colour in the palette.
Very similarly, the light group (B) had two major groups (7-9 & 10-12), with one being darker than the other, and then the remaining colour (14), I categorised as “white”, being the lightest colour in the palette.
Dealing with the colouration of the lights and shadows I went with a pretty classical approach, I first deiced that the shadows should lean to blue and the lights lean to yellow , imitating the blueish colour of shadows from the sky and the yellowish tint of lights from the sun, as seen in nature; doing this both unifies the entire palette , and creates a strong complementary contrast between the lights and shadows.
Knowing this, I also knew that the yellows technically should be more desaturated than other colours in the shadow group, and that blues should be more desaturated in the lights group.
Additionally, the shadows and lights followed the simple idea of shadows being greyer, and lights being more saturated, which makes the colours glow somewhat.
I ended up going with 3 base colours with different alternations in all the subdivided groups, those colours being blue, red and green, each colour respectively being generally darker than the one after.
The reds in the shadows group (1 & 4) ended up becoming more akin to purple, and the reds in the lights group a lot more saturated (7) and yellowish (10). The blues in the light groups essentially became cyans (8 & 11), or greener. The greens became lime coloured (9) and yellow (12).
Following the logic established before about the colouration of lights and shadows, the darkest colour (13) leans to blue, and the lightest (14) to yellow.
With the remaining colour (15), I went with a brownish one due to it being an important colour when it comes to nature, and also to give the yellow a proper shadow colour, and to balance the transition of the orange slightly to the shadows.
Some of the weaknesses that are quite apparent to me are the difficulty of creating skintones, the possible heavy reliance on purples when it comes to shadow transitions, and the lack of greys.