Love the details. Though I was wondering if it was an artistic decision to make the colours have a washed-out/desaturated appearance?
Without going into too much colour theory, I might recommend laying off the white and black values. Contrary to what might seem intuitive, adding white and black does not necessarily create brighter or darker colours but instead reduces the saturation. This can result in your colour palette becoming washed out and give a milky, faded look.
On colours, highlights and shadows: - It's not wrong to add black to shadows, however shadows are seldom solely black and adding too much black can dull your image and drain it of vividness(if this is the look you are going for though, it can be done better by preferentially using 'cool' colours on the colour wheel). To create a contrast and the illusion of dark and light, you must come to grasp with what are commonly referred to as 'cool' and 'warm' colours on the colour wheel.
Above you can see several depictions of colour wheels divided between 'cool' and 'warm' colours. By separating highlights and shades between the two sections, we are able to create contrast
without desaturating our colours. Depending on how you want the image to feel you can play around with what you want to be warm and cool. Usually the colour temperature of the light source determines the colour temperature of the shadows,
e.g. cool light, warm shadows and vice versa.Furthermore, I want to politely comment on the addition of white. In real life, white light does not change the
saturation levels of the colour that it is hitting because of this, it is not necessary to add white in order to create a sense of brightness(though I could be wrong). To get something that really pops try to use as little white and black as possible, it should be no more than ten percent of the image. If you are looking to create a scene that looks moody, dark or realistic, you may be better off using either lots of cool browns or cool blues/purples/reds.
White and black are good tools but are traps, and great adversaries to be tamed and used with vigilence, they can really make or break a colour palette!Otherwise, fantastic work!
—Stux