photo editing - How are these washed-out, but bright, colors achieved?

I can't wrap my head around how the bright, washed-out colors in these images are achieved. Does anyone have an idea?

This Isn't Happiness: Closed for the Season, Salvador Cueva

Answer

They look to be done with a Hue/Saturation/Luminance tool, sometimes called a Hue/Saturation/Value tool. An HSL or HSV tool divides color into eight or so bands and allows you to adjust the hue, saturation, and luminance (brightness) of each color band separately from the other color bands.

In the case of your example, it seems the photos have been adjusted so that the saturation of alternating bands of color are moved in opposite directions. Red is boosted, orange is reduced, yellow is boosted, green is reduced (except the fourth image), aqua is boosted, blue is reduced, purple is reduced and magenta is boosted (particularly in the fifth one). The overall saturation is still held fairly low, but the absence of some colors makes the colors present look more vivid.

What is probably critical to make this work is that all general color casts must be removed. In addition to using the proper color temperature, white balance correction must also be spot on so that the whites in the scene are white.