This technique is not uniquely specific to pixel art, but it's a very common term to hear when starting out watching those "dos and don'ts" videos. So what is hue shifting?
Hue shifting basically means to change the hue when making your shade darker or lighter. In this context, 'hue' = colour!
You may hear 'you need to hue shift more' when getting feedback on your art, but what does that mean really? Here are some examples:
We can see even with just a bit of hue shifting, we have quite a different vibe for each drawing. In warm / daylight settings, no hue shifting can sometimes look a bit muddy or grey.
If we swap the image to grayscale, you can see that they look much the same:
As long as the hue shifted colours have a brightness that makes sense, they usually will work. You can get quite wacky with it.
But is hue shifting always good? Not necessarily.
Below is some of my art where I intentionally didn't hue-shift at all. You can see it gives them an uncanny, digital, or photographic kind of look. As always, techniques are about your intention, or personal style.
I recommend trying different hue shifting methods! I especially love to use a cool blue or teal for the lighter shades.
Thanks for reading and I hope this helped a little! Have fun with it!!