When people talk about a bright mix they are referring to the colors of the different sounds they hear. You want to think of the color palet of the mix you are creating like a mood board, think about what sounds mesh together, you want a balance between these sounds and you want to make sure the sounds aren't clashing with one another while still taking their space in the mix.

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Creating a Colorful Mix:

Though some of this coloration can be done in post with effects such as saturation, chorus, flanger, reverb, and delay, a lot of the color is gonna be done with the sound selection and sound design of the source. One of my favorite and most colorful records that incorporates color into its sound wonderfully is Stevie Wonder's songs in the key of life. Every song on here is packed full of interesting and dynamic tambres that brings each track to life. to me when I hear these tracks my brain automatically thinks I'm hearing green. Its got to be those rhode keyboards and those little percussive hits.

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Examples of very bright mixes in modern music:

Somebody that comes to mind as having exceptionally bright mix is the Weeknd's blinding lights. If you listen you can clearly hear how much top end crispness is in this mix. It makes it sound incredibly clean and polished and definitely achieves what a pop mix is supposed to in the modern era.

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Bright mixes done with fewer resources

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As great as the Weeknd's blinding lights is, it was also made by professionals with massive budgets. If you are anything like 90% of artists today you don't have that. An amazing bedroom producer who has revolutionized bedroom pop is Pink Pantheress and her mixes are incredibly colorful and bright without being obnoxious and she producers all her own stuff. Her sound selection is incredibly unique, bright, and poppy but its not annoyingly bright.

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