Turn any photo into a dot grid artwork with these Photoshop actions. You'll get great results with dots that change size. They get larger in brighter areas and smaller in darker areas. Free download available.
Learn how to use luminosity masking in Photoshop. Luminosity masking lets you make a layer visible according to the brightness value of your photo. For example, you can brighten your photo and then apply luminosity masking so that it doesn’t overexpose the areas that are already bright to begin with. You can also apply color grading effects to different tonal areas. You can do HDR tone mapping with it… and a lot more.