I've been trying to do this project and every time, with this specific project, this happens. I don't know if it's an issue with the "expand" command, because it doesn't happen with regular marquees. I can always just erase the excess and use a brush to go over the light areas until they're at their darkest, but I figured there's an easier way to do this?
So pretty much I select my image, delete the white around it. Then I expand what I have selected by 50 pixels so it surrounds my image. Then, on a separate layer, I fill the expanded marquee selection with white.
But as you can see, the color leaves small, light blotches outside of the marquee area, as seen by the feet, and part of the area within the marquee is also very light, as seen by the shoulder area. How do I solve this issue?
You have some semi-transparent pixels floating out in those areas. You might not see them because they could just have as little as 1% opacity instead of 100% like the rest of your illustration. A good trick to find those pesky pixels is to go to the bottom of the layers panel and click the "fx" buttons. Add a stroke to your layer with some kind of colour that stands out. The stroke will be applied to the edges of opaque pixels and even bleed into the faintest pixels. Just grab your eraser and brush those revealed spots away and then trash the stroke effect.