I've been looking at art from an online game called Maplestory and I've noticed that much of the art as well as the in game backgrounds, characters, etc., have this really nice grainy effect and I've been trying to achieve it (using photoshop) but I can't get it to look the same. I've tried using the noise effect but it's not the same. The effect looks more like a dithering effect that pixel artists do, but I'm assuming the artists for these drawings do not place individual pixels, considering the resolution of the drawings, but I don't understand how they are able to achieve this effect.
Notice how this looks much cleaner than just the noise effect. Also, some areas seem to be grainier than others, which makes me feel like this isn't just some sort of effect they're throwing over it.
Also notice how it looks like the shading was done with this effect. A good place to zoom in on is the grass or the trees