There are several ways to do this. If you wish to work destructively (in other words, permanently changing pixels), use a Levels adjustment and bring the leftmost and rightmost triangles close to each other near the middle. That'll make all dark colors black, and all light colors white. If there're random light pixels left in the middle, you can paint them with a black brush. My preferred method is to select the part you want to be solid black. If your image is close to a silhouette already, then I'd use the Select Menu>Color Range option (click a black, and then, holding shift, drag over all the areas you want selected. When you hit okay, you'll have a selection in the shape of the silhouette. Then, click the New Layer Icon (foldy piece of paper on the bottom of the Layer Panel, and go to Edit>fill to fill your selection with any of the choices in the dialog box drop down menu. This'll put the pixels on their own layer, making them easily changeable. If you end up seeing some of the edges of your original (bottom) layer, you can always add a new layer, drag it between the silhouette and background, and fill that with a different color. If you REALLY want to work in a more experienced manner, once you have the selection, instead of making a new layer by hand, make a solid color adjustment layer (you'll find that option in the black/white circle at the bottom of the Layer panel). It'll use your marching ants to make a mask on a solid color layer. Then, you can double click the non-mask part of the layer to change the colors to your heart's content! In my video below - I worked partly destructively. My image was light, so I used Levels to make the apple part darker (on the original layer, since I wasn't going to need it again). Levels needed to be adjusted further right, because of the need for more darkness. I finished off the selection with the Quick Select tool.
... View more
AdChoices