I'm a sucker for plastic pumpkins and acquire a couple every season in hopes that one day they will cover my lawn. These plastic gourds are classic decor, come in a variety of smiles and snarls, and they never rot and cause a stink. From a distance, they look fantastic as-is, but if you are using them indoors with regular lighting or in closer proximity, their plastic-ness becomes quite apparent (and maybe a little boring). However with a little paint and about 10 minutes I transform plastic jack-o-lanterns into color saturated monsters. (I prefer all my colors saturated in case you hadn't noticed.)
I use Liquitex Basics acrylic paints because they have a rich, opaque color and good consistency – not too thick, not too thin. The two shades I use are red oxide for the main ridges and burnt sienna for the crevices (to create a natural contrasting shadow). These shades tone down that super bright orange.
Using a few dry brushes, I cover one small section at a time with quick, broad, light strokes top to bottom in one direction. I'm not trying to cover evenly but rather let some of the bright orange peek through. Painting plastic is quite forgiving so if you add too much, you can easily wipe if off with a wet paper towel. I also tamp the brush on a palette to avoid getting too much paint on my brush.
Using a thinner brush, I then make a faint line with the darker paint and blend it in with gentle strokes. Dry brushing will result in visible stroke lines but I like the texture. You can allow the paint to set for a few moments then blot (not wipe) with a paper towel to soften the texture.
The final result is a much richer and textured pumpkin. The effect is not necessarily more "realistic" but the saturated color makes them a little unusual and creates certain depth. I also think they look a little more sinister, and after all that's the goal right?