Some shading techniques for tattoos include adjusting the pressure of the tattooing hand, diluting the ink with water or layering different colors. Consider the light source of a tattoo when shading with help from a tattoo artist in this free video on tattoos.
Okay, so when you're shading a tattoo basically what you're trying to achieve is a gradation in tone from dark to light. There's a couple of different ways you can do it. You can start off with a deep, with your darker tone. So, by adjusting your hand pressure that's one way to get the gradation in tone. The other method is to dilute your ink with a little bit of water so there's fewer particles in there. In other words, it's diluted. That's what's called a wash. So, depending upon the effect that you're going for using a wash might be appropriate for a piece that's only black and gray, or if you're going to be layering colors through it sometimes using just the straight black, and then by running color over atop of it you can get a variation in tone. Sometimes, if you're not absolutely clear because of the complexity of the piece how dark you need to go with your shading, you can come back at the very end with a little bit of black, so you just run mediums all the way through the, all the way through the piece, and then come back at the very end and just run your little pockets of black. Also, your shading and how it relates to your imaginary light source is important. You want to have your consis, you want to have your shading consistent through the entire piece, so want to have your imaginary objects, you want to have the shading, if it's top lit, on the underside of all the objects, or if you have a light source coming from the bottom side of everything then you do the opposite; show the bottom side of everything. Now, sometimes if you're working with a piece that has maybe multiple light sources then you might shade a little bit on the top and a little bit on the bottom. With a single single source lighting strategy sometimes you'd also want to run little drop shadows underneath underneath the, whatever the object is you that you've already shaded onto the surface of an adjoining object so that it looks like the piece is three dimensional. On this piece I'm using mostly just straight black, and then adjusting my hand pressure to get the effect, cause' I'm going to be running colors right back over the top of all this. And so, if I just make a dilution or a wash basically it's just going to get, it's going to get absorbed into it, and you won't see a range and tone in it, so that's why you use the straight black first just like this. Also, how your machine is running, and what your machine is designed to do makes a big difference. You want your shader to be running slightly faster than a regular coloring machine just so that your shading comes out smooth and doesn't look choppy. Also, you want your hand motion to be kind of light and circular, almost brushy, and build up the tones rather than just following in a solid field. So, on a piece that's entirely black and gray where you're using washes you'd basically dip your machine back and forth from your ink into your water until the the dilution in the cup had the consistency of the tone that you wanted, and then you just work solely out of that cup with the dilution in it; not not dipping any more for a while until you get to the very end after you've run all of your mediums. And then, sometimes using a a little bit of whiting for a highlight, or just having their skin be the highlight. And take your time with it too, and your if you try to rush it it'll it'll look rushed, and even though initially it might, you know, because of the irritation it's easy to get the illusion that you've got a smooth consistent range of tone, but after it's healed up you'll see that you were being fooled by the skin irritation, and not what's actually underneath the skin.