On a tattoo machine, L stands for Liner and S stands for Shader. These labels tell you what the machine is built (or configured) to do: a liner machine drives needles quickly for crisp lines, while a shader machine runs slower and softer for filling in color and gradients. The two machines differ in their internal components, speed, needle stroke, and voltage settings.
What a Liner Machine Does
A liner machine is designed for single-pass, sharp lines. It moves the needle in and out of the skin quickly, depositing ink in a thin, precise track. This fast cycle is what gives tattoo outlines their clean, defined edges. Liner machines are paired with round liner (RL) needle groupings, where a small number of needles are soldered together in a tight circular formation. A common setup might be a 3RL or 5RL, meaning three or five needles bundled tightly together for fine to medium line work.
Because liners need speed, they’re built lighter and tuned to hit harder and faster. On a coil machine, that means fewer wraps of copper wire around the electromagnetic coils, typically 8 or 10 wraps, and a smaller capacitor in the 10 to 22 microfarad range. The smaller capacitor charges and discharges quickly, keeping the needle cycle rapid. On a rotary or pen-style machine, lining is done with a longer stroke length of 3.5 mm or above, which gives the needle enough travel to punch ink cleanly in a single pass.
What a Shader Machine Does
A shader machine runs slower and with a softer hit. Instead of punching a single line, it’s built to layer ink gradually across a broader area, creating smooth gradients, soft shadows, and solid fills. Shader machines use round shader (RS) needle groupings, where the needles are arranged in a looser circular pattern than liners, or flat and magnum configurations that cover more skin per pass.
Coil-based shaders typically have 10 or 12 wraps of wire on their coils and a larger capacitor, usually 22 to 47 microfarads. The bigger capacitor takes longer to charge, which slows the needle cycle and produces a gentler, more controlled stroke. On rotary machines, shading works best with a shorter stroke length of 1.8 to 2.5 mm for soft black-and-grey work, or a medium stroke of 3.0 to 3.5 mm for blending. The shorter travel keeps the needle from hitting too hard, which prevents overworking the skin during multiple passes.
Voltage Differences Between L and S
Liner and shader machines also run at different voltages. A liner needs quick needle movement, so it typically runs at a lower voltage: around 7 to 9 volts on a rotary machine, or 6.5 to 8 volts on a coil machine. A shader needs smooth, controlled hits for layering tones and generally runs slightly higher: 7.5 to 9.5 volts on a rotary, or 8 to 10 volts on a coil.
Color packing, which is a more aggressive form of shading where you saturate an area with dense pigment, pushes even higher at 8.5 to 11 volts on a rotary. These ranges are starting points. Skin type, needle size, and ink consistency all influence the sweet spot, and most artists adjust by feel once they start working.
How Needle Codes Connect to L and S
You’ll also see L and S in tattoo needle codes, and they correspond directly to the machine labels. A needle labeled “08RL” means eight #12-gauge needles grouped in a tight round formation for lining. A needle labeled “08RS” means eight needles in a loose round formation for shading. The number tells you how many needles are in the grouping, and the letters tell you the arrangement and intended use.
Round liners (RL) are the standard pairing for an L machine. Their tight grouping concentrates ink into a narrow point. Round shaders (RS) pair with an S machine. Their looser spacing spreads ink across a wider area with each pass. Beyond these, shader machines also work with flat (F) needle groupings, where needles sit in a straight row, and magnum configurations designed for covering large areas efficiently.
Why Artists Use Separate Machines
Most tattoo artists keep at least two machines set up during a session: one configured for lining and one for shading. Switching between a liner and shader mid-tattoo would mean changing not just the needle but potentially the voltage, the contact screw gap (on coil machines), or the stroke setting (on rotary machines). Having dedicated machines eliminates that downtime and keeps each tool optimized for its job.
Some machines, particularly modern rotary pens, are adjustable enough to handle both tasks by swapping the stroke cam or adjusting the give setting. A 12-wrap coil machine can also serve as an all-around machine capable of both lining and shading, though most professionals still prefer purpose-built setups. If your machine came with two units labeled L and S, the manufacturer has already tuned each one for its role, so use them accordingly.