Two numbers describe a tattoo needle before you get to how the needles are grouped: the gauge, which is the diameter of each needle, and the taper, which is how long the point is ground. Both change how ink enters the skin, and both are the rows a spec sheet most often leaves vague.
Gauge
| Gauge code | Diameter | Common name | Generally used for |
|---|---|---|---|
| #08 | 0.25 mm | Bugpin | Very fine lines, tight detail, some realism work |
| #10 | 0.30 mm | Standard bugpin / fine | Fine lines, smooth shading |
| #12 | 0.35 mm | Standard | Bold lines, colour packing, most everyday work |
A thinner needle carries less ink per pass and makes a finer mark; a thicker one carries more and works faster on larger areas. The first two digits of a cartridge code are the gauge: 1003RL is three #10 needles, 1207RL is seven #12. The same count in a different gauge is a different tool, which is why a stock list should name both.
Taper
Taper is the length of the ground point. A longer taper is a finer point that enters the skin with less resistance and tends to deliver ink more gradually; a shorter taper is a blunter point that deposits ink faster. Artists describe the difference in terms of control versus saturation, and which they prefer depends on the style and the machine. Taper is measured in millimetres. When a sheet says "long taper" and gives no length, it has told you nothing you can compare.
What a sheet should state
- Gauge as a code and a diameter (#12 · 0.35 mm), not one without the other.
- Taper as a length in millimetres, or an honest "not yet confirmed".
- Needle count and configuration, so the code can be checked against the box.
- Sterile, single-use, and the pack size.
On our cartridge sheets the gauge and configuration are stated on every box; taper reads confirmed on arrival of first lot until we have measured it on a box we received and can write the number down. We would rather show an empty row than a guess.
Choosing a stock
Most studios settle on one gauge for lining and one or two for shading, and keep the counts they use every week in depth. A box of twenty is a lot; the lot number on it is what lets a box be traced if anything is ever wrong with it, so the box stays until the last cartridge is gone.