Single needle tattooing is a variation of fine line and would be considered the finer of the two. On a technical standpoint, single needle is just that. One single tipped needle as the name implies. This allows an artist to produce razor thin lines for precise, detailed pieces ideal for highly intricate, monochromatic concepts.
Both fine line and single needle are great options when considering a delicate and or detailed tattoo. With that in mind, one technique isn’t always better than the other. More often than not, clients request single needle as their understanding is that single needle will achieve that light, dainty floral tattoo that they’ve always envisioned. However, lines can be too thin and using a single needle over a thicker liner can be counterproductive.
In short, all single needles are fine line but not all fine lines are single needle. That makes sense right? Regardless, when planning your next tattoo, be sure to do your research and consult with your artist. A reputable tattoo artist will provide feedback on what will produce the best results with your vision in mind.