Glossary
Original editorial content, made for people who want to understand before they buy.
Diameter / Gauge
The gauge indicates the diameter of each individual point. In needle codes it is expressed as a number: the most common values are 08 (about 0.25 mm), 10 (about 0.30 mm) and 12 (about 0.35 mm). The correspondence is an industry convention, not a standard.
Membrane
The membrane is the rubber or silicone element found in many cartridges that separates the needle from the part of the machine that moves it. It serves to limit the return of liquids towards the machine (backflow) and, according to manufacturers, can influence the needle's return and the give.
Needle Depth
Needle depth indicates how far the needle's tip protrudes from the cartridge's tip during work, and is linked to the depth at which the needle reaches the skin. In the industry it is also used to mean the protrusion adjustment on systems that allow it.
Needle Hang
Needle hang indicates the portion of needle that extends beyond the cartridge's tip, that is, the part visible outside the housing. It is often used as a synonym of needle depth, but some distinguish them: it is worth checking how the manufacturer defines it.
Grouping
Grouping describes how close together the points are within a group, for example a tight round liner or a looser one. There is no standard measure: it is described qualitatively by the manufacturer.
Pigmentation
Pigmentation indicates how much colouring matter an ink contains compared with the liquid that carries it. It is not a standard value reported uniformly: manufacturers describe it in words or through colour rendering.
Viscosity
Viscosity describes how fluid or thick an ink is, that is, how easily it flows. It depends on the formulation and can change with temperature. In product sheets it usually appears as a description («fluid», «thick») rather than as a measured value.
Opacity
Opacity indicates an ink's ability to cover what lies beneath without letting it show through. It is a concept tied to the colour's appearance, not a standardised measure, and manufacturers describe it in different ways.
Saturation
Saturation describes the intensity and purity of a colour: a highly saturated colour looks vivid, a less saturated one looks more muted or greyish. It is a colour-theory concept and does not indicate how much pigment the ink contains.
Mixing
Mixing is the blending of inks, or the dilution of an ink, to obtain a shade or gradation different from the original. Some manufacturers provide guidance on compatibility between their own products.
Grey Wash
Grey wash is a series of grey gradations obtained by diluting black with a compatible liquid, or a set of ready-made greys in different intensities. The dilution ratio and the products to use are indicated by the manufacturer.
Blackwork
Blackwork is a style that uses black as its main element, with solid lines and surfaces, often without colour gradients. In product language the term also indicates black inks described as suited to this type of work.