Reenactor authenticity is a spectrum, not a line. Different groups and individuals aim for different levels, and the hobby accommodates all of them.
Quick answer. The three main authenticity levels in reenactment are progressive (hardcore, highest accuracy, every item documented), mainstream (good quality kit with some compromises for comfort and cost), and farb (casual, lower cost, less attention to detail). Most groups fall in the mainstream band. Progressive events are typically invite only and set higher standards. Farb is often a pejorative term used by progressives for less committed reenactors. Choose your level based on your interests, budget and the groups available locally.
Progressive (hardcore)
The progressive or hardcore approach aims for maximum historical accuracy. Every item of kit is documented from period sources (paintings, surviving examples, written descriptions). Every garment is hand sewn (or machine sewn only on seams that would have been machine sewn if machines had existed). Weapons are high quality reproductions or original pieces (where legal). Impressions are specific down to the regiment, rank and sometimes individual. Progressive events include high standards for the camp, personal items and behaviour. The approach is expensive but produces the most historically accurate experience.
Mainstream
Mainstream reenactment is where most groups fall. Kit is historically correct in silhouette and main materials, with some compromises for cost and comfort. Some items may be hand sewn, others machine sewn. Fabric is appropriate in weight and material but may be from modern mills. Weapons are good quality reproductions. Impressions are broadly historical but not necessarily specific to a single regiment or individual. Mainstream groups welcome new members and accept the realities of modern cost and time constraints.
Farb
Farb is a term coined in the American Civil War reenactor community in the 1960s, probably from Far Be it from Being accurate or similar. It refers to reenactors who make significant compromises on authenticity: polyester kit, modern eyeglasses on display, cell phones in camp, wristwatches, modern haircuts, synthetic fibres in the uniform. Not all farb is lazy; some is a cost compromise. The term is used negatively by progressive reenactors. Mainstream reenactors tolerate farb to varying degrees. The reality is that most reenactors have some farb in their kit, even if they prefer not to admit it.
Choosing your level
Most new reenactors start at the farb or lower mainstream end simply because they do not know what to buy. The usual trajectory is upward: as you learn more about the period and get to know your group, your kit improves. Some reenactors stay in the comfortable mainstream band for their entire career. Others push toward progressive, often requiring additional investment in better kit, hand sewn garments and specialist equipment. Both approaches are valid; the hobby accommodates both.
The social dynamics
Authenticity debates can get heated. Progressive reenactors sometimes criticise farb at mainstream events, which can be alienating for newcomers. Mainstream reenactors sometimes mock what they see as obsessive attention to tiny details. The best groups manage these tensions constructively, with authenticity standards clearly posted and newcomers given time to improve their kit. Avoid groups that are either dismissive of accuracy entirely (nobody will take you seriously) or hostile to newcomers who have not yet built a perfect kit (nobody can start perfect).
Public vs private events
Authenticity standards are usually higher at private events (training weekends, invitation only progressive events) than at public events (shows and festivals open to the public). The public is unlikely to notice whether your buttons are plastic or horn; the committed reenactor will. Many groups run private training events at the start of the season to improve kit before public events. This gradual improvement is one of the pleasures of the hobby.
Common questions
What is farb?
Reenactor slang for inauthentic kit or practices. Coined in the American Civil War community in the 1960s. Pejorative, usually.
What is progressive reenactment?
The hardcore approach aiming for maximum historical accuracy. Every item documented from period sources. Hand sewn garments where appropriate. Specialist and often invitation only events.
Do I have to be a progressive to enjoy reenactment?
No. Most reenactors are mainstream and enjoy the hobby fully.
How do I improve my kit over time?
Replace cheap items with better ones as budget allows. Attend training events to see how experienced reenactors wear their kit. Read period sources. Ask questions.
Are the authenticity debates serious?
Sometimes. In most groups, people respect different levels and avoid aggressive criticism. In a few groups, authenticity debates can become toxic. Choose your group accordingly.