In the parlance of historical reenacting, the word "farb" is a derogatory term for someone whose indifference to authenticity manifests itself in the use of inappropriate items or anachronistic comportment. The commitment to well documented items of period material culture and accurate historical impressions that draws many of us to the hobby can also produce extreme obsessiveness. There are some who would not dream of appearing in the field in anything less than hand woven, hand died fabrics and uncomfortable straight last shoes, and others who are content to use the best they can get until they can find something better.
Standards of authenticity can range from merely acceptable to absolutely hardcore, but "farby" gear and behavior can be glaringly off putting, and all things being equal I would rather avoid making common mistakes and ill advised purchases.
The trouble is that documentation for some of the items used during the time period of the American Revolution that I depict, either in general or by particular units, is often either extremely limited or non-existent. Unlike the mid 19th century, there are no contemporary photographs of items used and worn by the Continental Army, leaving us only with those artifacts that have survived to the present day, written records (often incomplete and inadequately described), and period illustrations and portraits which provide only a few glimpses of enlisted men and the way they lived, dressed and fought.
I fall in with the 1st New Jersey Continentals (2nd establishment), which depicts the unit on campaign as it was in 1777. This narrows the choices for uniforms and equipment in some respects - no French lottery coats yet - but even so there is no precise documentation of the cut and color of any locally procured uniform coats or any flag that may have been carried by the 1st at this time. Unlike some of its sister regiments in the New Jersey Brigade, surviving correspondence, deserter descriptions advertised in newspapers, orderly books and journals from the 1st NJ do not provide much in the way of definitive documentation.
It is possible that its commander, my ancestor Col. Matthias Ogden, was less attentive to the requirements of quartermaster and commissary than he appears to have been to grievances over the inadequacies of officer pay and to demonstrations of personal courage and daring in the field. It is also possible that in 1777, his first year as commander of the regiment and one in which the unit participated in almost constant marching and a number of sharp engagements, there was little time to devote to requisitions. Historian John Rees has done as fine a job as anyone of documenting the uniforms of the Jersey Troops in the early stages of the war up to the Monmouth Campaign in 1778, and this still leaves a good deal of room for informed guesswork and interpretation.
There is also the problem that even items for which there is contemporary documentation may be historically inaccurate when used by reenactors. Consider the "New Invented Haversack", a one strap knapsack offered for sale by modern sutlers and based on a February 1776 contractor's letter in the Maryland Archives which includes a detailed description of the item and claims that it had already been provided to PA, NJ and VA troops. One might think this was more than adequate documentation, but there is no surviving example of a knapsack of this type and no evidence that any such item was ever provided to troops in the field.
The general consensus among authenticity-conscious reenactors today is that this item should be avoided, but there are very few surviving artifacts or modern sources representing what would be considered an authentic knapsack. The best option I have found is a two strap linen canvas knapsack based on the one carried by Benjamin Warner of Connecticut and currently in the Fort Ticonderoga collection. I was able to get a Warner Knapsack kit that is no longer in production and am now learning how to sew it together authentically, but this takes a high level of commitment and is more effort than others in the hobby might consider worth taking. It ought to be easier to avoid farbiness than this.
The same charge of inauthenticity can be applied to the so-called "Pickering's Tool", an item designed and described by U.S. Quartermaster Thomas Pickering but for which no contemporary example survives in the archaeological record. Being made of iron, such tools may have been lost to corrosion, but still one would expect there to be some artifacts left if they had been widely produced. I learned this fact too late after purchasing my Pickering's Tool, but for $10 it was not as costly a mistake as it might have been and I will use it until I can replace it with something better.
Don't get me started on tents. There has been some excellent research undertaken by participants in the Yahoo group RevList that points to significant differences in authenticity between the 18th century tents manufactored for use during the Revolution and those available today from commercial manufacturers. The more authentic ones made by the 2nd VA are beautiful. Even so, unless you do it yourself, it is going to be extremely difficult to get a professionally made unbleached linen hemp duck canvas wedge tent (untreated) secured by wooden pegs through hemp rope loops with wooden washers and hand stitched grommets and with sectional tent poles held together with iron ferulles. The cost for such an item would be least twice what the standard cotton canvas wedge tent costs with flame retardant and water resistant coating. It will be vulnerable to mildew if packed when wet and may be a poor shelter during a downpour. Is it worth the effort and expense to go this route?
And that brings me back to subjectivity and the personal reasons we are drawn to this hobby. If you spend every waking moment critiquing the presentation of others in the hobby, you are just replicating a clique from High School (and a nerdy one at that). If you do not strive to learn from others in the hobby and to improve your impression, you are doing a disservice to the public and to your fellow reenactors. If it isn't enjoyable, there are better ways to spend one's discretionary income and leisure time.
On a scale of 1-10 where 1 is extremely farby and 10 is obsessively authentic, I am probably about an 8. I will shave my facial hair prior to the campaign season (and that, my friends, is a significant sacrifice to authenticity), but I will not worry if the interior, non visible stitching in my uniform coat is done by machine. I'll leave it to the really hardcore reenactors to go lose forty pounds and half their teeth and develop body lice if they want to. I am making careful choices, within my budget, in the items I acquire, and striving to improve my impression where it makes sense to do so.
Ultimately, what matters most is my behavior, on the firing line, in camp and in conversations with the public. It is more important to me to develop a greater appreciation for why people in the 18th century made the choices they did and took the actions they did - and to convey this to the public - than to quibble over minute differences in original vs. reproductions of the British long land pattern infantry musket. That distinction may be important to others, but not to the general public and is not my top priority.
Mind you, if you look in my haversack next month at Monmouth (a hand-stitched unbleached linen haversack, no less), you will find parched corn and a big slab of salt-cured bacon, nicely washed with the mold scrubbed off. My accouterments were chosen to be appropriate for early war Continental or militia use (hemp webbing instead of cotton or leather straps). My (used) civilian shoes have holes in them, and will be replaced with more authentic rough side out versions before the cold weather season. I have a wool blanket that is good enough for now.