If you've never read Jonathan Gash's Lovejoy series, I recommend them to Bookhounds Keepers in particular. The TV series is fun too, but it has a broad comedy streak, and comedy rarely ages well. Still, it's worth looking at for the atmosphere alone, and since many of the episodes involve auctions of one form or another, it's handy for setting the scene if you have an auction coming up in your game and aren't sure what to do about it.
I want to talk a little about divvies, but for that to happen I need to describe Lovejoy to the uninitiated.
Lovejoy is the main character in the series. He's an antique dealer and forger with an unusual talent: he can spot the real thing. In the series it's described as a near-supernatural gift; he can just feel when an antique is right, a talent he calls his 'bell' which rings the minute he comes into contact with the real thing. It makes him especially desirable to a certain kind of collector, and also a certain kind of criminal. Often it means he's swept up in one scheme or another, desperately trying to keep one step ahead of the people trying to manipulate him.
The very first book, The Judas Pair, is a case in point; Lovejoy is hired to find a near-mythical set of flintlock dueling pistols, only to discover that murder follows in their wake, and not just because the pistols themselves are desirable. In that story Lovejoy is hired by the brother of a former owner, who apparently was shot with one of the dueling pistols, though neither weapon can be found. How did Eric Field die? Who has the pistols now? What are they prepared to do to keep them?
This is actually one of the better ones for Keepers to pick up. Since it is the first, Gash is heavy on the detail, and there's plenty here about the shadowy world of antique collecting and forging. However we're not here to talk about books: we're here to talk about forgery.
In the game, the Technical ability is described as follows: 'you can create a false document, forge handwriting with a sample to work from, or (given time) fake an entire book. This ability does not convey any special skill at creating aged paper or ink, or at bookbinding, or an ability to write or otherwise create a given volume.' Which is good so far as it goes, but the poor forger is then lumbered with half-a-dozen Art and Craft specialties that he absolutely has to have in order to do his job, and will never actually use in game unless the Keeper's feeling kind and manufactures a clue to suit his peculiar build. Given that ability pool points are at a premium during character creation, I tend to say that a forger needs Art and Craft, but doesn't need to sink points into all those different specialties.
However this merely means that the character can create a forgery, and I suspect in most games this ends up meaning that the players decide to make a small fortune by forging, say, the Cthaat Aquidingen half-a-dozen times, palming each hooky copy off on some unsuspecting occultist. How often does it happen that someone tries to pass a forgery off on the player characters?
The Document Analysis ability allows players to tell fakes from genuine, but there is no in-game equivalent for any other kind of Analysis. It could be easy enough to rationalize different kinds of Analysis, all of which are Technical abilities that do broadly the same thing as Document Analysis but which work in other mediums: Art Analysis, Weapons Analysis (for those antique arms and armor), Furniture Analysis, Collectables Analysis (for any small tchotchke that doesn't fit in the other categories), and so on. Naturally the characters aren't going to be interested in these Abilities, not unless toy collecting - or what-have-you - is also part of their store's remit. These would be NPC abilities, for those moments when your character has to phone a friend to properly identify and value the item in question.
Of course, this does tend to create the impression in the players' minds that Analysis (of whatever type) always works; you spend a point, you get the benefit. That isn't precisely so. I would count these kinds of Analysis in the same way the game counts Lockpicking: an ability that always reveals a clue when there is a clue to be had, but which can also be used as a General ability. General abilities can fail.
Which is where Lovejoy comes in. As a divvy he has a special talent, his Bell, which in game can best be represented by Idiosyncratic Magic, used to bump up a General roll that didn't quite hit the Difficulty target. Exactly how this would work is up to your enterprising Bookhounds, but I'm sure they can think of some peculiar ritual that helps them tell false from real.
In the Bookhounds universe, there's bound to be a few divvies out there with actual magical powers. There's also bound to be even more people who pretend to be divvies in order to get customers, or who actually believe they have powers when in fact they do not. The psychic field is full of deluded practitioners who honestly believe everything they say, but just because someone swears a thing is so does not make it so.
It's up to the Keeper whether he wants one of the player characters to be a divvie. There's no real harm in it, and it can help the forger out. I find that forgers in my games are a bit like netrunners used to be in Cyberpunk; the idea's great, but the actuality doesn't really work the way you think it would. Forgers often end up locked in the back room, talking to no-one, diligently creating fakes. They lack a reason to get involved with the outside world, but certifying true antiques from forgeries gives them a reason to get out and meet people, and having a reputation as a divvie means the outside world will eagerly come to them.
But what is a fake, exactly? It's something that pretends to be real, and have value. That 'have value' is the most important part of the equation; nobody bothers to forge things that are easily available on the open market, for little or no money. From a Bookhounds point of view, it's a potential disaster waiting to happen.
Consider: every shop, no matter what it sells, operates ultimately on the basis of goodwill. So long as people think the store is reputable and does good business, customers will keep walking in the door. Many businesses, particularly in the service industry, are bought and sold on the basis of goodwill alone, not its physical assets. Any restaurant can buy tables and chairs, but they can't buy customers, and if there's a food poisoning incident that hits the papers, you can bet that restaurant's goodwill just dropped through the floor. It's the same with a bookstore. Who wants to be known as the bungler that certified a fake as the real thing? What store wants a reputation for passing off hooky merchandise? That's why a reputable dealer, if he becomes aware of a fake in his collection, has to eat the cost rather than try to pass it on to an unsuspecting customer. The consequences of being found out are just too great.
From a game perspective, being found to have sold forgeries, knowingly or not, must count as a Reverse. That means someone needs to be checking incoming stock, to make sure none of them are too good to be true. I'd suggest a Difficulty 4 check once every so often, perhaps at the beginning of the session, though not at the beginning of every session. However I would suggest that successfully selling a valuable forgery does not count as a Windfall, except for shops with Credit Rating 1 or lower. One sale, more or less, does not make a business; but being caught selling fakes, even once, can ruin it.
That's it for the moment! I hope you found this useful.