The art market is estimated to be worth over $45 billion and many analysts believe that at least half of the artwork circulated within it is fake. The more successful an artist becomes, the more likely their work is to be counterfeited.

Thankfully, authenticators have identified tell-tale clues that can help you identify a forgery. Below we've broken down five ways to spot fake work from Keith Haring, KAWS, Banksy, and Warhol, just in case you wanted to start building your own legit collection or, you know, just show off a bit.

Haring

1. If the signature is big, think twice

Authenticator Richard Polsky identifies that Haring always signed his work but was sure to make sure it didn't draw attention from the subject of the piece. If the first thing you notice is the signature, chances are it's not it.

2. Look for asymmetry and tearing on the edges of his “Subway Drawings"

Polsky also notes that between 1980 to 1985, Haring produced up to 3,000 “Subway Drawings." A genuine example would have had to have been torn from the walls of the New York subway so look for raggedy edges and remnants from other posters.

3. Check "K"s and "H"s

When signing his works, Haring Haring would write the vertical lines of both of these letters with a swoosh. Erling Løken Andersen suggests that he would start line at the top, then let it “slide” to the left, before right again, making the line assume a very faint inverted “S”-shape. This feature is a good way to authentic Haring signatures.

4. Check the numbering  If you’re dealing with a Keith Haring print, it should be numbered and you can actually  check the edition size of most Haring prints on Haring.com.

5. Look for unbroken lines

Polsky reveals that counterfeiters struggle to replicate Haring's incredible draftsmanship. A hesitant line that isn't continuous is a good indicator of a fake.

KAWS

1. Check the font on the packaging

This is where forgers tend to slack. Fake companies will often miss-size or exclude elements of the font and text.

2. The color gives it away

Genuine KAWS will always use true colors while knockoffs will use cheap dyes. See here for comparison.

3. The eyes never lie

One of the quickest ways to spot a fake is in the eyes. If the crosses are too even and don't reduce to a point, it's probably counterfeit.

4. Check the density

Authentic KAWS companions shouldn't feel hollow.

5. Cross-reference

It always pays to cross-reference the piece with KAWS's official releases.

Banksy

1. Busy location meets a political subject

While other graffiti artists go for railway lines and areas with low foot-traffic, Banksy aims for the wider public by targeting busy locations.

2. Ask a local

Banksy reportedly asks for permission before executing a mural on a residential property so it's worth checking with the owner.

3. Look for detail

Impersonators are usually in a rush and will only use one stencil so the works lack detail. Banksy, on the other hand, uses multi-layered stencils.

4. Pay attention to the signature

The signature should be a blocky, stenciled "Banksy." The only trouble is, after a while, he stopped signing them.

5. Check with Pest Control

They're the office that handles the paperwork for Banksy. They keep detailed records of all the artwork, answer inquiries, and are the sole point of contact for the artist.

Warhol

1. Look for inconsistencies

Warhol would vary the amount of ink he squeegeed through the silkscreen, creating idiosyncracies that forgers can't duplicate. Warhol expert Richard Polsky notes, "Sometimes, Warhol used too much ink, resulting in a dark impression with less detail. On other occasions, he used too little ink, which created phantom-like forms."

2. Check the signature

As Warhol’s art evolved over the years, so did his signature. Depending on the era, Warhol’s signature varied from cursive and print to initials and stamps. Check if the signature style corresponds to the right era here.

3. Look for fading

If it's in mint condition, something is fishy. Warhol’s classic prints series (the “Flowers,” “Campbell’s Soup Cans,” and “Electric Chairs”) are often faded. Print shops have tried to revive them by rescreening them but Polsky suggests that "this misguided attempt at “refreshing” the image essentially makes it no longer an original—and instead renders it virtually worthless."

4. Size Matters 

A 40” x 40” Liz Taylor print dated  1970 is probably a forgery because Warhol created his Taylor prints much earlier and didn't experiment with screenprinting on large scale mediums until later. It pays to cross-reference the date on the work with the kind of work he was making at the time.

5. Avoid Mickey Mouse drawing in Sharpie

In his pre-Pop period, Warhol sketched Mickey Mouse drawings with graphite, on high-quality paper, utilizing his “overhead projector” tracing technique.Polsky reveals forgers will try to replicate the series with Sharpies on cloth napkins and handkerchiefs, that's a red flag.