A common concern for buyers of fine art is whether what you pay for the work of art you have come to desire is fair and not overrated. Even after establishing the authenticity of a piece and assuming its provenance is impeccable, it is always possible that there is something your untrained eye cannot see that affects the value of the work.  

Previous restorations of damages, in-painting and even hidden signatures can be very well concealed and greatly diminish the value of a work. It is therefore imperative before you commit your money to a piece of art, to subject it to an inspection under an ultraviolet (UV) lamp.

In a darkened room, UV light reveals alterations such as over-painting, repairs and floating signatures on artwork that is normally not visible in daylight. Even the slightest alteration will stand out with clarity under UV light.

If you know what to watch out for, UV light inspection can be used for oil paintings, porcelain, glass, ceramics, paper art, textiles, marble, jade, ivory and clocks.

Here's an example of previous restoration on a painting that is not visible to the naked eye: 

So, buyers: before you venture out to invest in that work of art that clicked with you, make sure you get what you pay for. 

Sellers of fine art: this is crucial for you as well. You must insist that the work of art you are selling is subjected to UV light inspection. This will safeguard you against any future complications with post-sale restorations. Having proof with regards to the condition of your art at the time of sale can potentially save you a lot of unnecessary, and possibly costly, future trouble.