Classic cars are in vogue. Well-preserved, classic vehicles are considered collector's items, but are valued as an investment. Legendary racing and sports cars from Ferrari, Bugatti or Porsche as well as individual collector's items can be worth several million euros. The following applies: models that are in particularly good condition which have only undergone few repairs or restorations are particularly valuable. However, due to the fact, that they are often used as sports cars, these are extremely rare. The most expensive car ever sold at auction is a 300 SLR Uhlenhaut coupé - a Mercedes sports coupé from 1955 - for 135 million euros at an auction in 2022.

Accordingly, it is immensely important for collectors such as museums or private owners that the classic car really is an original and not a fake. Special valuations and certifications assess the originality of classic vehicles and thus offer security for owners, buyers and insurance companies. Forensic methods, which are otherwise better known from crime thrillers or forensic medicine, are also used to check authenticity.

When buying a classic car, several factors play a role in the long-term value retention. These include the condition of the vehicle and a complete and seamless history. Ideally, the vehicle should be well-maintained and in good condition with comprehensive documentation of repairs and restorations carried out. The rarity and demand for the model also play a major role. Furthermore, if a classic car has a special historical significance or was used as a special film requisite (such as James Bond's elegant Aston Martin in "Goldfinger"), this can also increase its value. The 300 SLR Uhlenhaut coupé combines all of these aspects: there are only two prototypes of this model in the world, it has been very well maintained, its history is clearly documented and among insiders it is known as a legendary design for endurance racing.

If there is suspicion of a counterfeit or if there is uncertainty about the origin of the vehicle, a valuation provides security. Experts use various methods to check the authenticity of cars. First, the history is examined using existing documents and cross-research in literature, associations and the Internet:

• Where does the vehicle come from?
• Where was the chassis number recorded?
• When and where was the car registered or used?
• Has the car ever been sold?
• What did the vehicle look like in the past?

Forensic methods are also used to check authenticity to expose possible deception. In addition to examining the design, the original parts or the chassis number, technical methods such as magneto-optical processes (to uncover manipulation of inserted numbers such as the chassis number, for example), paint layer thickness measurement, ultrasound and material analysis using optical emission spectrometry help to check whether the vehicle actually has an original identity.

The precise analysis of the steel and other metals used can clarify whether a classic car is authentic. What type of steel was used in the body and does it correspond to the original condition? The frame and chassis, for example, can provide information about the age based on the alloy and the degree of hardness.

Mainly the trace and accompanying elements that indicate certain eras of steel production are considered. Old steels are generally less pure than more recent steels. In particular, a high carbon content and a high content of phosphorus and sulfur are indicators of older material.

Optical emission spectrometry (OES) with spark excitation is considered the most reliable and established analysis technique for determining the material composition - the elements of which the metal is composed in percentages. The results can be used to determine the age of the material to within a decade at best, based on the elements and the manufacturing process.