A rare collection of historic grand pianos emits the authentic but forgotten sounds that transport the audience at a celebrated new music competition in Poland back to the times of Frederic Chopin. Unlike their modern, glossy black, lacquered heirs, the instruments dating from the 19th century also boast rich brown hues of varnished wood. The makes and models include some of the favourites of the prolific 19th-century Polish-French pianist and romantic composer, who died in France aged 39 in 1849. Now 30 pianists from around the globe, taking part in Poland's first International Chopin Competition on Period Instruments, can pick and choose from among the pianos. "They all date back to the 19th century and Chopin played on each of these models," Artur Szklener, director of the Warsaw-based Fryderyk Chopin Institute told AFP, referring to five grand pianos gracing the stage of the Warsaw Philharmonic among the special collection. "His favourite was the Pleyel, but we also have Erard, Buchholtz and other period pianos," he added, saying that they were borrowed from various collections, including his institute. Unlike today's standardised grand pianos, models created during a period of technical innovation during the 19th century vary widely in their construction and quality of sound, giving each instrument its own individual personality. Depending on the model, the brand and year of manufacture, "it feels like you're listening to a lot of different sounds, lots of different pianos," said Claire Chevallier, a specialist in antique pianos and a jury member at the competition in Warsaw. - 'Extremely demanding' - Chevallier said she wanted competitors to "be at one with what each instrument can offer" so they can express "very personal things, very adapted to the instrument and its quality of sound. "At the same time, there should be a little bit of novelty in the music of Chopin that is heard so often," she told AFP, as the competition got under way. The use of the historic pianos makes the event that runs from September 2-14 with a first prize of 15,000 euros ($17,400) unlike any other in the world, according to the Chopin Institute. The competition is modelled on the venerable International Chopin Piano Competition, launched in Poland in 1927 and held every five years since 1955. Winning the prestigious event opens doors to international careers. But winning a competition with period pianos poses perhaps an even greater challenge to musicians accustomed to standardised modern instruments. "These instruments are extremely demanding at the technical level, the level of listening and the level of managing the acoustics of the instrument, not to mention the acoustics of the room," according to Chevallier. "They are unforgiving. For example, they have very uneven musical scales, while on a modern piano the transition between scales goes totally unnoticed," she said, referring to octaval changes being much less fluid on antique pianos for technical reasons. - 'Organic' - Like his competitors, French pianist Benjamin d'Anfray, 30, is well aware of this. "Every era has its own style of piano and its own technique, so we can't play these instruments in the same way that we play a large concert Steinway. "We can't be heavy-handed, we can't use the pedal in the same way, we focus more on the keyboard," he told AFP, after his first recitals on the Buchholtz and Pleyel models most favoured by Chopin. "The Pleyels have exceptional singing qualities, that we've lost in our modern pianos. "When we play them we can be sucked into another world, we can have sound sensations and worlds of sound that are completely different," d'Anfray said. Finding these revered pianos is by no means a simple task. "Very old pianos in good condition are very rare but when you find one, it's paradise," d'Anfray remarked, pleased that there are 20 period pianos available for the pianists to explore at the competition both on stage and in rehearsal rooms. According to Chevallier, there is also an ecological and social note to the event. "It's really organic, I mean we're recycling existing instruments and that could create an extraordinary market and a lot of work for many restorers and tuners."