If the Chiaroscuro Quartet experienced any nerves at their Edinburgh International Festival debut at the Queen’s Hall, complete with full house and BBC Radio 3 recording team in place, it certainly didn’t show. Formed in 2005, this young, period instrument quartet, appeared completely at ease and at one with the music. I had read that the four members (Alina Ibragimova, Pablo Hernán Benedí, Emilie Hörnlund and Claire Thirion) prioritise quartet rehearsal over many rival opportunities and the rewards of such dedication certainly came over in the performance. Their excellent ensemble skills rely much less on eye contact than is often the case in quartet playing. It seemed to be much more about listening and “feeling” the music together.

The light, clear sound of their gut strings complemented the bright textures of their opening piece, Mozart’s 1773 String Quartet in F major, K168, written when the composer was only seventeen. Attention to dynamics and articulation were very impressive from the outset.

The quartet couldn’t have chosen a better opener to highlight their titular light and shade, as the con sordino (muted) second movement moves straight into the key of F minor. The contrapuntal material is also darkly angular, its theme not unlike that of Handel’s aria “And With His Stripes We Are Healed” from the Messiah. Mozart’s four-bar theme features tied notes across the central barline, lending a searching, uncertain air to proceedings. This beautifully played movement over, light reappeared unmistakably in the brisk, unmuted Menuetto which returned to F major. In the overlapping conversation of a fugue, one way to ensure that each entry is noticed is if its beginning differs from surrounding material. Each phrase of this cheery, confident, closing fugue begins on a minim while all around play quavers and, more often, semiquavers. I really enjoyed this breezy opener, the only piece on the programme which the quartet have not recorded.

A decade is a long time in a short life and, in the years between the composition of the piece just played and the one to follow, Mozart had met Haydn, played quartets with him, and studied his senior colleague’s Op. 33 quartets. The effects of all of the above could be heard in Mozart’s 1783 String Quartet in E flat major, K428. Little knowledge of musical notation would be required to identify a more democratic distribution of interest across the parts in the later work. I found this particularly resonant, as the Chiaroscuro Quartet strike me as a model of democracy in chamber music. Anyone unaware of the tradition of leadership falling to the first violin would not readily have guessed it from the collegiate body language of the members. The way the members moved was also very interesting. At one point all three standing members took a simultaneous step back, as if to make room for a forte chord. In other moments they seemed unconsciously to sway in sympathy with one another and with the music. I was especially impressed with the ensemble in the closing Allegro vivace whose opening bars are peppered with synchrony-challenging rests. Dynamics were also effectively observed here, particularly in the quartet’s change from forte to piano over a three-note figure in the movement’s second theme.

Following a sunny interval, the quartet resumed with Schubert’s 1824 String Quartet in A minor, D.804, “Rosamunde”. The subtitle refers to Schubert’s music for Helmina von Chézy’s unsuccessful play of the previous year, Rosamunde, Fürstin von Zypren (“Rosamunde, Princess of Cypus”), a wistfully lyrical theme from which features in the second movement. Another darker self-borrowing employs a melody previously set to Goethe’s Gretchen am Spinnrade (“Gretchen at the Spinning-Wheel”). This music, which opens the first movement, hints at Schubert in mortality’s early embrace. The song features the line: “My peace is gone, my heart is heavy; I shall never find peace again”. I felt that the quartet tapped very affectively here into the tristesse at the work’s heart; a shift to the major brings little in the way of convincing or lasting cheer and there was great tenderness in the playing.

That said, there was tremendous lightness in the closing, musette-like Allegro moderato – possibly my favourite moment of the morning. In addition to fine articulation, what impressed me particularly was the effortless passing of sextuplet semiquavers from Emilie Hörnlund’s viola to Alina Ibragimova’s first violin. This was unfussily executed and all the more pleasing for that.

With so many other strings to their bows and styles at their command, it is to be hoped that the resolve of these fine young players to dedicate so much of themselves to chamber music remains in place.