Gutiérrez Solana painted The Asphalt Layers of the Puerta del Sol (1930) at a highly important moment in his career, following the 1929 retrospective exhibition at the Museum of Modern Art in Madrid. It came as the culmination of his most fertile period in the 1920s. The painting depicts a group of workers, emphasising their physical effort, stark humanity and vigour. These are all typical motifs from the artist's repertoire, but here he treats them in a way that is part-caricature, part emaciated portrait. In consequence, what might initially appear to be a documentary scene of city life is more akin to the artist's famous carnival masks. This is particularly obvious in the one face that is depicted head-on in the scene. Gutiérrez Solana's tendency to paint characters in circular compositions in seen by some scholars as reflecting the clear influence of Goya. Other examples include The Émigré's Return (1924, Banco Santander Collection), The Gathering at the Café de Pombo (1920) and Cádiz Street Musicians (circa 1938), both in the Museo Reina Sofía, In The Asphalt Layers of the Puerta del Sol, the characters are shown grouped around a large drum in which the asphalt is being melted. According to Manuela Mena, this picture may have been inspired by Goya's The Forge (1815-1820, Frick Collection, New York). This would place it among the artist's occasional literal citations of Goya, especially in his compositions and human types, applied here to a costumbrista motif. By depicting this nocturnal urban activity, Solana was able to being a sense of tenebrism to the scene, with the sombre faces veiled in smoke.

Some writers have seen a direct antecedent in the etching of the same name engraved in 1900 by Ricardo Baroja, brother of the writer Pío Baroja, a copy of which is preserved in Spain's National Library.

However, if this work did indeed have any influence on Gutierrez Solana's painting, it was limited to the choice of subject matter. The Asphalt Layers of the Puerta del Sol was painted several years before his series of paintings of different trades, such as Skinners (circa 1939, private collection). It thus represents an early example of Solana's pleiad of fishermen, butchers and other industrious male characters, which, taken together, constitute a crude and fatalistically represented fresco of the working classes against the backdrop of the metropolis. However, in this group of men mechanically stirring the hot liquid with their shovels in the half-light, we see not only Solana's socialising and pessimistic discourse, but also his fondness for mannequins, articulated dolls and automatons, which Eugenio Carmona refers to with the Freudian term 'uncanny' (Unheimliche).

This version of The Asphalt Layers was shown at the Spanish Pavilion in the Sixteenth Venice Biennale in 1930 under the title Lastricatori, as well as in other exhibitions in Spain and abroad. The frequency with which the painting has been shown elsewhere has led a number of scholars to confuse it with another version, now at the Nagasaki Prefectural Art Museum, which is almost identical in its composition. That smaller canvas (measuring 100 x 73 cm), was the first item in an extraordinary set of Spanish art collected by the Japanese Minister Plenipotentiary in Madrid, Yakichiro Suma, who acquired it on his arrival in Spain in 1941, just hours before presenting his credentials to Minister Serrano Suñer. In those years, the larger work belonged to a private collection in Barcelona, from where it was transferred to the Banco de España Collection in 1998.

Carlos Martín