Pix or pitch made from the resin of various coniferous trees was in common use since antiquity, and variants of this substance, often named after their place of origin, were described by Roman writers such as Pliny, Columella, and Dioscorides.
Antonius Musa Brassavola, Examen omnium simplicium medicamentorum, quorum in officinis usus est (Lyon, 1537),
p. 377 explains with regard to pix Hispana:
Hinc est quod pix Hispana varios colores habet: quandoque, fuluum et aureus, si ex laricis resina fiat, quandoque albicans, si ex pini vel picea fiat. [...] Hispana nuncupatur, quoniam ex Galliae & Hispaniae montibus ad nos magna copia comportatur, quamuis & in Intalia sit plurima: eadem ratione & Graeca dicitur, quia ex Graeca affertur: & Colophonia, quoniam Colophone invehebatur
My translation: "Hence it is that the Spanish pitch has various colors: sometimes yellow and golden, when it is made from larch resin, and sometimes whitish, when it is made from pine or spruce. [...] It is called Spanish, because a great quantity is brought to us from the mountains of Gaul and Spain although there is also much from Italy. For the same reason it is also called Greek, because it is brought from Greece. Also colophony, because it is acquired in Colophon."
In antiquity colophony (rosin) was shipped from the Greek city of Κολοφών. The various kinds of pitch differed in their characteristics, based on which kind of tree was used as the source of unprocessed resin and differences in the process of extraction and refining.
Gaius Plinius Secundus, Naturalis Historia (XIV,127) informs us:
Pix in Italia ad vasa vino condendo maxime probatur Bruttia. fit e piceae resina, in Hispania autem e pinastris minime laudata. est enim resina earum amara et arida et gravi odore.
My translation: "The pitch that in Italy is most highly esteemed for vessels for packing wine is the Bruttian. It is made from spruce resin, the one from Spain is from pine and not esteemed much. It is namely this resin bitter and dry and of strong odor."
In antiquity, Bruttium was the region at the toe of Italy, occupying roughly the area of modern-day Calabria. According to the Oxford Latin Dictionary, picea is most likely a spruce of the species Picea abies, while pinaster is identified as the maritime pine, Pinus pinaster. Coating of amphorae used for wine with pitch to improve impermeability was reported by multiple Roman authors and also alluded to by Brassavola. However, more recently physical evidence has called for a critical re-assessment:
Kerlijne Romanus, et al., "Wine and olive oil permeation in pitched and non-pitched ceramics: relation with results from archaeological amphorae from Sagalassos, Turkey,"
Journal of Archaeological Science, Volume 36, Issue 3, 2009, pp. 900-909:
Against this background, the possible uses of the Sagalassos amphorae are discussed, and the traditional association of pine pitch with wine storage in archaeological amphorae is critically assessed.
Resin could be processed into pitch by various processes, such as dry and wet distillation, as well as boiling in water followed by straining. Regarding the inferior quality of pix Hispana mentioned by Pliny, in the publication
Pedro A. Lillo Carpio, "Pix y oleum ligni, productos industriales basicos en la antigüedad y su pervivencia," Revista Murciana de Antropologica, No. 1, 1994, pp. 109-119
the author speculates that it might have had something to do with dry distillation at high temperatures (to maximize yield? NJ):
Posiblemente los defectos de la pix hispana de debian a que obtenia a base de calentar la madera excesivamente y sobre todo porque no era sometida al proceso de hervirla en agua u colarla despues, tarea por la que sabemos que se obtenia la pez blanca -- pix alba -- mas pura, menos olorosa y sin particulas carbonosas.
My translation: "Possibly the shortcomings of pix Hispana were due to the fact that it was obtained by excessive heating of the wood and in particular because it was not subjected to the process of boiling in water followed by straining, a process that we know was used for obtaining white pitch, pix alba: purer, less odorous, and without carbonized particles."
As for medicinal uses of pix Hispana, Rudolf Kobert, Historische Studien aus dem Pharmakologischen Institute der Kaiserlichen Universität Dorpat,
Halle an der Saale: Tausche & Grosse 1896, p. 67, cites the Roman physician Scribonius Largus as recommending both pix Hispana and pix Bruttia for wound dressings.