Blue Pigments in Blue and Purple Painting Layers of Gda  nsks’ Paintings of the mid-16th to the End of the 18th Century Bo _ zena Szmelter-Fausek,* Justyna Olszewska-  Swietlik Department of Painting Technologies and Techniques, Institute for the Study, Conservation and Restoration of Cultural Heritage, Nicolaus Copernicus University in Torun, Ul. Sienkiewicza 30/32, Torun, 87-100, Poland Received 14 October 2015; revised 17 December 2015; accepted 17 December 2015 Abstract: The technique of blue and purple painting layers were analyzed on the example of selected panel paintings of the mid-16th to the end of the 18th century from the Gda  nsk painting workshops. Paintings are the property of the church and the museums of Gda  nsk and Pelplin (Poland). Searching studies of the selected paint- ing layers and of the samples were performed to charac- terize the pigments present in the individual blue and purple painting layers and the pictorial techniques. Sam- ples were obtained from painting and ground layers. The blue pigments identified in Gda  nsks’ paintings of the 16th and 17th century were natural azurite, smalt, and natural ultramarine, and of the 18th century, the only one blue pigment was organic indigo. Purple layers were obtained by adding organic red, lead red, vermilion, and iron oxide red. VC 2016 Wiley Periodicals, Inc. Col Res Appl, 41, 270– 275, 2016; Published Online 19 January 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.22030 Key words: color modeling; blue and purple pigments INTRODUCTION In this work, selected worldwide famous panel paintings from the Gdansk workshops of mid-16th like epitaphs from St. Mary’s church in Gdansk and paintings by famous artists of the 17th century Golden Age: Anton M€oller (1563/5–1611), Hermann Han (1580–1627/8), and Isaac van den Blocke (before 1589–1628); and portraits of Protestant Clergymen dated on 18th century were the subject of analysis of blue and purple painting layers. Blue pigments were used to color different parts of the analyzed paintings. It was used the most often for the blue sky, blue, and purple garments. Parts in shades of blue and purple were often painted with a blue with an admixture of black pigment. Lights in blue and purple layers were obtained by adding white pigment. The object of research is the pictorial technique, used pigments, and way of modeling the blue and the purple painting layers in the Gdansk paintings. The general aim of this work is to analyze and systematize of how the tech- nique and the technology of painting the blue and the purple layers containing blue pigments had been changing from the mid-16th to the end of the 18th century. METHODOLOGY Samples About 26 micro-samples were taken from blue and pur- ple parts of 13 paintings by Gdansk artists (Table I). The numbers given at the cross-sections of the samples under visible and ultraviolet light denote the technological layers, beginning from the ground layer and up to the var- nish. The samples collected represent blue and purple hue in the painting composition. The cross-sections of the samples were prepared by embedding the samples in a small resin block (acrylic resin ‘Duracryl 0’ Spofa Dental – Praha) and polishing. Materials methods of measurements of the painting technique of Gdansks artists that were the subject of *Correspondence to: Bo_ zena Szmelter-Fausek (e-mail: Bozena_Szmelter@ Op.Pl) Contract grant sponsor: Polish National Science Center of the Ministry of Science and Higher Education; contract grant numbers: N N105 430940, N N204 370340 to J.O.-  S. VC 2016 Wiley Periodicals, Inc. 270 COLOR research and application