{"id":3763,"date":"2012-06-01T11:24:46","date_gmt":"2012-06-01T16:24:46","guid":{"rendered":"http:\/\/www.conservators-converse.org\/?p=3763"},"modified":"2012-06-01T11:24:46","modified_gmt":"2012-06-01T16:24:46","slug":"40th-annual-meeting-psg-session-may-9-relating-artist-technique-and-materials-to-condition-in-richard-diebenkorns-ocean-park-series-by-ana-alba","status":"publish","type":"post","link":"https:\/\/resources.culturalheritage.org\/conservators-converse\/2012\/06\/01\/40th-annual-meeting-psg-session-may-9-relating-artist-technique-and-materials-to-condition-in-richard-diebenkorns-ocean-park-series-by-ana-alba\/","title":{"rendered":"AIC’s 40th Annual Meeting – Paintings Session, May 9, “Relating Artist Technique and Materials to Condition in Richard Diebenkorn’s ‘Ocean Park’ Series” by Ana Alba"},"content":{"rendered":"

When Ana Alba was working at the Hirshhorn Museum she undertook a research project on four paintings from Richard Diebenkorn’s “Ocean Park” series. \u00a0Her study compared the materials used in each of the paintings and assessed how that tied in to their current condition. \u00a0She presented her findings at the 2010 annual meeting in Milwaukee, Wisconsin. \u00a0Two of the paintings had severe cracking while the other two were in good condition; the paintings with the cracking had an acrylic preparatory layer. \u00a0At this year’s annual meeting she presented research conducted at the National Gallery of Art that expanded upon her intial study.<\/p>\n

Ana’s current research involved the examination of more than 45 paintings and samples for analysis were collected from approximately 15 paintings. \u00a0All of the information gathered was compiled into an extensive chronological database. \u00a0An additional list of travel histories with photographic references was completed. \u00a0The results of this study showed changes in the artists materials both between paintings and within individual works.<\/p>\n

Diebenkorn worked for weeks to years on some of his paintings. \u00a0He painted consistently on unsized cotton duck but his choice of preparatory materials fluctuated over time. \u00a0Between 1968 and 1973 he used white acrylic gesso and toned it with diluted acrylic. \u00a0In some cases he added alkyd. \u00a0From 1973 to 1978 he transitioned from white to clear preparatory layers, presumably in order to maintain the raw canvas color and achieve transparencies in his paint layers. \u00a0Scientific analysis suggested the clear material was synthetic and consistent with Rhoplex AC-33. \u00a0This was more or less confirmed by photographic evidence of showing large jugs labeled as Rhoplex located in the artist’s studio. \u00a0By 1979 Diebenkorn had returned to using acrylic gesso almost exclusively.<\/p>\n

Diebenkorn primarily painted with acrylics and alkyds. \u00a0He added oils sparingly and extended his paints as far as possible. \u00a0He also used charcoal, graphite, and colored pencil to define his images. \u00a0Infrared reflectography of his paintings show numerous alterations in his compositions, which is unsurprising given his appreciation of layering and the amount of time he spent working on each piece. \u00a0Once a painting was finished he applied matte fixative to the surface. \u00a0In his early works he applied this in 6 or 8 consecutive layers that left a glassy, heavy surface. \u00a0Eventually he shifted his process and masked out the painting to limit application to the charcoal areas.<\/p>\n

The condition assessment of this larger group of paintings seem to support the findings of Ana’s initial study. \u00a0Paintings executed between 1960 and 1973 vary and some show some cracking. \u00a0The cracks follow drawn lines, compositional changes, and are greatest on the paintings with heavy layers. \u00a0Paintings completed after 1973 and before 1980 have heavier, more pronounced cracking with broad and isolated areas of cupping. \u00a0These paintings follow the same trend as the earlier works with the greatest cracking located in the layered areas. \u00a0Diebenkorn’s paintings after 1980 are in much more pristine condition with less cracks. \u00a0The trend of this condition timeline show that the paintings in the poorest condition are located in the middle of the Ocean Park series. \u00a0This supports previous findings by showing that paintings with Rhoplex and acrylic exhibit the worst cracking, especially when they are painted thickly with numerous layers.<\/p>\n

This study highlights concerns regarding some of Diebenkorn’s selection of materials. \u00a0Alkyds are brittle so putting them over flexible preparatory films and unsized canvas makes them susceptible to cracking from impacts and physical movement of the substrate. \u00a0Fortunately, they do not seem prone to delamination so the cracking does not lead to significant paint loss. \u00a0In addition, when Diebenkorn diluted his materials he reduced their strength. \u00a0That left them with a greater chance of deformation in response to physical and environmental factors.<\/p>\n

Ana pointed out that there are some limiting and extenuating factors to consider in this research. \u00a0The are as follows:<\/p>\n