Conservation in Focus: A Camille Pissarro Drawing | Index Magazine | Harvard Art Museums document.getElementById('article-date').offsetTop"> Camille Pissarro, Eclipse of the Sun (detail), c. 1854. Graphite on off-white wove paper. Harvard Art Museums/Fogg Museum, Gift of Mr. and Mrs. Joseph Pulitzer, Jr., 1974.161. As part of our series focusing on the work of our conservation and curatorial fellows, conservation fellow Valeria Pesce describes her extensive preparation, research, and eventual treatment of a drawing by Camille Pissarro. Eclipse of the Sun (c. 1854) is a graphite drawing by Danish-French artist Camille Pissarro (1830–1903). The drawing can be attributed to an early phase of the artist’s career, created either in Venezuela—where Pissarro lived from 1852 to 1854—or shortly after, in his native St. Thomas.[1] The work is executed on western wove paper, which appears moderately thick and lightly textured. The paper support exhibited an overall discoloration, with more pronounced and uneven yellowing along the top and right edges. Following further close examination in the paper conservation lab, a treatment proposal was formulated to reduce the pronounced discoloration, which interfered with the composition’s legibility. During preliminary documentation and testing, it was observed that the graphite areas had been coated with a fixative material that showed notable fluorescence under ultraviolet (UV) light. These same areas also displayed iridescence and a subtle shimmering quality. Significantly, the fluorescent and iridescent material appears to follow the contours of the drawing itself, suggesting that this layer was likely applied with a brush or spread carefully across the paper surface and over the graphite. The discoloration was most pronounced in areas where the fixative is absent. This indicates that the fixative may have also functioned as a protective layer against direct contact with acidic materials, which is one of the primary causes of darkening and paper discoloration. Technical Examination, Documentation, and Preliminary Testing The 19th century was a period of significant experimentation in drawing, as the perception of the medium evolved from a preparatory academic exercise into an independent and experimental form of art. It is well documented that artists of the time used a variety of fixative materials to protect powdery and friable (fragile) media on paper. Examples of fixative materials documented during the 19th century include resins, milk, egg white, gelatin, and fish glue, the latter sometimes used in a more refined form known as isinglass. In the case of Pissarro’s graphite drawing, it was hypothesized—based on visual observations—that the artist may have applied the fixative himself, given the way it follows the composition. The nature of the fixative was investigated using Fourier Transform Infrared Spectroscopy (FTIR), an analytical technique used to identify organic, polymeric, and certain inorganic materials based on their absorption of infrared radiation. The analysis required taking a micro-sample from the fixative layer, along with a small number of paper fibers taken from the extreme edge of the sheet. (Conservation scientist Georgina Rayner performed this analysis.) The results indicated that the material is proteinaceous, meaning it contains protein. This finding helped inform the team’s treatment decisions: Because proteins are not readily water-soluble in cold water, washing the drawing was confirmed as a safe option. Moreover, it revealed an interesting aspect of the work’s technique. The identified material is consistent with materials used by Pissarro’s contemporaries, which further supports the hypothesis that the artist may have applied the fixative himself. The Treatment Based on the results of solubility, friability, and absorbency tests, as well as FTIR analysis, it was then decided to wash the drawing on a suction table, The table is a specialized surface connected to a pump that gently draws air and liquids downward through the material. This approach is often employed when full immersion washing could compromise the stability of the media. A control panel for the table regulates a controlled suction, allowing for better precision in both the application and absorption of water by the paper support. It also helps prevent the formation of tide lines (stains caused by water). Such localized wet treatment methods are also particularly effective in reducing uneven discoloration like the pronounced yellowing seen in this drawing. Before the treatment began, the drawing was pre-humidified under damp blotters and a membrane to relax the paper fibers and let the support expand gradually, thereby preventing cracking, tearing, or buckling upon immediate contact with water. The work was placed on multiple layers of blotting paper on the suction table. It was then washed using a fine air-compressed spray of pH-adjusted water. The mist was applied across the paper support, with particular attention given to the more discolored areas. During this process, special care was taken to redirect the spray and partially cover certain sections with blotters, because areas treated with the fixative exhibited a slower rate of water absorption and showed less discoloration compared to the uncoated part of the paper. One cleaning cycle with pH-adjusted water reduced the discoloration, but uneven yellowing continued to affect the drawing’s visual appearance. It was therefore decided to proceed with a second washing cycle. Before the second wash, a localized test was conducted using a solution of pH-adjusted water with 1% diammonium citrate (pH 6.4). Because the test reduced the stains satisfactorily, the air-compressed spray was loaded with the same solution as the one used for the test; additional localized applications were carried out with a brush as needed. Ammonium citrate solutions have recently been introduced in the field of paper conservation as washing additives to enhance cleaning treatments.[2] Their action can reduce discoloration and increase the overall lightness of the paper in cases where water alone is insufficient. The second washing cycle did, in fact, effectively reduce the remaining discoloration. The drawing was then left to dry between a soft non-woven material and felt. At this stage, the drawing was reassessed, and it was observed that its overall paper tone had significantly improved, with a marked reduction in yellowing. A final rinse with calcified water was required. The drawing was prepared on the suction table as before, and the spray was loaded with pH-adjusted water and calcium hydroxide to a pH of 7.5. Over the following two weeks, the drawing was dried and flattened between blotters and weights. The results of the treatment can be seen below. The drawing has now been brought closer to its original appearance, improving the legibility of Pissarro’s composition for all visitors to enjoy. Use the slider below to see the work transformed from before and after treatment. Valeria Pesce is the former Craigen W. Bowen Paper Conservation Fellow (2024–26) in the Straus Center for Conservation and Technical Studies at the Harvard Art Museums. [1] For the drawing's materials, see A Catalogue of the Drawings by Camille Pissarro in the Ashmolean Museum (Oxford: Clarendon Press, 1980). Regarding Pissarro's creation of the drawing, see Richard R. Brettell, Camille Pissarro in the Caribbean, 1850–1855: Drawings from the Collection at Olana (New York: New York State Office of Parks, Recreation and Historic Preservation, 1996). [2] Philine Venus, Ute Henniges, Irene Brückle, et al., “Testing Ammonium Citrates for Enhanced Washing of Paper,” Journal of the American Institute for Conservation 64 (3) (2025): 176–95.