User:Sblais/BPG Lead White

THIS ENTRY IS A DRAFT

Lead white paint (also known as flake white) was used as early as the 4th century B.C. until the invention of zinc white and titanium white in the 19th century, where it was gradually phased out. It is historically the most important of all lead pigments and of all white pigments. The basic lead carbonate can darken to a gray, brown or black, occasionally to an orange-pink, lead sulphide when in contact with sulphide pigments (e.g. vermillion) or when exposed to atmospheric sulfides. It can be converted back to a white pigment, lead sulphate, with dilute, hydrogen peroxide.

Occasionally it is observed that converted lead whites "appear" to revert to a gray state. Darkened lead whites cannot always be successfully converted to a white pigment. Lead which which has gone "completely" black seems most resistant. Application of hydrogen peroxide for the conversion may only turn such pigment pale gray. Literature has also shown that the paint film is affected by the application of hydrogen peroxide.

• Examples of paper objects containing darkened lead white. All images are part of the public domain.
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  "Sheep", 1861, Rosa Bonheur. Brush and brown wash over graphite, heightened with lead white (partially oxidized to pink). The Cleveland Museum of Art (1915.716).

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  "The Nativity with the Dream of Joseph", c. 1527/30?. Parmigianino (Italian, 1503–1540). Pen and brown and black ink and brush and brown wash, with traces of brush and black wash, heightened with lead white (oxidized). The Cleveland Museum of Art (1924.1003)

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  Copy after Giulio Romano's Fall of Icarus, after 1536. After Giulio Romano (Italian, 1492/99–1546). Pen and brown ink and brush and brown wash over red chalk, heightened with lead white. The Cleveland Museum of Art (1992.90).

Historical Use

Other Names for Lead White

• Flake white (which comes from the historical Dutch manufacture process)
• Cremnitz white
• Krems white
• Vienna white
• Berlin white
• Silver white
• Slate white
• Cerusa (or cerrussa),
• Hydrocerussite (modem mineralogical name)

In other languages:

In other languages:

• English: lead white (sometimes white lead)
• French: blanc de plomb
• German: Bleiweiss
• Italian: bianco (biacca) di piombo
• Spanish: plomo blanco

Dutch Manufacture

Today's manufacture of lead white uses a rapid chemical process, but the historical "Dutch" manufacture was previously used for centuries. In the Lead White chapter of Artists' Pigments, the authors describe the historical process:

Until recently, lead white was made by the "Dutch" or "stack" process which, so far as we know, differs little in principle from the method used in classical or medieval periods. Metallic lead in the form of strips or "buckles" [...] was exposed from one to three months in specially made clay pots which had a separate compartment in the bottom to hold a weak solution of vinegar (acetic acid). The pots were stacked in tiers in a shed with fermenting horse manure or waste tan bark, which produced both heat and carbon dioxide . The combined action of acetic vapors, carbonic acid, and heat slowly transformed the exterior of the lead to white basic lead carbonate. The flaky product was scraped from the surface and after washing, drying, and screening was ground directly in linseed or other drying oil. [...] [Lead] white was manufactured in England in the seventeenth century; in 1622 a monopoly was granted for making both white and red lead. [...] [Some] of the early recipes call for total immersion of the lead in vinegar or suspension over vinegar in closed pots so that only lead acetate could be produced in the first step. Carbonation apparently was done later by roasting the initial product.

Factors to Consider

It is worth noting that converting blackened lead white is a purely aesthetics-driven treatment with visual improvement remaining an indicator of success, often enabling the study and display of previously un-exhibitable works of art. This is not a preventive treatment. (citation?)

Potential issues

Incomplete Conversion

Lussier, S. and G. Smith. A review of the phenomenon of lead white darkening and its conversion treatment, Studies in Conservation. 2007. 52: 41-53

Disruption of Media

Pigments become more brittle/friable: Lussier, S. An Examination of Lead White Discoloration and the Impact of Treatment on Paper Artifacts: A Summary of Experimental Testing. The Book and Paper Group Annual, 25: 9-12.

Fading of other media: Mowery, F.: The conservation of the Omenhauser Civil War sketchbook. The Book and Paper Group Annual. Vol. 10, Robert Espinosa, (compiler), 1991: 139−148.

Disruption of Paper

Local oxidation

Luise Raab, Ute Henniges and Irene Brückle* Eliminating Hydrogen Peroxide Volatiles after Lead White Conversion Treatment Via Sorption Agents. Restaurator. 2020. 41(2): 101–117

Muller, E. et al. Conversion of Discolored Lead White: Effects of Hydrogen Peroxide on Paper and Paint. Journal of Paper Conservation. 2022. 23(3): 90-101

Reoccurence

The drawing The Virgin and Child with Saints John the Evangelist, Anne (?), Joseph, and a Female Saint by Giulio Clovio (fig. 9) was part of the recent exhibition, Michelangelo and His Influence: Drawings from Windsor Castle, which traveled to five venues. It was executed in gray chalk and gold paint on laid paper. A small patch of lead white gouache is located on the right hip of the Child. The paint is thought to have been used to obscure an imperfectly drawn passage of the Child's torso, or possibly to cover a defect in the primary support. In 1995, before being reproduced for the exhibition catalogue of the same title, the drawing was examined and lead white oxidation was observed. The discolored paint was treated with ethereal peroxide, and reverted to white. By mid-1996, the paint had become black again. A second peroxide treatment reconverted the lead sulfide to lead sulfate and the drawing was framed for exhibition. After exhibition at the second venue, a "noticeable grey creeping around the edges of the patch" was noted. Three days later, after travel to the third venue, The Art Institute of Chicago, the patch was "thoroughly grey-black, although it had been transported in sealed cases amongst other drawings with a sheet of Artsorb." On the basis of the characteristics of the Clovio drawing, the nature of the media, and the reactive nature of lead sulfate, the gel technique for peroxide-induced reversion presents an attractive treatment option, and one that will likely be explored in the near future. Further research will determine the extent to which the protective properties of peroxide gels will inhibit recurrent oxidation.

Conversion Treatment Methods

Ether

Ethereal peroxide is a historic technique that has been described in the literature as the “standard method.” In this method, a relatively high concentration of aqueous peroxide solution (between 6% to 50% w/v) is shaken vigorously with an equal amount of diethyl ether. The container is then allowed to sit until the mixture separates into two phases, with water below and ether in a distinct upper layer. Due to its slight affinity, a few molecules of hydrogen peroxide will remain in the ether and can be applied in a non-aqueous manner. The conservator would carefully dip a brush into only the upper layer of ether and apply it to the discolored lead white. This technique allows non-aqueous application, so it may avoid swelling or solubilizing a water-based paint film. However, some practitioners have reported that this application method may still cause the paint film to solubilize (Couch, 1985) or rupture (Lussier, 2006). The ethereal method has largely been replaced by other methods, at least in American conservation labs, due to the toxicity of the diethyl ether and the effectiveness of other options. This treatment should only be performed in a fume hood or under equivalent ventilation.

Brush (aqueous)

Direct brush application of hydrogen peroxide is a simple and effective method in many cases. A concentration of 1%, 2%, or 3% w/v is used. The peroxide is applied carefully to the affected media with a very small brush. Some areas may require multiple applications. This method may be modified with ethanol to increase penetration throughout the paint film, either by mixing an ethanol and peroxide solution or by pre-wetting the area with ethanol prior to application. Of course, the increased penetration allowed by the ethanol can also result in the peroxide penetrating into the paper substrate. There is also a risk of swelling or solubilizing water-based paint films.

Methylcellulose

Cellulose ethers such as methylcellulose or hydroxypropylcellulose may be used as a modification of the brush application. A dilute solution of hydrogen peroxide is mixed with 1-3% cellulose ether to create a gel. The gel is applied to the affected media and rewetted with deionized water as needed. Following treatment, the gel is removed by repeated application of deionized water and careful blotting. An article on the cellulose ether technique (McFarland, 1997) found that it offers faster and more complete results than a similar concentration of peroxide without a gelling agent. This technique offers several benefits: it holds the peroxide in contact with the discolored pigments longer; it reduces the risk of peroxide wicking into the paper support; it may reduce the number and time of applications needed; and it appears to minimize disruption of the paint film. McFarland acknowledges that some cellulose ether residues may not be removed, however, she argues that this can be a benefit because lead white paint films often suffer from flaking or friability, so the residual cellulose ether film can act as a consolidant.

Vapor

Vapor application of peroxide can be extremely successful and requires relatively less conservator time when the discolored lead white is finely dispersed and present over a larger area of the object. The object to be treated is placed in a sealed chamber with a dilute solution of hydrogen peroxide (as little as 3%). Risk of unintentional contact can be reduced by containing the peroxide in a saturated non-woven fabric at the bottom of a flat plastic tray while the object is held safely above on a plastic grate. Color changes can be monitored through a clear acrylic sheet that closes the chamber when rested on the tray. Vapor exposure can also be limited by covering the artwork with a clear polyester sheet (Melinex or Mylar) with cutout openings exposing the discolored areas. Alternatively, a small local vapor chamber can be created over a specific area by inverting a glass container with a peroxide-soaked blotter fixed at the bottom [...]. The exposure time in the vapor chamber can range from two to twelve hours, depending on the severity of the discoloration. The reaction is slow, but the conservator can monitor the progress while working on other projects, so this can be a relatively efficient approach to widespread discoloration. Although the object is exposed to elevated humidity, the paint is not fully wetted out so the vapor application technique can be used on water-sensitive media. This technique may not be appropriate for all objects because it will result in humidification of the artwork as well as peroxide exposure to a larger area of the paper support and other media.

Rigid gels (agarose)

Peroxide can be prepared in a rigid gel such as agarose for extremely controlled local application. Rigid gels allow the conservator to limit the moisture exposure, keep the peroxide in contact for a longer period, and to apply the peroxide to very precise areas by cutting it into the desired shapes. Good contact between the gel and the paint layer is vital. The concentration of the gelling agent should be adjusted based on the absorbency of the paint film and the paper substrate. Agarose gel with peroxide is prepared by heating a slightly more concentrated than desired agarose solution to 80 degrees Celsius to fully hydrate the agarose, allowing the solution to cool to approximately 50-60 degrees Celsius, then stirring in concentrated hydrogen peroxide and quickly casting it into a sheet. Typical final concentrations of peroxide within the gel range from 3% to up to 7%.

Agarose with peroxide recipe

It is best to keep your cast gel refrigerated and covered with another mylar sheet or plastic wrap while you work. Take only a small amount out at a time and cover that dish at your desk while you are working. The longer the hydrogen peroxide is exposed to the air, the more it breaks down and your percentage will decrease.

This recipe is for a very small area, since the peroxide is not stable. The shelf life of this is only a few days to ensure potency.

Recipe steps

The following recipe makes 24mL of a 1% hydrogen peroxide solution in a 3% agarose gel using non-stabilized, food grade 12% hydrogen peroxide.

1. Place a sheet of mylar on a heat-safe surface.
2. Measure out 2mL of 12% hydrogen peroxide into a graduated cylinder and set aside.
3. Measure 0.72g of agarose powder.
4. Add the agarose powder to 22mL of room temperature deionized water in a 100mL beaker.
5. Stir the solution to disperse the agarose powder in the water.
6. Place the beaker in a microwave and heat a few seconds at a time until the solution is completely clear. Stir if necessary to make sure the powder is completely absorbed in the water.
7. Remove the beaker from the water and let it cool down to 55-60°C. (just in the range where it is not too hot but not quite solidified).
8. Pour the hydrogen peroxide measured in step 2 into the beaker of agarose and gently stir.
9. Immediately pour on the mylar sheet and allow it to solidify down to room temperature.

The quantities of agarose powder, deionized water and hydrogen peroxide will depend on the desired concentrations of the resulting gel and hydrogen peroxide. A lower percentage gel will be wetter, and a lower percentage hydrogen peroxide will convert more slowly.

Table: Amounts needed for a 24mL, 3% agarose

Use 0.72g of agarose powder regardless of the hydrogen peroxide concentration. Use either a 12% or 30% hydrogen peroxide in the table below.

Resulting hydrogen peroxide concentration (%)	Deionized water (mL)	12% hydrogen peroxide (mL)	30% hydrogen peroxide (mL)
1	22	2
	23.2		0.8
2	20	4
	22.4		1.6
3	18	6
	21.6		2.4
4	16	8
	20.8		3.2

Bibliography

Borring, Niels et al. 2017. "The past, present and future of lead white in Denmark’s national graphic art collections". In ICOM-CC 18th Triennial Conference Preprints, Copenhagen, 4–8 September 2017. ed. J. Bridgland, art. 0508. Paris: International Council of Museums

This paper surveys the behavior of lead white in Danish graphic art collections, focusing on visual alterations and conservation approaches. It discusses the use of visual inspection, UV illumination, and condition mapping to track pigment changes in historical works on paper.

Cameo. 2024. "Lead White".

This reference entry outlines the composition, usage history, and deterioration patterns of lead white pigment. It lists analytical techniques such as X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) as standard methods for characterizing this material.

Daniels, Vincent, David Thickett. 1992. "The Reversion of Blackened Lead White on Paper". The Conference Papers Manchester. London. The Institute of Paper Conservation. pp. 109-113.

The authors explore the reversion of blackened lead white to its lighter form using controlled environmental exposure. The study monitors visual changes during the chemical conversion of lead sulfide to lead sulfate through exposure to oxidizing agents such as ozone and hydrogen peroxide vapors.

Gettens, Rutherford J., Hermann Kuhn, W. T. Chase. 1993. "Lead White" in Artists’ Pigments: A Handbook of Their History and Characteristics, Volume 2. 232 pages. Edited by Ashok Roy. pp. 67-81.

This chapter presents a historical and chemical overview of lead white, including its production methods and known degradation processes. It references polarized light microscopy (PLM), wet chemical analysis, and X-ray diffraction (XRD) as tools used in the characterization of lead white.

Goltz, Douglas et al. 2003. "Spectroscopic Studies on the Darkening of Lead White. " Applied spectroscopy 57, no. 11. pp. 1393–1398.a

This study investigates the darkening of lead white through controlled sulfur dioxide exposure and spectroscopic analysis. Raman spectroscopy, FTIR, and UV-Visible diffuse reflectance spectroscopy are used to identify the formation of lead sulfide and track changes in pigment structure.

Hansen, Birgit Vinther, Hanne Karin Sørensen. 2017. "Blackening of Lead White: Unexpected Finds on Salted Paper Prints and Lithographic Portraits". Journal of Paper Conservation, 18:3. pp. 104-108.

The article documents blackening in salted paper prints and lithographs attributed to lead white degradation. X-ray fluorescence (XRF) and microscopy are employed to detect lead-based compounds and assess the distribution and severity of the discoloration.

Hendry, Heather. 2020. "White Lead Discoloration and Conversion". Conservation Insights 2020, Indian National Trust for Art and Cultural Heritage, p. 211-217.

Hendry presents case studies of white lead discoloration and conversion treatments in paper-based artifacts. The evaluation of treatment outcomes is based on visual inspection, comparative photography, and surface condition assessment.

Hoevel, Claire L. 1985. "A Study of the Discoloration Products Found in White Lead Paint Films." The Book and Paper Group Annual. Volume 4.

This paper identifies products of lead white discoloration in paint films through light microscopy and chemical spot testing. It describes the morphological characteristics of corrosion products and links their presence to environmental exposure.

Lussier, Stephanie M. 2006. "An Examination of Lead White Discoloration and the Impact of Treatment on Paper Artifacts: A Summary of Experimental Testing. " The Book and Paper Group Annual. Vol. 25. pp. 9-12.

This study summarizes experimental treatments of lead white on paper using hydrogen peroxide. It includes documentation of results through visual observation, pH measurement, and surface inspection before and after treatment.

Lussier, Stephanie M., Gregory D Smith. 2007. "A Review of the Phenomenon of Lead White Darkening and Its Conversion Treatment." Studies in Conservation 52, no. sup1. pp. 41–53.  

This paper reviews treatment practices, historical and contemporary, for the conversion of darkened lead white, as informed by accounts in artists’ treatises, early paint chemistry manuals and the conservation literature. Analytical methods cited include Raman spectroscopy, FTIR, and SEM-EDS, used to evaluate pigment alteration and treatment efficacy.

McFarland, Margo R. 1997. "The Whitening Effects of Peroxide Gels on Darkened Lead White Paint. " The Book and Paper Group Annual 16. pp. 55-65.

This article explores the effects of peroxide gel treatments on darkened lead white in works on paper. The evaluation includes pH monitoring, UV light examination, and visual assessment of color changes and surface condition.

Mowery, J. F. 1991. "The Conservation of the Omenhauser Civil War Sketchbook." The Book and Paper Group Annual 10. pp. 139-148.

This case study describes the conservation of a Civil War-era sketchbook containing discolored lead white. Documentation and treatment were guided by visual and ultraviolet light examination, along with chemical testing of affected areas.

Müller, Emily et al. 2022. "Conversion of Discoloured Lead White: Effects of Hydrogen Peroxide on Paint and Paper." Journal of Paper Conservation. Vol. 23:3. Routledge.

This paper analyzes the impact of hydrogen peroxide treatment on discolored lead white using a combination of microfade testing, FTIR, SEM-EDS, and digital microscopy. The study evaluates the effects on both pigment and paper support over time.

Pastorelli, G et al. 2024. "Darkening of lead white in old master drawings and historic prints: A multi-analytical investigation." Microchemical Journal.  

A multi-analytical investigation of lead white darkening in historic drawings and prints. The authors use Raman spectroscopy, FTIR, SEM-EDS, and XRF to identify degradation products and examine correlations between material composition and environmental exposure.

Raab, Luise, Ute Henniges, and Irene Brückle. 2020. "Eliminating Hydrogen Peroxide Volatiles after Lead White Conversion Treatment Via Sorption Agents." Restaurator 41, no. 2. pp.101–17.  

This study examines methods for removing hydrogen peroxide residues after lead white treatment. Analytical techniques include gas chromatography (GC) for volatile detection and UV-Vis spectroscopy for monitoring chemical changes in treated samples.

Smith, Gregory D., Alan Derbyshire, Robin J. H. Clark. 2002. "In situ Spectroscopic Detection of Lead Sulphide on a Blackened Manuscript Illumination by Raman Microscopy. " Studies in Conservation. Vol. 47, No. 4. pp. 250-256.

The authors use Raman microscopy to detect and identify lead sulfide in a blackened manuscript illumination. The technique allows for non-invasive in situ analysis of deterioration products without sampling or disrupting the artwork.

Lead White Manufacture

Natural Pigments. "White Lead: Historical Uses and Information." Natural Pigments. Accessed April 14, 2025. https://www.naturalpigments.com/artist-materials/white-lead-historical.

This article goes in depth about the historical Dutch method to create lead white, with photos and SEM micrographs.

Natural Pigments. "Flake White and Cremnitz White Pigment." Natural Pigments. Accessed April 14, 2025. https://www.naturalpigments.com/artist-materials/flake-cremnitz-white-pigment.

This article goes over the difference between flake and cremnitz white, which relate to different manufacturing processes.

History of this page

This page was created in April 2025 by Sandrine Blais.