In the 1960s and early 1970s, Morgan W. Phillips at the Society for the Preservation of New England Antiquities (SPNEA) became involved with historic paint and color analysis, at the Harrison Gray Otis House in Boston.
In the early 1970s, Frank S. Welsh joined the National Institute of Standards and Technology in Philadelphia and began to study historic paints with Batcheler.
Smaller companies such as John Canning: Perfecting Finish also specialize in historic paint analysis and most have websites detailing their services and publications.
[2] It is often more effective to make a small crater with a knife and then to sand the edges to a gradual slope, the paint layers widening as the surface is rubbed down.
[4] In past and recent analysis, paint researchers have become increasingly aware that the samples removed from the site for study may not represent the true historic color.
At lower temperatures, "materials such as varnishes, lacquers, wood, oil, alkyd, and acrylic paints are especially at risk and need to be handled with extreme care".
Housekeeping is essential for preventative care: for example, with more attention to climate and pollution, these studies can help decrease the pigment deterioration of historical buildings and sites.
For interior spaces, mechanical control of internal temperature, light, and humidity through an HVAC system and good conservation care will help decrease the amount of pigment biodegradation.
The second is to leave the samples in a loose condition with their broken surfaces which then can be manipulated under the microscope to permit a variety of views of the layers.
This is perceptual shift can produce inaccuracies in ‘reading’ the paint sample under different lighting conditions, and cause what is referred to as a ‘metameric match’.
While conventional instruments were typically too large for transport, computer software now makes this technology portable, allowing for more accurate readings to be taken in situ.
The hues are identified by initials indicating the central member of the group: red R, yellow-red YR, yellow Y, yellow-green YG, green G, blue-green BG, blue B, purple-blue PB, purple P, and red-purple PR.
Selection often weighs factors such as economy and durability, use of a high-quality standard paint from a local or national company and application by a qualified contractor.
Color choices may be based on paint research reports prepared for interior rooms or exteriors of comparable date and style.
During rehabilitation, care should be taken to retain or restore selected portions of the decorative work as well as the color matching process, to evoke the historic sense of time and place.
Based on historical research, onsite collection of paint samples, and laboratory analysis, surface colors and treatments can be recreated to reflect the property at a particular period of time.
Investigations carried out by Susan Nashof by simple scraping and revealing of older finishes of buildings yielded a palette that became popularly known as Williamsburg colors.
The date, or period of a building can be sourced from the materials identified within the layers of pigment or finish, from a specific stylistic feature or technique, or historical records and evidence.
As the tools, techniques, and methodologies of historic paint samples evolve, so do the complexities involved in interpretation as nuance adds to an already complicated narrative.
Interpretation requires that conservation scientists work in concert with architectural historians to decipher the stratigraphic record, not only to consider the taste and preferences that informed paint selections, but the social, political, and economic climate of their manufacture and consumption as well.
Mat Webster, executive director for Granger Department of Architectural Preservation and Research at Colonial Williamsburg joins Moffit in noting that samples collected of a deeper, more intense hue are derived from costly pigments imported from England (and initially globally sourced).
Referencing a sample taken from an 18th-century colonial home in Williamsburg, Virginia, Moffit explains that the underlying layers on both hinge and door were initially painted in the same color, in keeping with the aesthetic of their time.
However, analysis of a subsequent layer exposed an incongruous black and white schema, indicating a failed attempt at a colonial revival aesthetic.
[24] Without proper understanding of the historic record, these samples might lead to false conclusions if obtained through inferior “scratch and match” methods and visual inspection alone.
Color shift can pose a problem to the conservator tasked with restoring a structure to its authentic appearance when the altered condition is understood as the intended schema- especially when based on older “scratch and match” assessments described above.
Still, others like Architectural Conservator Tania Alam argue for a more flexible interpretation of the past when authenticity runs counter to the cause of structural preservation.
Alam cites the work of architect and designer Alexander Girard in his 1961 successful bid for the revitalization plan of Washington Street in downtown Columbus, Indiana.
[26] Alam notes that Girard did not rely on scientific methods but simply " visualized the restoration primarily through the use of a color scheme, which would highlight the architectural features of the Victorian commercial buildings to work in tandem with the newly designed signage."
Horowitz's whimsical palette accentuated the architectural features of the buildings in question, restoring them to life and establishing the now revered Art Deco District of South Beach Miami.
However, she contends that these transgressions may be forgiven when the preservation structures rest in the balance and concludes that, "In their attempts to restore and save the historic fabric, both these color palettes essentially created new aesthetics in the respective area.