This lesson focuses on the role of iron in art. Iron is a ubiquitous element found in many traditional and modern pigments, such as ochres and Prussian blue. Understanding how iron contributes to the composition and detection of these pigments provides valuable insights into their identification.
Objectives
- Understand how different pigments, such as vivianite, yellow ochre, red ochre, and Prussian blue, exhibit iron signals during analysis.
Materials
- Pure iron metal cube
- Filters for X-ray analysis (low-keV and routine filter setups)
- Pigment samples from Pigments Checker (vivianite, yellow ochre, red ochre, and Prussian blue)
Lesson Plan
1. Baseline Measurement with Pure Iron
- Begin the analysis with a pure iron metal cube to establish a baseline signal.
- Compare results using two filter setups: low-keV and routine filter.
2. Analysis of Iron-Containing Pigments
- Vivianite:
- Introduce vivianite as a hydrated iron phosphate used in medieval wall paintings, especially in Northern Europe.
- Yellow Ochre:
- Describe yellow ochre as a hydrated iron oxide hydroxide and observe its spectrum, showing a lower iron peak due to the natural mixture of iron minerals with quartz, clay, and other impurities.
- Red Ochre:
- Explain red ochre as an iron oxide with similar characteristics to yellow ochre.
- Prussian Blue:
- Discuss the historical significance of Prussian blue as the first modern pigment, popular from 1724 onward and analyze its spectrum, showing an iron peak intentensity in the same range as ochre pigments.
