Manganese has played a pivotal role in the creation and application of pigments throughout art history. From the prehistoric use of manganese dioxide in brown pigments like umber to modern pigments like manganese violet and manganese blue, this lesson explores the composition and X-ray fluorescence (XRF) spectral characteristics of these pigments.
Objectives
- Identify the role of manganese in pigments like raw umber, burnt umber, manganese violet, and manganese blue.
- Differentiate between the spectral signatures of manganese and other elements (e.g., iron, barium)
Materials
- Pigments Checker Standard (raw umber, burnt umber)
- Pigments Checker Modern Art (manganese violet, manganese blue)
- XRF spectrometer with low-keV filter setup.
Lesson Plan
1. Introduction to Manganese in Pigments
- Highlight the distinction between umber and sienna pigments based on manganese content.
2. Raw Umber and Burnt Umber Analysis
- Examine umber pigments and their composition of manganese dioxide and iron oxide.
3. Manganese Violet
- Introduce manganese violet (manganese ammonium pyrophosphate)
- Analyze its spectrum to observe the dominance of manganese K Alpha line.
4. Manganese Blue
- Explore the composition of manganese blue (barium permanganate) and its historical use before discontinuation in the late 20th century.
- Use XRF analysis to distinguish between manganese and barium peaks in the spectrum, noting the reduced manganese signal relative to other pigments.
