Selenium is a rare element in pigments and it is just found in cadmium red, a vibrant red-to-orange pigment widely used in modern art. This lesson will explore the composition, history, and identification of cadmium red, focusing on its selenium content and the role of XRF spectroscopy in its detection.
Objectives
- Understand the composition and properties of cadmium red.
- Recognize the historical significance of cadmium red as a replacement for vermilion.
- Interpret XRF spectra to detect selenium peaks associated with cadmium red.
Materials
- Cadmium red sample included in Pigments Checker STANDARD.
- XRF spectrometer with routine filter setup.
Lesson Plan
- Introduction to Cadmium Red
- Explain cadmium red as a cadmium sulfo-selenide pigment.
- Highlight its historical use as a safe replacement for vermilion (mercury sulfide) in the 19th century.
- Selenium and Cadmium Red
- Emphasize selenium’s role in cadmium red and its absence in other art pigments.
- Introduce the spectral properties of selenium: K-alpha peak at 11.2 keV and K-beta at 12.5 keV.
