Fact check: It's said that there is 15 physical causes of color, but is there more?

1. Summary of the results

The statement about 15 physical causes of color is scientifically accurate and well-documented. This classification comes from Kurt Nassau's book "The Physics and Chemistry of Color: The Fifteen Causes of Color" ^[1]. All sources consistently confirm this number, though they emphasize that while there are 15 distinct causes, they can be grouped into broader categories.

2. Missing context/alternative viewpoints

The original statement misses several crucial pieces of context:

• These 15 causes are actually organized into 5 major categories ^[1]:

1. Vibrations and Simple Excitations

2. Transitions Involving Ligand Field Effects

3. Transitions Between Molecular Orbitals

4. Translations Involving Energy Bands

5. Geometrical and Physical Optics

• More specifically, these 15 groups are divided into ^[2]:
• First 3 groups involving energy level transitions
• Next 4 groups involving ligand field and molecular orbital theories
• Following 4 groups using energy band formalism
• Final 4 groups explained by geometrical and physical optics theory
• It's important to note that all occurrences of color involve electron excitation at their most fundamental level ^[2]. The 15-group classification system was created to simplify the explanation of these complex phenomena.

3. Potential misinformation/bias in the original statement

The original statement's phrasing might lead to some misconceptions:

• It suggests these are purely "physical" causes, when in fact they encompass both physical and chemical mechanisms ^[2]
• It presents these 15 causes as separate entities, when in reality they are interconnected and based on the same fundamental principle of electron excitation ^[2]
• The simplification into 15 distinct causes, while useful for educational purposes, might oversimplify the complex nature of color phenomena