Preface ————————————–    next page
1. Introduction — —————————–         p.  1
2. What Photons Are ————————–     p.  2
3. Photons Are Polarized ——————–      p.  7
4. Photons Diffract —————————       p. 10
5. Photons Radiate —————————-      p. 13
6. Photons Are Reflected ——————       p. 16
7. Photons May Be Scattered ————-      p. 20
8. Photons Are Disobedient —————      p. 21
9. The Trouble With Photons ————-      p. 22
10. Photons Get Refracted ——————     p. 24
11. Where Photons Came From ———-     p. 30
12. Photons as Retinal Images ————-    p. 37
13. Photons Catalyze ————————–       p. 41
14. Light ———————————————    p. 44
15. Photons Vary in Visual Effectiveness    p. 48
16. Distinguishing Photon Wavelengths    p. 53
17. Another Problem with Photons ——-    p. 58
18. Photons Can Fool You ——————-      p. 64
19. Beyond Photons, the Visual Image-–    p. 66
20. Measuring Photons ———————–     p. 74
21. Measuring Light —————————       p. 79
22. Light Meters ———————————-     p. 82
Epilogue ———————————————-   p. 87
References and Notes ————————-     P.. 88
Appendix: Schematic Brain Diagram —–    p, 91


This graphic essay began as a draft for part of a course being developed by the Canadian National Committee of the International Commission on Illumination. The course’s objective is to promote the study of illumination engineering (There’s a shortage – see end note 6.) and to increase general understanding of light and lighting. Having taught perception courses since graduate days, I had 50 years of notes about vision. Recruited from physics into psychology by Gillray Kandel at Rensselaer, those notes included more than the minimal basics about how light makes vision possible. So I offered to draft something about how the physics of light relates to vision.

A subtitle, “A Glance at the Dance of Photons” came while awakening one morning. Then I realized how well it captures the theme: that photons vibrate, that they scatter and “bounce” all over place, that their “dancing” causes them to swerve when passing from one media to another – swerving that enables focusing them into images; and that their waving transfers their energy initiating a cascade of molecular changes which convey the information in an image to the brain. As the title, its poetry may capture more attention.


Glance at the Dance of Photons Copyright © 2022 by Thomy Nilsson. All Rights Reserved.

Share This Book