Earhart Project Research Bulletin
July, 2002
Artifact 2-6-S-45

Secrets of the Knob

Symbol #13

Analysis and photos courtesy Jeff Glickman, Photek Imaging.


This is an analysis of photomicrographs of symbol #13 on TIGHAR artifact 2-6-S-45, commonly known as “the knob.” The photos are visually degraded because of the JPEG format which is used to enable email transmission.

This analysis contains 5 images which are separately annotated. Multiple photomicrographs using multiple illumination angles were used because of the ambiguity in this symbol. Symbol #13 is heavily encrusted, and slightly damaged.


Knobref: This is symbol #13 extracted from KnobRef.jpg. The lighting used was diffuse from above. There is a strong line near the bottom. This feature combined with shadow located to the right of the top inner circle, suggest this symbol may be a "2."

Original 54:

Note 1. Concavity on left-hand edge.

Note 2. Flow from lower-right edge.

Original 55:

Note 3. Concavity with possible fracture on right-hand edge.

Note 5. Possible physical insult against symbol.

Original 56:

Note 4. Flow from upper
right edge.

The strong line visible in “knobref” appears to be unique to this one photomicrograph. The two internal circles, combined with the concavities 1 and 3, exclude all numbers except “8.”

Conclusion: The symbol features suggest TIGHAR artifact 2-6-S-45 symbol #13 most likely is an eight (“8”).


Jeff Glickman • Photek • Board Certified Forensic Examiner • Fellow, American College of Forensic Examiners • 503-949-6200

Symbols #1-11, 19 Symbol #12 Symbol #13 Symbol #14
Symbol #15 Symbol #16 Symbol #17 Symbol #18
Preliminary Letter of Opinion

Archived Research Bulletins Earhart Project Home Page

About TIGHAR Join TIGHAR TIGHAR Projects TIGHAR Publications Contract Services
The TIGHAR Store Blog TIGHAR Forum Contact TIGHAR TIGHAR Home

Copyright 2017 by TIGHAR, a non-profit foundation. No portion of the TIGHAR Website may be reproduced by xerographic, photographic, digital or any other means for any purpose. No portion of the TIGHAR Website may be stored in a retrieval system, copied, transmitted or transferred in any form or by any means, whether electronic, mechanical, digital, photographic, magnetic or otherwise, for any purpose without the express, written permission of TIGHAR. All rights reserved.

Contact us at: info@tighar.org  •   Phone: 610.467.1937   •   JOIN NOW