Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Red eyes 
Name: kano
Location: N/A
Country: N/A
Date: N/A
Question:
What causes red eyes when you take a picture of someone?


Replies:
There is a reflection of the flash off of the back of the retina - the blood vessels in the retina make the red light seem predominant.

Ellen Mayo

To prevent this, fancy new cameras have an anti-red-eye feature. The flash strobes at low power for a second before the picture is actually taken. The light causes the subject's pupils to constrict, so that when the picture is taken you don't see much of this reflection.

--ProfBill


Click here to return to the Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory