Europhys. Lett.
Volume 71, Number 3, August 2005
Page(s) 487 - 493
Section Interdisciplinary physics and related areas of science and technology
Published online 13 July 2005
Europhys. Lett., 71 (3), pp. 487-493 (2005)
DOI: 10.1209/epl/i2005-10107-2

On the limits of digital video microscopy

J. Baumgartl and C. Bechinger

2. Physikalisches Institut - Pfaffenwaldring 57, 70550 Stuttgart, Germany

received 28 April 2005; accepted in final form 9 June 2005
published online 13 July 2005

We explore the limits of digital video microscopy which is established as a standard method in physics, chemistry and biology. At particle distances close to contact we observe small but systematic deviations between the optically measured and the real particle distances. This difference is caused by the overlap of the optical images between neighboring particles. Exemplarily we discuss the consequences of this effect on pair potential measurements of charge stabilized colloids in confined geometries.

82.70.Dd - Colloids.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
61.20.-p - Structure of liquids.

© EDP Sciences 2005