# What is dark noise?

##### THIS GUIDE IS FOR:

Biologists whose physics is a little rusty.

##### THIS GUIDE OFFERS:

A quick review of dark noise

Dark noise is statistical variation in the number of electrons thermally generated within the pixel in a photon-independent fashion, and is the electron equivalent of photon shot noise. Dark noise is calculated from the dark current:

$Dark\ noise=\sqrt{\mathstrut (dark\ curent)(integration\ time)}$

Dark current, and therefore dark noise, are temperature dependent, with less noise at lower temperatures. For most biological experiments, dark current and dark noise are negligible over a typical exposure interval of less than five minutes.

Because dark noise is typically negligible, the main noise component coming from the camera that needs to be considered is read noise.