Digital camera densitometry

J. Martinez-Irujo jjmirujo at
Tue Mar 13 04:38:22 EST 2001

Dima Klenchin wrote:

> Philip Aisen <aisen at> wrote:
> :If anyone has had favorable experience with digital camera densitometry
> :of Westerns and SDS gels I would appreciate hearing about the camera and
> :software used.
> No fancy setup here. Cheap HP scanner, and any software that
> can count pixels in a selected area (NIH image, Adobe Photoshop -
> in fact most bitmap editing programs can do it). Whether you have
> this simple solution or an expensive specialized setup, in order to
> claim quantitative results you must have internal calibration curve
> on the same gel/blot. As long as calibration is present and is
> reasonable, it completely does not matter how you obtained it - no
> matter what, Westerns are intrinsically highly non-linear.
>         - Dima

I absolutely agree. If you prepare a standard curve to calculate protein
concentration do the same with your gels. Load several dilutions of the same
sample and use them as standard. You may find funny to play with image
analysis software, but no reliable results will be obtained in the absence of
an internal calibration (even with that expensive equipment you can not
afford). On the other hand, and in the presence of a calibration curve, who
needs any equipment to quantitate?

And remember than most systems work with visible light, so do not expect to
find any difference  your eye do not see...

Juan J. Martinez Irujo
Depart. de Bioquímica
Universidad de Navarra


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