DNA concentration - (Jun/15/2005 )

Hi
I do not know how to calculate the DNA concentration without using UV spectrophotometer.
Is there a method for calculating the DNA concentration by looking the agarose gel photos.

Thank you

My favorite way is to run 1ug of HindIII digested lambda dna as a marker. Compare the intensity of my band of interest to the band it most closely matches on the HindIII digested lane. Estimate concentration that way.