I don't use Adobe Photoshop, but if you have a linear response between
amount of RNA loaded and 'densitometry' data, I don't see how anyone
can argue with you. One thing you could do which might avoid reviewer
gripes is to calibrate your system with a photographic step tablet,
e.g. StepTablet No. 3 from Kodak (- no affiliation). These are strips
of film exposed in such a manner to give a range of predetermined
O.D.s, which you could scan to find out exactly how good or bad your
densitometry system is.
(all views expressed
are strictly my own)
Martin Hoyt (rdlab at gandalf.bio.uci.edu) wrote:
>We recently began using Adobe Photoshop to quantitate signals on
>Northern blots after we lost access to a densitometer. We determined
>a range of total RNA loaded in which the signals from our mRNAs of
>interest were linear, and the data we obtained using the scanner +
>Photoshop agreed with our earlier densitometry data. A colleague who
>used similar quantitation methods recently had problems with a
>reviewer who said this quantitation technique was not valid.
>My question is: Can Photoshop validly be used to quantitate signals
>on autoradiographs? If so, what conditions/guidelines must be
>followed? Also, any relevent references would be appreciated.