Phosphoimagers vs Instantimager

[Roland J Saldanha]

In talking to sales reps for the various machines it is my understanding that 
Phosphorimagers are unparalled for resolution e.g. they could easily handle 
nucleotide resolution (footprints, sequence etc) but the quantitation is 
actually semi illusionary - several technical problems make the actual 
quantitation poor some of which include, non-linear respose of the screen, 
variability within and between screens, time-dependant decay of the image on 
the screen and several artifacts due to the laser scanning.

The instantimager appears to be far superior in the quantitation but the 
resolution is poor relative to the phosphorimager and of course cannot be used 
for chemiluminescence.

Our own application would involve quantitative footprinting sorts of 
experiments and thus both instruments have weak areas with respect to our 
ultimate needs.  I would be grateful if some users could comment on these two 
issues:

1) Accuracy of Quantitation
2) Resolution of the phosphorimager

Thank you.


Roland Saldanha