> Pedro J Camello wrote:
>
>...........................................................................
..The emitted
>fluorescence is enough for our camera but the relative changes in
>F340 and F380 are extremely small, so that the ratio has a very poor
>signal to noise ratio.
.................................................................

Is it possible that your 340nm image is weak while your 380nm image is
adequate? If so your optics may not be transmitting enough 340nm light. Do
you have a good UV transmitting lens and condenser? If the 340nm signal  is
a little too weak you could try using 350nm instead of 340nm, so that you
obtain better transmission through your optics.

Cheers,

Stephen H. Cody,
Colon Molecular and Cell Biology Laboratory,
Ludwig Institute for Cancer Research,
Post Office Royal Melbourne Hospital,
Parkville, Victoria 3055, Australia.

Tel: 61 3 9341 3150   Fax: 61 3 9341 3104
email: [log in to unmask]