How to submit and measure images with a clear or luminance filter?

Hi!

For time series, it might be good to use a clear or luminance filter rather than V - that's what I've recently learened - as we are more interested in the variations than the magnitued. 

So how then do I go about uploading and using a Lum filter, for instance? I've tried and find that in the measurements window, It is noted that the image is not taken with a photometric filter, and I can choose what to use as reference and what to report as. However, setting V and C (measuring with V band and reporting as C) still gives me just 0.000 as magnitude. So how should I do this?

Magnus