Flats not working for some reason

[blinky]

I took flats as per normal after my 4hr run on M33, I stacked in DSS but it appears to have made everything worse! Vignetting is now terrible and the dust bunnies seem to have expanded! I cant for the life of me think what I did wrong...... All I can think of is the flats are somehow wrong, but I used the script in MaximDL create them along with my custom light box which has worked fine in the past.

Here is an image from Photoshop, left is the stacked and slightly stretched image with the flats applied, next is an image of the flats, again stretched to show the dust etc is in the same place, and at the right hand side is a version stacked without the flats at all, I think you can see it's better than the one with the flats!

[Spikey]

Looks almost as if the flats have been stacked with the image and not subtracted.

[blinky]

Now.... I did just quickly drop everything into DSS, I wonder if in my pre-coffee state this morning I added the flats as lights as well????

[blinky]

No, its not that, just checked and it has actually created a master flat so they were not set as lights - I dont understand whats gone wrong!

[RobH]

Did you bias subtract your flats?

Rob