Help with HDR

[mcintyre_sj]

I want to combine three calibrated images of different exposures of M42 that were created from stacks from a DLSR.

The default HDR was ok, but i am not completely happy with the resutls. For one, the bright stars in some regions look like doughnuts as i can see three different sized disks stacked onto one another. Its not obvious with the linear combination, but when i stretch it, the problem shows up.

I would therefore like a little help with some of the parms for the HDR script:

1) I am not really sure what is meant by the highlight and lowlight parms? Since i have three images, what should i be looking at in the images to select parms other than the default. I know what regions of each image i what to include. (It's M42 so you your guess would be correct

2) The input files are too red so there is a huge descrepency between R and GB values for the pixels in the regions i want to include. So i am not sure how the highlight and lowlight will deal with this.

3) Since the main problem is the layered stars, will increasing the mask smoothness work, or do i need to also increase mask growth.


Thanks,
   Stephen

[mcintyre_sj]

I ran numereous tests with a crop of the three files being combined, and i still am not sure what hightlight and lowlight are doing and how changing the ranges helps. Fortunately, the defaults work ok.

I presume high and low define the area for which a transition is occuring, but i am not sure. And the range is the range of values along either the high or low boundary.

In order to determine what the values should be, should i be looking at the brightest image - longest exposure, or the fainter image?

All just guess work for me now so I would really appreciate it if someone could give me a few tips.