Best approach to images with high dynamic ranges, methoids

[mmirot]

I am having trouble with stretching a deep exposure of M27 do to its dynamic range.

Anything I do tends to blow out the the highlights if I try to bring out the faint outer shell. 

Using masks to protect the highlights is a problem for me. I tend to get artifacts as I stretch the image.

I can make several images with different MTF stretch settings that are optimal .
For example, a small  MTF to show the central hour glass with one clone and larger MTF on separate clone to show the outer halo.

If I do this is there a Pixel Math method to replace the blow out highlights on the larger MTF stretch with the small MTF stretch for the hour glass area. ?

Or is there another way to protect the brighter areas of the images?

Thanks

Max

[pfile]

what happens if you let them blow out and then use HDRMultiscaleTransform? if the 'blown out' areas are not actually clipped, this might work.

rob

[chrisvdberge]

Two things I can think of right away:
Did you try to mask and stretch step by step? It can be tedious, but prevents the artifacts you mention. (so mask, stretch, create new mask, stretch etc.)

Secondly, the faint outer shell might be in a very specific part of the curve. For instance, the way I highlight galactic cirrus is by adapting the curve in such a way that there is a little bump roughly at 1/4th on the lower part.

[mmirot]

Results are not really the best with HDRmulti.

Max

[msmythers]

Max

You might look at the ExponentialTransformation tool. Here is a simple example. I applied the CIE L* component as an inverted lightness mask to my Orion image. I then used the  ExponentialTransformation tool. I am pushing the image with these settings but the stars and the bright areas of Orion are still under control.


Mike