Histogram Stretch - How Far?

[ianaiken]

Hi all,

Finally got some data this season to complete an image!  Yay for me! 

Right... so I've been processing the Ha data and trying to come up with the right balance of stretching the image to show the faint stuff without making some of the brighter parts too bright.  This is something I picked up from Olly when he kindly processed an image of IC1396 I took.  However I am struggling a bit with good methods in PI to do this or more so control all of this.  I always tend to have too much contrast and too bright.  Maybe it's a simple case of backing off on processing but then I want to make sure all the faint stuff is visible.

I've got two revisions here.  One I think the Bubble is a bit bright and the other is a bit flat.  Any tips or suggestions or processes or scripts or tutorials?

V1

V2

[ianaiken]

Actually it looks a bit better mixed with the RGB data but I think I've lost a bit detail in the bubble itself through stretching.

HaRGB

RGB

[ianaiken]

I guess it's down to personal taste really I just wanted to avoid losing details and not ruining an image with over processing.

[ollypenrice]

Can't help with PI but in PS I handle high dynamic range by using layers. I blend saturated with unsaturated layers to get the best of both worlds. Then I'll noise reduce only the fainter stuff. I like Ps simply because I can see what I'm doing with this process as I'm doing it.

Olly

[ianaiken]

Hi Olly thanks for the reply.  in PI I found a process called GradientHDRCompression and it helps to bring out the fainter stuff.  Using masks I can control some of the brigher areas.  I agree PS is easier to use but I am finding PI to be much more powerful once you do get your head around how it works.

Here's the Ha using the GradientHDRCompression.  I'm going to have a go in PS now with your suggestion and merging the layers.  I know this data has much more to come out of it.