How to increase red nebulosity colour with Photoshop?

[Mr Bergman]

Hi all,

I have a 30 mins worth of Rosette with an unmodded DSLR. The nebula is seen clearly, but how do I increase the nebulosity´s colour without destroying my stars, or without making the picture look artificial? I heard about switching to LAB and making the curves steeper in A+B channels, but that also affects my stars.... Should I use a starmask? Best way of doing that? Or do you have any other tips or tricks? OR should I just go for more exposures, maybe an hour or two?

Any help is welcome!

Have a nice day!

[Jannis]

The best is probably to create a star layer first, yes.

[ollypenrice]

One ridiculously simple technique is to go into Image, Adjustments, Selective Colour and, when it opens, push the top slider in Reds over to the left in the Cyan balance. It will (probably) blow you away! It has little effect on star colour but enhances the Ha signal from broadband red. Sometiles the result is beyond belief.

The Lab technique that you mention is excellent as well. If you like the effect on the neb but not the stars just select the stars (Martin B's tutorials on here or Noels Actions) and reduce saturation afterwards.

The best way to enhance the Rosette is with a dedicated H alpha layer.

http://ollypenrice.s... FIN3WEB-X3.jpg

Olly

[RikM]

That selective colour tweak is staggeringly effective. Thanks for that one Olly

I normally work on a curves layer set to 'red' and try and boost the interesting bits while keeping the other bits under control.

[laser_jock99]

If your software can split an image into three colour channels, it is possible to 'play' with the red chanel data completely separately & then re-combine the three channels into a new image.