DSLR colour is all wierd

[Kaptain Klevtsov]

This is supposed to be M31, but the colour has gone all wrong and I can't figure out a)why, or b)how to fix it.

All tips appreciated

Captain Chaos

[moondog]

CC How was it shot and processed ?

Back ground looks very odd with the mottled colours.

Also the star colours look as if the white point in the image wants adjusting.

MD

[Kaptain Klevtsov]

10 frames stacked in Registax.

ISO1600, 90 seconds per frame.

Nikon D50 with CLS filter on a Celestron 80mm f/5 Achro.

Colour balance has not been played with on this stack as I have played and failed, so this is straight out of the box.

The black point was adjusted with the dropper tool in levels, but doing a white point made the galaxy bit very gaudy and red.

Captain Chaos

[moondog]

CC

Don't know what went wrong but it could be Registax. I'd been having some weird effects with it for stacking etc. This is why I changed to ImagesPlus.

I've pulled your image into PS Elements and lowered the Cyan colour in the stars and slightly darkened and smoothed the background. Don't know if you think it's an improvement or not !

[moondog]

CC

Sorry clicked wrong button - here's the image.

MD

[Kaptain Klevtsov]

That looks the business MD. The big image has the bottom missing though for some reason. Thanks for that.

Captain Chaos

EDIT Now the picture's all there.

[MartinB]

CC, here's how to make baseline adjustments for colour in photoshop. use the histogram tool to show the histograms for the 3 colours. There are 2 problems - colour bias and colour balance. Colour bias shows itself as a coloured background and shows up as different blackpoints in the 3 colour channels. Make sure the black point is up against the left hand edge of the histogram in all 3 channels. Readjust this every time you make a change with curves. Colour balance is where the white points aren't consistent. This is adjusted by the colour balance tool. Use the sliders with reference to the histograms so that they are positioned similarly in all 3 channels. That should sort out most basic problems. You can fine tune using shadows and highlights along with tweaking curves in individual channels

[Kaptain Klevtsov]

Thanks Martin, I'll give that a whirl ASAP.

Captain Chaos