Paul, you got a photo well done.
Not a guru mate, I dare say the blue is in the processing when using colours etc. I use pixinsight but when I did use PS Ideally remove stars and work on the photo without them. You can shrink the stars using levels and sharpen with smart sharpen. You can then use hue saturation on the stars for better colours. Also put the photos in their own group so its not destructive. For a more natural colour try to keep colours around 20 ish.. the colour sampler tool is useful there..from memory.
|