In the previous post we looked at a number of images taken straight from the camera. With exposures of 20-30 seconds and high ISO settings these photos are very ‘noisy’ and have green-brown colour casts that are not that attractive. Processing the images in software such as Adobe Lightroom it is possible to remove some of this noise and highlight the night sky using blacks, blues and magenta to create some quite spectacular night skies. Using editing software it is also possible for the photographer to create the images the way they imagine them when taking the photos so it is possible to be quite artistic. When processing the images from the photoshoot I played with a number of settings in lightroom but essentially tried to emphasise the whites, remove the brownish tinge and highlight blues and magentas. Below is an example of before and after processing.
The images below show more clearly the settings that I have used. Each photo will be different and settings should be adjusted to how you envisaged your image. I have reduced the ‘temperature’ of the image to make it more blue and increased the tint away from green towards magenta o try to remove the green-brown colour cast of the original. In order to bring out the stars I played with the highlights, shadows, whites and blacks settings until I found a combination that I liked. The colours were really quite bright so I reduced the vibrance a little. My personal preference would have been to reduce it further however what I wanted to do was illustrate quite vividly what is possible in post-processing. The image on the right shows the noise reduction settings. Setting the luminance reduction so high resulted in many stars disappearing however I don’t mind that as the result is that it draws more attention to the main star cluster (the Milky way) which is what I want to feature. The other processing that was performed was to add a vignette (darken the corners). This gives the picture a bit more drama but also helped to remove some of the chromatic aberration around the trees which I couldn’t get rid of.
Towards the bottom of the horizon you can see some discolouration in the sky. This is the light from pre-dawn. Most of the photos were taken between about 3am and 4.45am in the morning as the moon was in the sky until very late in the night. As it got closer to dawn this became more prominent but actually looks quite good in some photos. The next post will feature a gallery of processed photos.
As indicated, most image processing software (from free to quite expensive) will support the types of adjustments mentioned in this post. See what you can do with the unprocessed images from the previous post or from your own images. If you would like to share your efforts please post a link in the comments below to your images.
If you have any ideas on how you process long exposures of night skies and would like to share them, please leave a comment – I will be happy to have some feedback.