Welcome to The Light of Night’s first post-processing blog! If you’re new here, The Light of Night is dedicated to creating post-processing tutorials. In astrophotography, post-processing is half the battle to being successful in creating some stunning astrophotography, so I’m here to show you what I’ve learned in a step-by-step blog. Before we jump in, the main programs I use to process my astrophotography are Adobe Bridge, Adobe Camera Raw, and Adobe Photoshop. I’ve originally started with Lightroom as my main processing software, but as I’ve grown in my experience, Photoshop has become an incredible tool that has taken my astrophotography to another level.
Step 1: Sorting and Culling
This step is SO important and (admittedly) one that I haven’t always been good at. Even with my portrait and product photography, importing, sorting, culling, and backing up files has been my least favorite step in post-processing and one, learned through the hard way, is ESSENTIAL. My individual workflow has something that I’ve developed over the last year and it may not be what makes sense to you, but here’s my importing, sorting, culling, and backing up process that I currently use.
One of the hardest lessons I’ve had to learn is that backing up your files are so important. I don’t care who you are, some way or another your files can/may become corrupt, lost, or mislabeled, so backing up those files somewhere other than your computer is key. I currently have four places where I back up my files: my computer hard drive, an external hard drive, via Google Drive, and Microsoft’s OneDrive cloud storage. I have SO many files, so there’s a possibility that you’ll need to purchase more cloud space and external drives as you shoot more.
Once I have my files backed up in the usual four places, I then start importing those RAW files into Adobe Bridge. Adobe Bridge is an awesome tool and one of the programs that comes with the Adobe Creative Cloud subscription. Once my files have successfully imported I get to sorting and culling.
I start by rating my images by what I think they’ll be capable of looking once I’ve started post-processing.
My highest rated images (5-stars) are ones that I got exactly right in-camera and a 4-star rate are images, that with minimal editing, I can get to that high-quality image I want and are portfolio ready. 3-starred images are images that are mediocre and I know require a lot of post-processing work on my part. 1-2 star images are regular snapshots that I rarely even work on. To rate my images, I use these shortcuts:
Cmd (Cntrl) + 5 = 5 stars
Cmd (Cntrl) + 4 = 4 stars
Cmd (Cntrl) + 3 = 3 stars
Cmd (Cntrl) + 2 = 2 stars
Cmd (Cntrl) + 1 = 1 stars
After rating my files, I then filter the files I rated. I typically only filter through the 4 and 5-star images–and depending on how many photos I’ll need–I’ll add in my 3-star rated files. Once those are filtered I then flag the top picks–images that I’ll actually process.
Step 2: Processing
Now we finally get to the fun part: editing! The sky in your files are 10/10 times going to look uninteresting and dingy, so that’s where processing comes into play. Even though you can do a lot with editing software, getting the exposure correct in-camera is ESSENTIAL. No over-processing will compensate for the lack of work you have to put into getting the exposure right the first time.
First things first: Exposure
Once I have my final picks in Bridge, I choose my first image I want to process and double-click it. By doing that, two programs are automatically opened: Adobe Camera Raw (ACR) and Adobe Photoshop. If you have Photoshop downloaded you’ll already have ACR as the automatic companion to the Photoshop software. Here the software dialogue will be similar to the Adobe Lightroom interface. You can adjust exposure, contrast, and parts of the file histogram (highlights, whites, shadows, and blacks), color (HSL), and other correcting adjustments. With ACR I only focus on bringing out the highlights/whites, darkening the shadows/blacks, and adding clarity to my image. All color processing will be done in Photoshop.
Depending on my image, I’ll have to adjust the highlights and whites. I usually keep that anywhere around 40-60 on the highlight slider and around 35 for the whites.
Here’s the RAW image side-by-side of the before and after adjusting the highlights, whites, black, shadows, and clarity:
After I got my desired exposure in ACR, I’ll click the ‘Open Image’ button at the bottom. From there, this will open the RAW file in Adobe Photoshop.
Step 3: Adobe Photoshop
We’re finally in Photoshop! With my background layer selected, I’ll duplicate it by using the keyboard shortcut (Cmd+J). By doing this you’ll have a foundation for non-destructive editing. If you don’t end up liking your edits, having this duplicated background layer ensures that if it were to be deleted, you’ll have that original RAW file to use without destruction of pixels.
Curves Adjustment Layers:
I begin my edits in Photoshop by adjusting the hues and saturation of the photo. I first select a curves adjustment layer. Under the RGB drop down menu, there’ll be several color channels–red, green, blue–for you to choose to edit. I start by editing the reds and greens, and will add an additional curves adjustment layer specifically for the blue channel.
In each color to edit I make sure to pay attention to the channel and how it’ll affect the hues of the specific image. Raising the red channel will add more red to the image while dropping the curve will add blue to the image. Raising the point above the curve will add that color to the image (according to the tonal area you’re raising) and dropping the point below the curve will do the inverse. I like to create color contrast (Milky Way vs. the rest of the sky). The milky way I’ll add and adjust the color to be vibrant. For the rest of the sky I like to keep it more of a navy blue/dark blue hue. Using color contrast I keep the milky way the focal point while creating the sky as the background.
Here’s the image with the red, green, and blue channels adjusted:
Hue/Saturation Adjustment Layer:
The next type of adjustment layers I use are hue/saturation adjustment layers. This is another tool in Photoshop where you can adjust the hue, saturation, and lightness of the colors. Within the hue/saturation dialogue you have the option of targeting certain colors without affecting the rest. Here is where I isolate the different colors within the milky way and pull out those rich colors my camera was able to capture.
Similar to the curves adjustment layer, I create 2-3 of these layers. The first usually being where I adjust the reds and yellows, the second being magentas and cyans, and lastly the blues have their own adjustment layer. Because of the white balance I use, most of the color in the sky is blue, so one layer dedicated to blue in case I need to use the layer mask to paint in the areas where I want that blue specifically while keeping the rich colors of the milky way. The amount and what colors I target will vary, but with this image, it’s predominantly blue, so I’ll have several layers where I specifically edit the blues with layer masks.
Here in this image I started my first blue hue/saturation layer by paying attention to the milky way and making it more purple. With the adjustment applied to the whole image I hit Cmd+I on the layer mask and select a soft, low opacity (30-40%) brush with the foreground color set to white. Then I start painting in where the milky way is and adding that rich purple color. With the milky way adjusted, I add another blue hue/saturation layer and start to pay attention to the rest of the sky. I like to keep it natural, so more of a navy blue and dark blue color. Here’s the image so far:
With the coloring where I want it, I go toward adjusting the white/highlights for one last time before I do clone stamping, last corrections, and sharpening.
With all of my adjustment layers in order I create an merged all layer. Essentially it creates a layer that collects all of the layer information into one layer. This will allow me to apply the Camera Raw Filter, clone stamping, and sharpening. The shortcut is Shift+Opt+Cmd+E.
Step 4: Last Corrections
Like I said in the previous paragraph, I’ll go ahead to the top menus and under Filter>Camera Raw Filter. This will bring back the ACR sliders to finalize the exposure.
Once I have the exposure sliders to the point that I want them at, I’ll hit ok at the bottom. I’ll then duplicate the layer with Cmd+J and start clone stamping out distracting parts of the image. In this case, the bottom light trail from a dune buggy is distracting, so I’ll clone stamp that out. The keyboard shortcut to that is S.
After you’re finished with clone stamping hit Cmd+J to duplicate that clone stamp layer. The image is finally ready for the last step: sharpening. I cannot emphasize enough how important sharpening is. Whether you’re preparing your image for digital purposes and especially print, sharpening is REALLY CRUCIAL. For printing purposes, not sharpening will have you end up with blurry parts of the sky that you’re not intending. Even if you end up exporting this to post online, sharpening makes such a difference.
With that top layer selected I sharpen the image by going to Filter>Sharpen> and either Smart Sharpen or Unsharp Mask. Unsharp Mask is a lot easier and more intuitive to use, so for this tutorial, I’ll use Unsharp Mask.
In the unsharp mask dialogue you’ll have a zoomed in portion of your image, previewing how the amount of sharpening will do to your image. I generally like to keep the radius between 2.5-3 with sharpening anywhere between 90 and 120. By unchecking and checking the preview box, you’ll also see before and after versions of the sharpening applied to the image.
Here’s the final image!
If you have any questions about any parts of this blog tutorial, feel free to check out my contact page here on my website! I’d love to talk to ya. Thanks for stopping by and reading this this tutorial on how to process the night sky.
Here’s to clear skies!!