Processing Milky Way shots with Photoshop

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Lake Superior Milky Way
The Milky Way over Lake Superior's North Shore Photo by Gene Dianoski

As promised this article is processing Milky Way shots I took last month. I don’t profess to be a professional photographer or a professional Photoshop photo editor. Like most of the hobbyists out there, I’ve done a lot of internet homework on the subject. This is just one of many processes and assumes you have more than a beginner’s knowledge of Adobe Photoshop CC.

The image was taken with a Canon EOS 80D and a EF-S10-22mm f/3.5-4.5 USM lens. The lens was opened all the way to 10mm and the camera set to f/4.5 at ISO 6400 for a 30 second exposure. There is a lot of digital noise in this image that I don’t quite yet know how to reduce in camera yet. That’s a goal to work on.

The Raw File
The Raw File.
Image by Gene Dianoski

Processing Milky Way shots in Adobe Camera Raw

To start the editing process in Adobe Camera Raw I like the color Profile of Adobe Landscape and adjust the Temperature down a little to where looks good. Somewhere around 3700 looks nice. I bumped up the exposure to +50. Like most of my editing work, I moved the Highlights all the way down to -100, but instead of opening the Shadows all the way I just bumped it up slightly to +19 and upped the Whites until it looked okay.

Adobe Camera Raw settings.
Adobe Camera Raw settings.
Screen clip by Gene Dianoski

Adjusting some of the Noise Reduction sliders in Adobe Camera Raw is also a good idea but be careful not to over do it. Moving some of those sliders past 50 or 60 can make the image look worse than the noise. Once done here open the image in Adobe Photoshop CC.

Adobe Camera Raw Noise Reduction settings.
Adobe Camera Raw Noise Reduction settings.
Screen clip by Gene Dianoski
Image after Adobe Camera Raw adjustments.
Image after Adobe Camera Raw adjustments.
Image by Gene Dianoski

First curves adjustment layer in Photoshop CC

My first step for processing Milky Way shots is almost always to adjust the White Balance. I do it so often now I’ve created an action for it and after completing merge the two layers. The next step is creating contrast between the darkest and lightest areas of the Milky Way. Open a Curves adjustment layer and use the slider icon to find where on the curve those points lie. Move the light point up and the dark point down.

Contrast Curves Adjustment Layer.
Contrast Curves Adjustment Layer.
Screen clip by Gene Dianoski

This will make things look bad because of heavy contrast. Invert the layer mask and use a broad soft brush tool to paint in the Milky Way with white. Then, while keeping focus on the layer mask, apply a Gaussian Blur filter of something high like 255.  This Gaussian Blur filter will be used a few times in this process with the same setting of 255. Merge these layers and make a layer copy.

Image after Curves adjustment.
Image after Curves adjustment.
Image by Gene Dianoski

Unsharpen mask

On the copy layer, if needed, use the Unsharp Mask filter to sharpen the edges of the dark lanes in the Milky Way. Use Filter > Sharpen > Unsharp mask. Like on the Curves layer above, invert the mask and paint in white along the dark edges of the Milky Way. Then use the Gaussian Blur filter to smooth out the edges on the mask again.

Unsharp Mask filter.
Unsharp Mask filter.
Image by Gene Dianoski

Burn the dark paths

An alternative (or extra help sometimes) to the Unsharp mask is to just use the Burn tool to darken the paths of the Milky Way. This might take some experimenting to get it to look normal. Use a low flow and maybe adjust the exposure. I use a flow of 4 and I’ve learned it’s too easy to overwork it. This is one of the reasons I use a layer copy here. If you get too heavy handed you can decrease the layer opacity to dial it back incrementally.

Burning in the dark paths of the Milky Way.
Burning in the dark paths of the Milky Way.
Image by Gene Dianoski

Color adjustments with curves adjustment layers

Now I go back to using Curves Adjustment layers to adjust the colors. In the dropdown box where it defaults to RGB click down and pick any of the colors and adjust color as you see fit. This will be highly subjective and never the same from image to image. I worked to take some of the green and reds from the light pollution areas using the mask to return some green back into the Milky Way where I liked it.

Making color adjustments with a curves layer.
Making color adjustments with a curves layer.
Image by Gene Dianoski
Image after color adjustments.
Image after color adjustments.
Image by Gene Dianoski

More noise reduction using Nik collection define and luminosity masks

The knowledge and use of Luminosity Masks can really help in finer adjustments for processing Milky Way shots. I did further noise reduction in the image using the Nik Collection Define noise reduction filter and applied a brights 1 luminosity mask to keep the edges of the brightest stars sharp.

More noise reduction using Nik Collection and a luminosity mask.
More noise reduction using Nik Collection and a luminosity mask.
Image by Gene Dianoski

At this point I think there is still too much red and green in my image so I’m going to adjust them again using the same steps as above. At this point it’s small subtle changes.

More color fixes using curves layers.
More color fixes using curves layers.
Image by Gene Dianoski

Finishing touches

To finish up the image I used dark 6 Luminosity Mask on a Curves adjustment layer to darken the darkest areas of the image. I also used the Dodge tool to ever so subtly up the brightest areas of the image I thought could use it. Here’s the final image using these steps for processing Milky Way shots.

Final edit for processing Milky Way.
Final edit.
Image by Gene Dianoski

I hope this article helps some of you hobbyists out there for processing Milky Way shots. If you have other ways of editing your astrophotography images, please share them in comments below. Also, if you have questions or want finer detail on aspects of my process let me know that in the comments below too. Now go forth and photograph the night sky!

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