How to Process Milky Way Photos

The Milky Way is one of the most awe-inspiring sights you’ll ever photograph, but it can be tricky to post-process the RAW images into something that truly captures the experience. In this tutorial, you’ll learn how to use RAW processing and luminosity masks to create gorgeous night skies. Be sure to see the list below with several more tutorials to help improve your night sky images using Photoshop and Lumenzia.

Key steps for making the Milky Way pop in your images:

  • Proper white balance in RAW. The colors are subtle and can easily get lost if you don’t spend the time to get the right balance.
  • Use the camera calibration tab to boost color.
  • Lighten the Milky Way using something like a +brightness adjustment revealed through a lights luminosity mask. In Lumenzia: create the adjustment, alt/option-click mask for a black mask, then L for a lights preview, slide or customize if needed, “Sel” to convert the preview into a selection, and then paint white through the selection onto the mask to brighten the light parts of the Milky Way.
  • Darken the surrounding sky using something like a -brightness adjustment revealed through a darks luminosity mask.

Other related tutorials for shooting and editing images of the night sky:

Lumenzia LITE: free luminosity masking panel for Photoshop

I’m happy to announce the release of a FREE luminosity masking panel for Photoshop: Lumenzia LITE. This panel allows you to quickly create 16-bit luminosity masks, channels, and selections. It’s completely new and a major improvement over my previous free panel (including native support for Apple Silicon / M1). In the video below, you’ll learn how the LITE panel works, how you can use it to create some gorgeous images, and some of the ways it differs from the full version of Lumenzia. You can download and install anytime via the footer of this and future newsletters.

Learn more about Lumenzia LITE here (including how it compares to the premium version of Lumenzia).

What’s new in Web Sharp Pro v3.7?

Web Sharp Pro makes it quick and easy to create gorgeous exports of your images for sharing. It offers much more than just sharpening, with custom templates, blurred borders, custom watermarks, advanced crops, film grain, batch processing, and much more. The best way to understand it is with the short demonstration below, and you can also learn more about the rest of its extensive capabilities here.

Web Sharp Pro v3 has advanced steadily with a series of free updates since its release last year and now v3.7 builds on these great features with secondary borders (under Settings / Quick Export), webP exports, and more. See the release notes for details on the 137 new features, updates, and bug fixes that have come out just since Photoshop 2022 was released in October.

Get Web Sharp Pro here.

Exporting webP files from Photoshop

Photoshop v23.2 just added support for a new file format: webP. In this tutorial, you’ll learn what webP is, why you should consider using it, and how you can easily take advantage of it with Web Sharp Pro.

What is webP and when should you use it?

The webP format is an open standard licensed for free from Google. It is designed to offer smaller file sizes on the web at similar or higher quality. Unlike JPG, it offers a completely lossless format to completely avoid any artifacts (albeit with a larger file size than a high-quality JPG). And unlike JPG, it offers support for transparency, which is critical when you want to allow the background to show around your subject (such as a product being sold on a website). If you’ve been exporting images as PNG to support transparency, webP offers massive reductions in file size (about 30% smaller lossless and >80% when saving in a lossy format comparable with high quality).

It is worth noting that there is an important difference between the lossless format and 100% quality lossy. Very small areas of color detail (such as a red light in a cityscape) may look significantly desatured compared to the lossless version. In general, you’ll probably need to look extremely close to notice the difference, but high-frequency color is one use case where I think the extra size of the lossless format may make sense. I don’t know if this behavior is inherent to the webP format or Adobe’s implementation of it, but I’ve seen differences in several test images. Aside from this narrow difference, I generally find the high-quality lossy version would look identical to the lossless version for most viewers at a normal viewing distance. You only see the differences when you’re pixel peeping pretty closely. And keep in mind that all JPGs are lossy, so we’ve been dealing with this for a long time.

This file format has already been around for a decade, so there is already widespread support including every major browser (Internet Explorer does not support it, but IE will be discontinued in June). So webP is an outstanding choice for sharing images on your website when you need transparency, and also offers useful file size reduction compared to JPG. This is a great way to improve page load times and save bandwidth costs for your website.

In addition to use on websites, webP is a great way to send smaller files for email or otherwise sharing with others. MacOS has native support via its image preview software and there are free tools for Windows. However, as that may require installing or configuring for support on Windows, I probably wouldn’t use webP to email everyone in your list just yet. However, this can be a nice way to hold down the size of your email account, save on wireless data costs, and send images over slow connections. Support for this standard keeps growing, and I expect we’ll see more and more JPG usage migrate to webP over time.

The latest version of Adobe Bridge supports webP, but Lightroom does not at this time. However, as this is a format for export, that shouldn’t matter unless you manage a set of pre-prepared images to share on demand.

This leaves the question of when you should keep using JPG or PNG:

  • Keep using JPG whenever you just want to know something will work. No need to test if you can upload to social media (though sites like Facebook support it) or know if your friend’s computer will be able to open the image. The file size savings are nice, but probably not worth a lot of hassle for most people.
  • Keep using JPG if you see a loss of saturation/detail in small vibrant colors, such as vibrant city lights at night. You can use the lossless webP format to avoid the issue, but the resulting file is larger than a JPG. Using 100% quality with webP will not prevent the issue, all lossy values are at risk. This is unlikely to the vast majority of images (especially when viewed at a normal distance), but it is an edge case to keep in mind. If you can’t see any image at 100%, it’s safe to use even if you can see something when you pixel peep further.
  • Keep using PNG when if you run into the extremely rare scenario where there is visible banding in your output and you need 16-bits to avoid it. You pay a large size penalty for this, but there may be times when it is worth it. Don’t do it because 16-bits sounds good (while 16-bits is critical in your source and working files, it rarely makes a difference for a finished image).

My quick summary would be:

  • Use webP when you have transparency. Even the lossless format is much smaller than PNG and JPG doesn’t work with transparency.
  • Use JPG if you don’t care about optimizing file size and bandwidth or don’t want to have to think about edge cases (with high-frequency color or recipients who may not be able to handle webP). This is the simplest solution for uploading to social media or emailing images to people with an unknown ability to handle webP.
  • Use webP when you want to optimize for fast transfer sizes and minimal storage, except potentially for a few rare cases where high-frequency color may be impacted (such as cityscapes at night). This is most beneficial when you’re hosting the images on your own website or trying to keep your email sizes down.


Exporting “webP” with Web Sharp Pro v3.7

Web Sharp Pro makes it quick and easy to create gorgeous exports of your images for sharing. It offers much more than just sharpening, with custom templates, blurred borders, custom watermarks, advanced crops, film grain, batch processing, and much more. The best way to understand it is with the short demonstration below.

Web Sharp Pro v3.7 just added a range of new features, including support for webP. See this quick demo below on how to take advantage of it. If you need to export an image with transparency, this is automatically handled for you. There’s nothing to do (other than checking that you aren’t adding a border, since that wouldn’t be very useful if you want transparent edges.

When exporting from Web Sharp Pro as webP:

  • “ultimate” quality setting will export with the lossless format. This will completely avoid any JPG artifacts, though the final file size will be somewhat larger than a JPG (about double the size). And it will be much smaller than a PNG (about a quarter of the size), though it does not offer 16-bits. This is a great option when quality is your priority and you have areas of very small color detail or want to completely avoid artifacts.
  • “high” is designed to offer quality comparable to similar settings for JPG, but with somewhat smaller final file sizes. This is a great option when quality is your priority. Differences from ultimate are generally very hard to detect without zooming in well past normal viewing sizes.
  • “good” is also designed to offer size savings over a comparable quality JPG. This is a great option when small files are your priority (and the loss of quality at this level will be minimal, usually very hard to detect).


Exporting “webP” directly from Photoshop

If you don’t use Web Sharp Pro, you can simply use File / Save a Copy in Photoshop and select webP. I recommend the following settings:

  • Always leave the option to embed the profile checked in the first dialog (before the webP options)
  • Lossless if you need an exact copy of your image. Otherwise 75-90% lossy is a great range to consider. As you get closer to 50%, there is a noticeable loss of quality, but it may not matter for your application and this can really shrink the file size.
  • Embed XMP if you want to keep keywords and other such non-camera data.
  • Embed EXIF if you want to keep camera data (shutter speed, lens, etc).
  • Embed extras if you want to keep paths, guides, and print settings.

Three ways to use mask DENSITY for more natural edits in Photoshop

Layer masks are the key to nearly all great images created with Photoshop. They let you make targeted adjustments, blend images, composite, work non-destructively, and are probably the most important component of using layers. Masks have two properties which are designed to help you get more natural-looking results. You may already be familiar with mask feathering, which allows you to soften the edges of your mask for a more gradual result. But the other property, “density“, is one that I almost never see other photographers take advantage of. It’s incredibly useful in certain scenarios, but it isn’t obvious and most photographers never realize it can help improve their images.

We’ll cover several great ways you can use density, but it’s important to first understand what it actually does. Layer masks control the visibility of individual pixels of a layer (including images and adjustment layers). The basic principle is that as you paint on the layer mask: “black conceals”, “white reveals”, and gray gives some proportional results. There are times when it would be helpful to ensure a minimum visibility (gray) in the layer mask, and that’s what density does. At the default 100% density, the layer mask looks exactly as you painted it. But as you slide reduce density, the dark values in the mask are lightened. If you slide all the way to 0% density, the mask becomes pure white (even if you have true black in your mask)! Let’s explore a couple scenarios where you could benefit from adjusting density.

Using density for more natural-looking transitions

Filters often look best when you apply them in a targeted way that affects some parts of the image much more than others. For example,a noise reduction filter works best if you apply it more aggressively in smooth areas (such as sky and water) than in areas where you wish to retain detail. You can paint a layer mask that will help do that using white to cleanup the sky/water while using darker greys elsewhere to strike a balance of noise reduction and detail. Because you probably want at least some minimum effect everywhere in the image, the mask is going to have a minimal gray – and that’s exactly what density offers. So rather than spending too much time painting a very fancy mask, you can simply paint white on the sky/water areas that need the most smoothing. Then just adjust the mask density to reveal some noise reduction everywhere else. With minimal effort, you’ll get a perfect result with no obvious transition edges. It’s fully non-destructive, so you can readjust the density anytime you need.

You can use this approach when using a layer mask on an adjustment layer, such as for color grading or color overlays. Anytime you want the effect to show more in some places than others but need to show a little bit everywhere to look natural, density is a great solution. I show this in the video to improve a color overlay, which could just as easily been any form of color grading.

It works very well with smart filter masks, such as for sharpening and noise reduction. You could also use it to improve complex filters such as Nik Color Efex Pro or Luminar. Just apply a filter to your Smart Object, invert the filter mask to black, paint white where you need the filter most, then adjust the density to balance out the effect across the whole image. It’s the same workflow I showed in the video above to reduce noise.

One thing to keep in mind is that this control is separate from the master layer opacity, BlendIf, and vector masks. So even if you make the mask white via density, these other factors can still hide your pixels.


Using density to help blend a layer

Exposure blending, time blending, compositing and other forms of combining layers with different content typically involve painting white on a black layer mask to reveal each layer. Until you’ve revealed your subject, it can be hard to know exactly where you should brush on your image. In other words, you need a bit of a “sneak peak” to know how to paint the mask. You can <shift>-click the mask to disable it, but this reveals the layer entirely and obscures everything below it. Mask density offers a way to get something in-between to let you see everything at once. Just slide the density to around 50%. This will show the blend layer enough to know where to paint, while showing the underlying content at the same time. And as you paint, the blend layer will become more and more opaque so you still get a good sense of the blended result. Once you no longer need the visual aid, just slide density back to 100%. Be careful to slide all the way to 100%, so that you don’t allow unwanted portions of the layer to create unwanted ghosting.


Controlling density via Lumenzia

The sliders in Lumenzia allow you to not only adjust Lumenzia’s previews and BlendIf, but also the sliders for layer masks including feather and density. When you click on a mask to make it active, the precision slider in Lumenzia will show white to indicate that it is ready to adjust the feather on that layer or filter mask. To adjust density instead, just <alt/option>-click the slider and it will turn yellow to indicate that it is ready to adjust the density on that mask.

Greg Benz Photography