For the first year after I started working with Star Trail photography, I’ve used StarStax to blend my individual frames together into the trail photo. Unfortunately, StarStax has some limitations, and I have suspected that the resulting star trail image wasn’t as high of quality as the input images. So I started researching other options, including stacking manually in Photoshop. The root of the idea is to set each of your layers above the bottom layer to blending mode = ‘lighten’ – so the bright starts shine through on each subsequent layer. The problem is, when you have 200+ layers, that can take a long time to go through each photo and update the blending mode on each. Knowing that there were plenty of smart photographers out there and that Photoshop had multiple ways to extend and enhance with actions, panels, scripts, and the like, I knew there had to be automated ways to do this. The real question became, how much work would it take to reduce the amount of work.
I found several panels and the like that worked in CS5 or CS6, but not the latest Photoshop CC which I am a subscriber to. But fear not! Photoshop made it amazingly simple to set all those annoying layers to the same blend mode without needing a script, an action, or anything. It’s right there in Photoshop CC for the finding. If you know where to look.
First, load all your base images into Photoshop into a single stack (File -> Script >- Load Images into Stack from Photoshop, load from Bridge, or Lightroom, etc).
Second, scroll to the bottom of your stack and select the second to the bottom layer – the first layer you want to set to Lighten, and set the blend mode.
Next, Right-Click on your newly set ‘Lighten’ layer, a context menu will open up and scroll up and find ‘Copy Layer Style’
Select all the remaining Layers above your current lighten layer – all those annoying 200+ layers you want to quickly blend together.
Now for the magic, right click again on your selected layers and find that menu item that says ‘Paste Layer Style’ – try not to fall out of your chair at this point.
I just ran a stack of 200+ layers, results were near instantaneous. The star trail appeared within a blink of an eye (example below was done with around 70 frames)
As I’m only beginning to explore this new blending technique, I’ll update and add to this post, or add subsequent posts in the future as I refine and improve my in Photoshop star trail stacking.