Star Stacking: Combining Layers With Lighten Blending Mode
What I like to do is break up my star stacks, rather than using one long exposure of 20 or 30 minutes. I like to break up into individual exposures, so if we click on any one of these, we'll see that this is 150 seconds, so just a little over, it's about 2 1/2 minutes at 5.6 at ISO 100, and the reason that it's so short, and you may not think 2 1/2 minutes is short, but compared to a 20 or 30 minute exposure it's quite short, the reason it's so short is because this is a full moon. So if I was to go in on this image and look at it, you could see all this illumination is just natural full moon light, and what we're seeing here is just a little bit of star movement. If I zoom in you can see just a tiny little bit of star movement, but if I go to my next image, you see the stars moving, and moving, and moving, and if I do enough of these, it will actually turn into a nice little ring, 'cause I'm pointed due north. All right, so first steps first. What we're going to do is ensure that we a...
re actually adjusting the image the way we want it. So here is the image straight out of the camera, and it didn't feel quite like it had the snap that I wanted it to. So what I actually did was adjusted it to this and we can go in and look at my adjustments. It's nothing too terribly intricate here. This is pretty much straight out of the camera, so what I'm gonna do is I'm gonna again, change my white balance if I see fit. This is shot at 4900, so I'm gonna bring it a little bit more towards blue, and actually, I think I'm gonna warm it up a little bit. Yeah, I'm gonna go up to about or about 5500, which is pretty close to daylight. I'm also gonna bring up my shadow value a little bit, not too terribly much, but I do want to get some detail in here, and I could even go into my clarity and bring that up a touch, and maybe even some dehaze, and dehaze is gonna start to separate that sky out from the stars a little bit better by adding some dehaze. Be careful though, kid gloves with this tool. You don't want to go too much. It gets fake really quick. All right, now what I'm gonna do is go down to my HSL, and I'm gonna go into the saturation of the oranges by clicking on saturation and then using this direct selector tool, and just click in that orange and lift it up, and that's gonna increase that orange saturation a little bit as you can see over here. So I'm just clicking and then lifting my mouse up, and that's automatically moving the sliders here. So what I did was I went around and I made some changes in this image, and then once I do that, I'm gonna need to sync that with all of these photographs in here. So you'll notice this is the brightest one. That's the active image, these are the dimmer ones, and they're selected but not active. So when I'm in the develop module and I hit this sync button, right here, it will sync all those settings across each and every image. All right, so I hit sync and it says what would you like to synchronize? And I say well, I would like to syncronize everything, thank you very much. I'm gonna hit check all and then synchronize, and it's finished up. Now, for the sake of spending less time here watching my computer just process, what I've done is I've turned all of these images into the actual JPEGs, so these JPEGs here are all ready to go, they've been processed, much like the way I just showed you, and now we're ready to bring them into Photoshop. Now, a couple of things I want to point out. As I had mentioned, I could just let this exposure run for you know, 15, 20, 30 minutes, an hour, two hours, or even longer if I wanted to, but what I was able to do is paint in different amounts for each photograph. So for example, here is the first photograph that I took. And you can see I really didn't light paint the tree. The next one I lit it a little bit, the next one a little bit more, next one a slightly different area. This one no light painting, no light painting, no light painting, and on and on. And so if I've made a mistake during any one of these light painting exposures, I can go out and erase that from that individual frame. This adds a lot of flexibility into star stacking. If I let my shutter go for 20 minutes and I went in and I light painted and I did a poor job, I wouldn't find out until 25 or 30 minutes later and I'd have to start the whole thing over again. So that's the thing that I like most about light painting with individual shorter exposures and then blending them all together. All right, so we are ready to go. I've selected all the images, and once again, I would actually normally do this with the RAW files, but saving a little time here I'm gonna use JPEGs. And we are just simply gonna go up to photo, edit in, and open as layers in Photoshop, and that will launch all of those photographs. It'll create copies. If they were RAW it would create a TIFF copy, and it's gonna send them all into one big file inside of Photoshop, and as you can see, it's going to take a little while to do so, even though they are actually small kind of JPEGs. Okay, it looks like it's just about ready here. Let's see what we've got. All right, I'm gonna double click on this word, properties, so that it collapses that frame, and you can see we've got all of our different layers in here ready to go. Now, this is the easiest thing that we can accomplish in Photoshop, I promise you. There's so many complex techniques. This is not one of them. All I have to do is click on the top layer, go all the way to the bottom, hold down my Shift key, click on the bottom layer. That selects all of these layers, and then I just simply go up to this word, normal, and this is the blending mode options, and I'm gonna choose lighten, and as soon as I choose lighten you will see all of the star trails created. And the reason that that's doing that is simply because whatever is lightest under each one of these is gonna come all the way to the top of the frame so we're gonna be able to see the brightest parts of this bottom frame, and the brightest parts of this frame, and the brightest parts of this frame, and that creates that star trail effect. Now, some people don't like these simply because you do end up with these tiny, tiny little gaps, and there's real purists out there that don't like these gaps, and you wouldn't see those gaps if we were doing one long exposure of say 20 minutes. So if you don't like those little gaps in your image, then you're probably gonna want to use the long exposure. But I would say look at it at 100% magnification, which you can get to by hitting command one, and those gaps aren't real obvious, but pixel peepers will certainly alert you to the fact that they're present. All right, now in this case, I feel that my light painting actually did work, so I light painted one or two, I think it was actually three different layers or individual exposures, and I think it comes out pretty nicely, I'm liking it. But if I didn't want to, what I could do is I could go onto any one of those layers that had the light painting on them, and I'm just looking for them by clicking on and off my eyeballs here. And I'm not seeing any of them. There we go, so there's one right there. And the other thing is is that you could also notice that if you're looking up in your sky, you would actually get a fairly serious gap if you removed those other layers. So we can't take one of those layers out. We can't take one of those exposures out, or else it'll ruin the flow of the star trail. Now you could lose one end or the other end, but you can't take one out of the middle. So if for some reason I didn't like the light painting in one of these images, I could go to that particular layer. I wouldn't want to take it out, but what I could do would be to change up the amount of that tree that's showing through by throwing a mask onto that layer and then painting out the areas that I didn't like by using a black paintbrush.