Create A Starry Sky In Photoshop

Step 9: Add A Levels Adjustment Layer

We're going to turn all that ugly noise into some stars at this point, and we're going to do that using a Levels adjustment. Now we could use a regular Levels adjustment by going up to the Image menu at the top of the screen, choosing Adjustments, and then choosing Levels, but we don't want to do that. In fact, we almost never want to do that. And when I say "almost", I mean never, as in we never, never want to do that.

The reason is because we would be making permanent changes to our image, and why make something permanent when you don't have to? Why not give yourself the freedom to go back anytime and make changes, without having to worry about harming the image in any way? You can give yourself that freedom in Photoshop by using Adjustment Layers, which are special layers that do the exact same thing as if we were to choose the adjustment from the Image menu, but without making any permanent changes to your image!

In this case, we're going to use a Levels Adjustment Layer. With your "Stars" layer still selected, hold down your Alt (Win) / Option (Mac) key and click on the New Adjustment Layer icon at the bottom of the Layers palette:

Then select Levels from the list of Adjustment Layers that appears:

By holding down "Alt/Option", this tells Photoshop to pop up the same New Layer dialog box we saw earlier before adding the adjustment layer. We're not going to use it to name the layer though like we did last time. This time, we want to select one of the other options in the dialog box. Directly below the "Name" option at the top, you'll find an option called Use Previous Layer As Clipping Mask. By selecting this option, any adjustments we make in the Levels dialog box will affect only the layer directly below it, which is our "Stars" layer. The original image on the Background layer will not be affected by anything we do. Click inside the checkbox to select the option:

Then click OK to exit out of the dialog box, at which point the Levels dialog box appears.

Step 10: Reduce The Amount Of Visible Noise To Create The Stars

The most noticeable feature inside the Levels dialog box is a large black graph in the center, which is called a Histogram, and without getting into unnecessary details, it shows us how the tonal range of our image is being distributed. In other words, it shows us how much of our image is dark, how much is light, and how much falls somewhere in between.

If you're not that familiar with Levels or the Histogram, don't worry. We don't need to know any of this in order to create our stars effect. What we're interested in is directly below the Histogram. You'll see three small sliders - a black one on the left, a white one on the right and a gray one in the middle. Normally, we use these sliders to adjust the contrast in an image, but in this case, we're simply going to use them to reduce the amount of noise we're seeing on our "Stars" layer so that what we're left with looks more like, well, stars!

First, click on the white slider and drag it a little towards the left. As you drag, you'll see the noise in the image becoming brighter. You won't need to drag this slider very far. Just drag it enough to brighten the noise a little. Then click on the black slider and begin dragging it towards the right. As you drag this slider, you'll see the darkest areas of noise begin to fade away, and as you continue dragging towards the right, more and more of the noise will fade away. Continue dragging the black slider to the right until so much of the noise has faded away that all you're left with is a few random dots scattered around in the sky. These are the stars! Here's a screenshot of my Levels dialog box after dragging the sliders. Notice how the white slider was dragged only a little to the left, but the black slider needed to be dragged far over to the right in order to remove most of the noise from the image (the middle gray slider will move on its own as you drag the white and black sliders):

Fine-tune the number of stars in your sky, as well as their overall brightness, by moving the sliders a little to the left and right until you're happy with the results in your image, then click OK to exit out of the dialog box. Here's my image after removing most of the noise and creating my stars:

If you decide you're not quite as happy with the way they look as you thought you were and you want to fine-tune them some more, you can easily do that thanks to the power of Adjustment Layers! If we look in the Layers palette, we can see our Levels adjustment layer above the "Stars" layer, and we can see that it's indented over to the right with a small arrow on the left pointing down at the "Stars" layer below it. This is telling us that the layer is being "clipped" by the layer below it thanks to that "Use Previous Layer As Clipping Mask" option we selected a moment ago, which means that it's only affecting the "Stars" layer:

If at any time you want to make changes to the Levels adjustment layer, all you need to do is double-click on the layer's thumbnail in the Layers palette, and the dialog box will reappear, allowing you to make your changes:

I'm pretty happy with the number of stars I have in my image, so I'll leave my sliders in the adjustment layer alone. The only thing I'm not happy with at the moment is that the image looks a little fake. The original photo had a nice warm glow rising into the sky from all the city lights, but at the moment, that glow is missing, as if the light from the city suddenly gets cut off by the sky, which is a bit unnatural. Let's bring back the glow, and we'll do that next!