Create A Starry Sky In Photoshop

Step 4: Apply The "Gaussian Blur" Filter To The Noise

Now that we've filled our "Stars" layer with noise, we need to blur it out just a little bit. To do that, go up to the Filter menu once again at the top of the screen, and this time choose Blur, and then choose Gaussian Blur. This brings up the "Gaussian Blur" dialog box. We want just a slight amount of blurring here, so set the Radius value at the bottom of the dialog box to around 0.3 pixels:

Click OK to exit out of the dialog box and apply the filter. Your noise should know appear blurred slightly and a bit "softer" looking in your image.

Step 5: Hide The "Stars" Layer Temporarily

We've done everything we need to do on the "Stars" layer for the moment, and at this point we need to see our original photo again. Problem is, our original photo is currently being blocked from view by the "Stars" layer above it, so we need to temporarily hide the "Stars" layer. To do that, click on its Layer Visibility icon, which is the icon that looks like a little eyeball on the left side of the layer in the Layers palette:

When you click on the icon, the eyeball will disappear, which indicates that the layer is no longer visible inside the Photoshop document. Clicking again in that spot will turn the layer back on, and the eyeball will reappear. For now though, just leave the layer hidden so we can see our original photo.

Step 6: Select The Sky Area In The Photo

Now that the "Stars" layer is hidden and we can see our original photo once again, use the selection tool of your choice to draw a selection around the sky so that only the sky (the area where we want the stars to appear) is selected, while everything below the sky (the area where we don't want the stars to appear) is not selected. Depending on your image, you may be able to get away with simply clicking inside the sky area with the Magic Wand, but in most cases, you'll probably need to use something else, like the Lasso Tool or the Pen Tool. In my case, since everything below the sky is a building or tower and made up mostly of straight lines, I used the Polygonal Lasso Tool, which is hiding behind the regular Lasso Tool in the Tools palette. The Polygonal Lasso Tool was built specifically for selecting objects made up of straight lines, which makes it perfect for drawing selections around buildings. Here's my image with the sky selected:

Step 7: Turn The "Stars" Layer Back On

With the sky area now selected, click once again on its Layer Visibility icon on the left of the layer in the Layers palette. Just click inside the empty square where the eyeball was showing a moment ago:

Step 8: Add A Layer Mask

At this point, you should still have the "Stars" layer selected in the Layers palette, but if for some reason you don't, click on it to select it. We're going to add a layer mask to the layer, which is going to be used to hide the stars in areas of the photo where we don't want them to appear. We've already selected our sky area, and whenever you add a layer mask to a layer with part of your image selected, Photoshop creates the layer mask based on your selection. In other words, it says "Okay, you want the part of the layer that's inside the selection to remain visible, and you want everything outside of the selection to be hidden from view. Got it!". Let's add our layer mask to see what I mean.

To add a layer mask, all we need to do is click on the Layer Mask icon at the bottom of the Layers palette:

If we look at the "Stars" layer now, we can see the layer mask thumbnail that's been added, which gives us a preview of what our mask looks like. Notice how the area along the bottom of the thumbnail (the area that was not selected) appears black, while everything else (the area that was selected) appears white:

If you need more information on how layer masks work, be sure to check out our Understanding Layer Masks tutorial. If we look back at our image now, we can see the noise once again, but the noise is now appearing only in the sky area of the photo thanks to our layer mask:

And we're done! Doesn't that look great?!

Okay, seriously. We're not done. We're going to turn all that noise into some stars using a Levels adjustment layer next!