One of the best parts of image editing is working on fun projects, and making glowing eyes is an idea that every image editor wants to try at some point.
The process isn’t too complicated, and it’s a great way to sharpen your GIMP editing skills while having some fun.
Without any further introduction, let’s take a look at how to make glowing eyes in GIMP!
Step 1: Duplicate the Image
The first step in this edit is to make a duplicate copy of your main image on a new layer, which is very easy to do.
Use the keyboard shortcut Ctrl + Shift + D (use Command + Shift + D if you’re using GIMP on a Mac), or you can open the Layer menu and click Duplicate Layer. You can also right-click your layer in the Layers panel and select Duplicate Layer from the popup menu.
The duplicate layer will get adjusted to create the glow effect, but you can use a layer mask to hide everything on this layer except the eyes. Because the duplicate layer’s positioning matches perfectly with the original layer, only the subject’s eyes will appear to glow!
Step 2: Layer Masking
There are two ways you can perform this step, depending on which tool you’re more comfortable working with: the Paintbrush tool or the Free Select tool. The results are the same, so it really comes down to personal choice.
If you have a drawing tablet, you might find it easier to use the Paintbrush method, while the Free Select method works well with a mouse.
Using Free Select
If you prefer to use the Free Select tool, switch to the tool using the Toolbox or the keyboard shortcut F.
Click anywhere on the edge of your subject’s eyes to start the selection process, then move the cursor a short way around the border of the eye, and click again to place a second point. Continue placing points around one eye until it is completely selected.
You can re-adjust any of the points you’ve placed to fine-tune your selection, which is a very helpful feature of this tool.
Once you’re happy with the selection around one eye, go to the Tool Options panel and change the Mode setting to Add (as shown above) before you start working on the next selection around the second eye.
This will ensure that you add to your existing selection instead of replacing it.
Alternatively, you can simply hold down the Shift key and start placing points around the second eye, but if you let go of the Shift key at any point while placing points, you’ll have to start the whole selection process from scratch!
Once you’ve completed your selection, it’s time to add the layer mask. Make sure that you’ve still got your duplicate layer selected, and then click the Add Layer Mask button at the bottom of the Layers panel, as highlighted below.
GIMP will display the Add Layer Mask dialog. Since there was an active selection when you clicked the button, the Add Layer Mask dialog should automatically be set to Selection, but if not, you can set it yourself by clicking the radio button.
Click the Add button, and a new mask will be created, and a new thumbnail will appear in the Layers panel. The thumbnails are a bit too small to see fine details, but everything on the duplicate layer is now transparent except for the selected areas you created around the eyes.
Using the Paintbrush
If you’d prefer to use the Paintbrush tool method, you need to add a layer mask first.
Make sure the duplicate layer is selected in the Layers panel, then click the Add Layer Mask button at the bottom of the Layers panel, as shown below.
GIMP will open the Add Layer Mask dialog. Set the Initialize Layer Mask to: White (full opacity) and click Add. A new thumbnail will be added next to the duplicate layer, indicating that there is a layer mask.
Click the small eyeball icon next to the original layer to make it invisible. This will allow you to paint out the eyes on the duplicate layer mask, and the transparency grid will help you determine where the mask is being applied.
Switch to the Paintbrush tool using the Toolbox or the keyboard shortcut B, and then click the new layer mask thumbnail in the Layers panel to select it.
Set your foreground color to black, and then begin painting overtop of the subject’s eyes. Since you’re painting black onto the layer mask, the eyes will be turned transparent, and since the layer below is invisible, you’ll see the transparency grid showing through the empty space. It looks a bit spooky, actually!
Once you’re done, open the Colors menu and click Invert. This will invert the black-and-white tones of the layer mask, and suddenly, only your subject’s eyes will be visible.
Click the missing eyeball icon located next to the original layer to make it visible again, and the hard part is over. Your image should now look the same as it did before, except now there is an isolated copy of the eyeballs ready to glow.
Step 3: Adjust the Brightness
Now that all the setup is out of the way, it’s time to make those eyes glow! There are several different ways that you can accomplish this, but the simplest method is to use the Curves tool.
Make sure that you click the pixel thumbnail in the Layers panel to select it, or all the edits will be applied to the layer mask instead.
Open the Colors menu and select Curves. In the Curves dialog window, place your cursor over the center of the histogram grid (as shown below), then click and drag upwards.
This will increase the brightness of the midtones on the selected layer, but because there is a layer mask hiding the rest of the subject, it makes glowing eyes!
You can also add additional points in the Curves tool to customize the glow effect. If you want to learn more about Curves, check out my tutorial on how to use the Curves tool in GIMP.
Once you’re happy with the glowing eyes effect, click OK.
At this point, you might notice that your original layer mask wasn’t quite perfect. If you want to refine the mask, you can edit it as much as you want using the Paintbrush tool.
Click the mask thumbnail to select it, and then switch to the Paintbrush tool. Press D to reset the foreground and background colors to black and white, then start painting onto the layer mask. Anywhere that you paint white becomes visible, and anywhere you paint black becomes transparent.
Optional: Change the Glowing Eye Color
If you want, you can also change the color of your subject’s eyes by using the Hue-Saturation tool. Because you already isolated the eyes to make them glow, this step is an easy add-on project that can really make those eyes go wild!
Open the Colors menu, and select Hue-Saturation. Adjust the Hue slider to change the color of your subject’s eyes, and you can tweak the Lightness and Saturation sliders to enhance the effect.
You can also use any other tools in the Colors menu to adjust the eye glow effect until you get the results you want, but if you plan to do a lot of experimenting, you should make another copy of your eyes layer so that you have a backup in case something goes wrong and you run out of Undo steps.
A Final Word
Congratulations, you just learned how to make glowing eyes in GIMP! Like most image editing projects, there are lots of ways that you can go about achieving a similar result, but I think this is the simplest way to do it while still following good workflow habits.
You could simply edit the eyes directly instead of using a duplicate layer and layer mask, but it’s always worth taking the time to do things properly.
Enjoy your glowing eyes!About Thomas Boldt