How to Create Frosted Glass in Paint.NET

The frosted glass or glassmorphism effect is a popular design technique that blurs background imagery beneath a translucent, highlighted foreground element. In this guide, you will learn how to create this effect in Paint.NET by isolating your target area, applying a Gaussian blur to simulate diffusion, and layering semi-transparent fills and subtle border highlights to give the element a realistic, frosted appearance.

Step 1: Prepare Your Background

  1. Open Paint.NET and load the image you want to use as your background (Ctrl + O).
  2. Open the Layers window (F7 if not visible).
  3. Right-click the background layer, select Duplicate Layer, and rename this new layer to "Blurred Background."

Step 2: Apply the Blur

  1. Select the "Blurred Background" layer.
  2. Navigate to the top menu and click Effects > Blurs > Gaussian Blur.
  3. Adjust the Radius slider to achieve the desired level of diffusion. A value between 20 and 40 pixels usually produces a convincing frosted look.
  4. Click OK to apply the blur.

Step 3: Define the Glass Shape

  1. Add a new layer above the "Blurred Background" layer and name it "Glass Panel."
  2. Choose the Shapes tool from the toolbar (O), select the Rounded Rectangle shape, and set the fill style to Draw Filled Shape.
  3. Set your primary color to solid white.
  4. Draw the shape on the "Glass Panel" layer where you want the frosted window to appear.

Step 4: Mask the Blurred Area

  1. With the "Glass Panel" layer selected, use the Magic Wand tool (S) to select the interior of your shape.
  2. Switch to the "Blurred Background" layer while keeping the selection active.
  3. Invert the selection by pressing Ctrl + I.
  4. Press Delete on your keyboard. This removes the blurred background everywhere except directly beneath your glass shape.
  5. Press Ctrl + D to deselect.

Step 5: Adjust Transparency and Tint

  1. Select the "Glass Panel" layer.
  2. Double-click the layer (or press F4) to open Layer Properties.
  3. Lower the Opacity slider to a value between 30 and 60 depending on how frosted you want the glass to look.
  4. Click OK.

Step 6: Add Borders and Noise for Realism

  1. Add a new layer at the very top and name it "Glass Border."
  2. Reselect the shape outline on the "Glass Panel" layer using the Magic Wand.
  3. Switch to the "Glass Border" layer, choose the Shapes tool set to Draw Shape Outline, set the brush width to 1 or 2 pixels, and trace the edge in white. Reduce this layer's opacity to roughly 100–120 for a soft glass edge.
  4. (Optional Texture) Select the "Glass Panel" layer, go to Effects > Noise > Add Noise, and set the intensity very low (between 5 and 10) to replicate the microscopic rough surface of real frosted glass.