Create Frosted Glass UI Cards in GIMP

This guide explains how to design a modern glassmorphism UI card featuring a realistic frosted glass aesthetic in GIMP. You will learn how to produce the characteristic translucent blur, apply soft color tinting, create reflective border highlights, and cast subtle drop shadows to make your interface components stand out over any background.

Step 1: Prepare the Background

Glassmorphism relies entirely on the background behind it to create the illusion of transparency and refraction.

  1. Open GIMP and create a new project with your desired canvas size.
  2. Fill the background with a vibrant, colorful gradient or an abstract image with contrasting light and dark areas. Pure solid colors will make the frosted blur effect difficult to notice.

Step 2: Define the Card Shape

  1. Create a new transparent layer above your background and name it Card Shape.
  2. Select the Rectangle Select Tool (R).
  3. In the Tool Options panel, check the Rounded Corners option and set the radius (e.g., 20px to 30px depending on canvas resolution).
  4. Draw your card's shape on the canvas. Keep the selection active for the subsequent steps.

Step 3: Create the Frosted Blur Effect

  1. Click on the background layer in the Layers panel.
  2. Press Ctrl + C then Ctrl + V to paste the selection, and click the green anchor icon or go to Layer > To New Layer to convert it into its own layer. Name this layer Blurred Background.
  3. Move Blurred Background above the original background layer.
  4. With Blurred Background selected, navigate to Filters > Blur > Gaussian Blur.
  5. Adjust the Size X and Size Y sliders to between 25 and 50 pixels depending on how heavy you want the frosted diffusion to appear, then click OK.

Step 4: Add the Translucent Tint

  1. Select the Card Shape layer you created earlier.
  2. Reactivate the card selection if it was deselected (right-click the Card Shape or Blurred Background layer and choose Alpha to Selection).
  3. Select the Bucket Fill Tool (Shift + B) and set the foreground color to pure white (#FFFFFF).
  4. Fill the active selection on the Card Shape layer.
  5. In the Layers panel, lower the Opacity of the Card Shape layer to between 10% and 25%. This adds the milky, semi-opaque surface characteristic of frosted glass.

Step 5: Add the Subtle Border Stroke

Light catches the physical edges of glass, so a thin highlight stroke is essential.

  1. Create a new transparent layer at the top of the layer stack and name it Border.
  2. Ensure your card outline selection is still active.
  3. Go to Select > Border. Set the border width to 1px or 2px, set the style to Smooth, and click OK.
  4. Fill this border selection with pure white (#FFFFFF).
  5. Deselect the area using Select > None (Ctrl + Shift + A).
  6. Set the Border layer's opacity to roughly 30% to 50% to prevent the line from looking too harsh. For enhanced realism, you can add a layer mask with a linear gradient to make the border fade from bright white at the top-left to transparent at the bottom-right.

Step 6: Add Depth with a Drop Shadow

  1. Right-click the Blurred Background layer and choose Alpha to Selection.
  2. Create a new layer immediately above the original background (below Blurred Background) and name it Shadow.
  3. Go to Filters > Light and Shadow > Drop Shadow.
  4. Set X to 0, Y to 10–15px, and Blur Radius to 30–40px.
  5. Set the shadow color to black and decrease the Opacity to approximately 0.2 to 0.3 for a soft, modern ambient occlusion effect. Click OK to apply.