Bleeding Edge: Make Image Colors Extend Beyond Borders

This blog outlines how to implement a visual effect often referred to as a bleeding edge. This technique creates the appearance of an image’s colors softly extending beyond its borders, producing a diffused, blurred halo effect.

We show you two ways to implement this:

1. TailwindCSS approach using before pseudo-elements
2. Next.js <Image /> approach using layered components

Both approaches are compatible with a range of layout contexts including hero banners, grid cards, content showcases, and more.

Let’s dive in.

Method 1: TailwindCSS Approach

This approach uses Tailwind’s utility classes to blur a duplicated background via the before pseudo-element. This is a simple approach that is suitable for when dynamic image handling is not required or when you want to avoid duplicating image nodes and keep markup minimal.

1<div className="relative bg-[url('{INSERT IMAGE PATH}')] bg-cover before:absolute before:inset-0 before:-z-10 before:bg-[url('{INSERT IMAGE PATH}')] before:bg-cover before:opacity-80 before:blur-md">
2  <p>Optional Text</p>
3</div>

Technical Notes

CSS filter: blur() affects the rendered pixels, not the DOM boundary. So when we blur that pseudo-element, it naturally bleeds beyond the parent’s edges.

The setup:

• Parent container has the background image (bg-[url(...)]).
• A ::before pseudo-element is positioned absolutely and layered behind the original image (with -z-10), covering the exact same space (before:inset-0).
• This pseudo-element uses the same image URL to replicate the background, which ensures alignment.
• The before:blur-md (adjust as needed) class applies a blur filter to soften the duplicated background, creating the bleeding effect beyond the original image’s bounds.

Opacity (before:opacity-80) can be adjusted as needed to ensure the blur is subtle and does not overpower the foreground content.

Method 2: Next.js <Image /> Approach

This method involves rendering two layers of the same image: a blurred version positioned behind a sharp foreground image. This approach is suitable for when dynamic image content is required or for image-heavy applications requiring Next.js image optimization.

1<div>
2  {/* Background image (bleeding edge) */}
3  <div className="absolute inset-0 -z-10 opacity-80">
4    <Image
5      src="{INSERT IMAGE PATH}"
6      alt=""
7      fill
8      style={{
9        objectFit: "cover",
10        objectPosition: "top",
11        filter: "blur(12px)",
12      }}
13    />
14  </div>
15  {/* Main foreground image */}
16  <Image
17    src="{INSERT IMAGE PATH}"
18    alt="{INSERT IMAGE ALT TEXT}"
19    fill
20    style={{
21      objectFit: "cover",
22      objectPosition: "top",
23      zIndex: -5,
24    }}
25  />
26  <p className="z-10">Optional Text</p>
27</div>

Technical Notes

By applying filter: blur() to just one layer while keeping the other sharp, we get a non-destructive blur effect. The fill prop and objectFit: “cover” keep both images perfectly aligned across different screen sizes.

The setup:

• The background layer is rendered using a <div> containing a Next.js <Image /> component.
• This image is configured with fill (causing it to occupy the full size of its container), and a filter:blur(12px) (adjust as needed) style, which produces a stronger, more ambient halo.
• opacity-80 softens the intensity of the blur so it blends into the background.
• Above this, a second <Image /> component renders the same image in focus. This also uses fill for perfect spatial alignment.

Layering is achieved by using absolute positioning to stack both blurred and sharp images in the same space, while zIndex controls their visual order to ensure the blurred image sits behind the clear one.

Concluding Thoughts

Now that the mechanics are clear, use whichever approach fits your stack.

Remember, the possibilities for customization are endless: try scoping the blur direction by using before:scale-x-105 or before:scale-y-125 to simulate directional glow.

Not sure which method to choose?

• Use the TailwindCSS approach when dealing with static assets and seeking minimal markup.
• Opt for the Next.js <Image /> approach when handling dynamic image content, and when image optimization is critical.

Got questions about this implementation or need help with one of your projects? Reach out to us at hello@theneurallab.com or use our contact form.

Happy shipping! 🚢