Short answer: For LED diffusers, 1/8 in. white translucent acrylic hides LED hot spots best, while frosted acrylic lets more light through with a softer, satin look. The bigger factor is distance: keep the LEDs at least as far behind the diffuser as they are apart from each other, and the glow will look even.
White translucent or frosted?
Both scatter light, but they do it differently, and the right one depends on how close the LEDs are.
| White translucent | Frosted | |
|---|---|---|
| Look when lit | Bright, milky, even white | Soft glow, slightly see-through |
| Hides LED dots | Very well, even close up | Well, if the LEDs are a few inches back |
| Light let through | Less; you lose some brightness | More |
| Look when off | Solid white | Satin, like etched glass |
| Thicknesses | 1/8 to 3/8 in. | 1/8 to 3/8 in. |
White translucent is the choice for shallow fixtures, light boxes, and signs where you can't see any individual LEDs. Frosted suits shelf lighting, decorative panels, and places where you want the panel to look like glass when the lights are off. More on frosted acrylic options and how much light each type lets through.
How far should the LEDs be from the diffuser?
This matters more than the sheet you choose. A simple rule: the gap between LEDs and diffuser should be at least equal to the spacing between LEDs.
- LED strip in a channel, 1/2 in. deep: use white translucent. Frosted will show dots.
- Light box 2 to 4 in. deep with strips 3 in. apart: either works; frosted is brighter.
- Ceiling fixture 4 in. or more deep: frosted or white translucent, depending on the look you want.
If you can't add depth, add density: closer-spaced strips or high-density LED tape helps more than a thicker panel.
What thickness to use
For diffusing, 1/8 in. does the job. Thickness is about stiffness, not light:
- 1/8 in. for strip covers, small light boxes, and panels supported on all edges up to about 24 × 24 in.
- 3/16 in. for ceiling panels and light boxes up to about 24 × 48 in. that rest on a frame.
- 1/4 in. when the diffuser is also a shelf or a step, or spans a long distance with little support. A backlit shelf needs the strength; check it with the shelf sag calculator.
Heat and mounting
LEDs run cool enough for acrylic. The limit to keep in mind is about 160 °F (70 °C) continuous. Keep diffusers well away from incandescent and halogen bulbs, which can soften and warp acrylic over time. If you're retrofitting an old fluorescent fixture, switch to LED tubes or strips first.
Acrylic grows about 0.04 in. per 48 in. for every 20 °F of temperature change, so leave a little room in the frame or channel. Diffusers that sit in a groove or lay on a ledge don't need holes at all. If you screw a panel down, drill the holes oversize and don't clamp hard. The thermal expansion calculator gives the gap for your size.
Design tips
- Round the corners slightly (1/8 in. radius) on panels that drop into a frame. They're easier to fit and less likely to chip.
- Cut light-box faces with the logo or lettering as a separate piece in a colored sheet, and the diffuser behind it in white translucent.
- For a strip channel, order covers a hair narrower than the channel's slot so they slide in without bowing.
Tip: want light to come out of the edges instead of the face? That's edge lighting, and it uses clear acrylic. See edge-lit LED signs.
Enter your panel size in the instant quote and choose white translucent or frosted.
Questions
Will an acrylic diffuser turn yellow?
Good-quality acrylic resists yellowing much better than most plastics, and LEDs give off very little UV. An indoor LED diffuser should stay white for many years.
Can you replace a cracked ceiling light panel?
Yes. Measure the opening and the old panel's thickness, and we'll cut a new one in white translucent or frosted. Bring or describe the original and we'll suggest the closest match.