diff --git a/lights/src/rgb.rs b/lights/src/rgb.rs
index c585986..2b37c9d 100644
--- a/lights/src/rgb.rs
+++ b/lights/src/rgb.rs
@@ -48,7 +48,7 @@ impl core::ops::Mul<u8> for Rgb
 
 /// Construct an [Rgb] from a monochrome value.
 #[inline]
-pub fn gray(gray: u8) -> Rgb {
+pub const fn gray(gray: u8) -> Rgb {
     Rgb(gray, gray, gray)
 }