diff --git a/README.md b/README.md
index befb37a..bb8f35e 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-> Package captcha provides an easy to use, unopinionated API for captcha generation
+> Package captcha provides an easy to use, unopinionated API for captcha generation.
 
 <div>
 
@@ -42,7 +42,7 @@ func handle(w http.ResponseWriter, r *http.Request) {
 
 ## Contributing
 If your found a bug, please contribute!
-see [contributing.md](contributing.md) for more detail
+see [contributing.md](contributing.md) for more detail.
 
 ## License
 [MIT](LICENSE.md)
diff --git a/captcha.go b/captcha.go
index 28e2ea9..90d2f14 100644
--- a/captcha.go
+++ b/captcha.go
@@ -258,7 +258,7 @@ func randomInvertColor(base color.Color) color.Color {
 	hue := float64(rng.Intn(361)) / 360
 	saturation := 0.6 + rng.Float64()*0.2
 
-	return hsva{h: hue, s: saturation, v: value, a: uint8(255)}
+	return hsva{h: hue, s: saturation, v: value, a: 255}
 }
 
 func getLightness(colour color.Color) float64 {