diff --git a/R/bounds.r b/R/bounds.r
index dc4ec157..29e5b77d 100644
--- a/R/bounds.r
+++ b/R/bounds.r
@@ -59,8 +59,10 @@ rescale_none <- function(x, ...) {
 censor <- function(x, range = c(0, 1), only.finite = TRUE) {
   force(range)
   finite <- if (only.finite) is.finite(x) else TRUE
-  x[finite & x < range[1]] <- NA
-  x[finite & x > range[2]] <- NA
+  # Assign NA - this makes sure that, even if all elements are
+  # replaced with NA, it stays numeric (and isn't changed to logical)
+  x[finite & x < range[1]] <- NA_real_
+  x[finite & x > range[2]] <- NA_real_
   x
 }
 
diff --git a/R/scale-continuous.r b/R/scale-continuous.r
index 4e070b8e..70d39cee 100644
--- a/R/scale-continuous.r
+++ b/R/scale-continuous.r
@@ -20,7 +20,7 @@
 #' with(mtcars, plot(disp, mpg, cex = cscale(hp, area_pal())))
 #' with(mtcars, plot(disp, mpg, pch = 20, cex = 5, 
 #'   col = cscale(hp, seq_gradient_pal("grey80", "black"))))
-cscale <- function(x, palette, na.value = NA, trans = identity_trans()) {
+cscale <- function(x, palette, na.value = NA_real_, trans = identity_trans()) {
   stopifnot(is.trans(trans))
   
   x <- trans$trans(x)
@@ -41,7 +41,7 @@ train_continuous <- function(new, existing = NULL) {
 # 
 # @param oob out of bounds behaviour. Defaults to \code{\link{censor}}
 #   which turns oob values into missing values.
-map_continuous <- function(palette, x, limits, na.value = NA, oob = censor) {
+map_continuous <- function(palette, x, limits, na.value = NA_real_, oob = censor) {
   x <- oob(rescale(x, from = limits))
   pal <- palette(x)
   ifelse(!is.na(x), pal, na.value)