diff --git a/src/map.jl b/src/map.jl
index ca602f7d..f611bcc1 100644
--- a/src/map.jl
+++ b/src/map.jl
@@ -102,6 +102,15 @@ similar{T,F}(mapi::Clamp, ::Type{T}, ::Type{F}) = Clamp{T}()
 map{T<:Real,F<:Real}(mapi::ClampMin{T,F}, val::F) = convert(T, max(val, mapi.min))
 map{T<:Real,F<:Real}(mapi::ClampMax{T,F}, val::F) = convert(T, min(val, mapi.max))
 map{T<:Real,F<:Real}(mapi::ClampMinMax{T,F}, val::F) = convert(T,min(max(val, mapi.min), mapi.max))
+map{T<:Fractional,F<:Real}(mapi::ClampMin{Gray{T},F}, val::F) = convert(Gray{T}, max(val, mapi.min))
+map{T<:Fractional,F<:Real}(mapi::ClampMax{Gray{T},F}, val::F) = convert(Gray{T}, min(val, mapi.max))
+map{T<:Fractional,F<:Real}(mapi::ClampMinMax{Gray{T},F}, val::F) = convert(Gray{T},min(max(val, mapi.min), mapi.max))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMin{Gray{T},F}, val::Gray{F}) = convert(Gray{T}, max(val, mapi.min))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMax{Gray{T},F}, val::Gray{F}) = convert(Gray{T}, min(val, mapi.max))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMinMax{Gray{T},F}, val::Gray{F}) = convert(Gray{T},min(max(val, mapi.min), mapi.max))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMin{Gray{T},Gray{F}}, val::Gray{F}) = convert(Gray{T}, max(val, mapi.min))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMax{Gray{T},Gray{F}}, val::Gray{F}) = convert(Gray{T}, min(val, mapi.max))
+map{T<:Fractional,F<:Fractional}(mapi::ClampMinMax{Gray{T},Gray{F}}, val::Gray{F}) = convert(Gray{T},min(max(val, mapi.min), mapi.max))
 map1{T<:Union(RGB24,ARGB32),F<:Fractional}(mapi::ClampMin{T,F}, val::F) = convert(Ufixed8, max(val, mapi.min))
 map1{T<:Union(RGB24,ARGB32),F<:Fractional}(mapi::ClampMax{T,F}, val::F) = convert(Ufixed8, min(val, mapi.max))
 map1{T<:Union(RGB24,ARGB32),F<:Fractional}(mapi::ClampMinMax{T,F}, val::F) = convert(Ufixed8,min(max(val, mapi.min), mapi.max))
@@ -111,6 +120,7 @@ map1{CT<:ColorType,F<:Fractional}(mapi::ClampMinMax{CT,F}, val::F) = convert(elt
 
 map{To<:Real}(::Clamp{To}, val::Real) = clamp01(To, val)
 map{To<:Real}(::Clamp{Gray{To}}, val::AbstractGray) = Gray(clamp01(To, val.val))
+map{To<:Real}(::Clamp{Gray{To}}, val::Real) = Gray(clamp01(To, val))
 map1{CT<:AbstractRGB}(::Clamp{CT}, val::Real) = clamp01(eltype(CT), val)
 map1{CT<:AbstractRGB,T}(::Clamp{AlphaColor{CT,T}}, val::Real) = clamp01(T, val)
 map1{CT<:AbstractRGB,T}(::Clamp{AlphaColorValue{CT,T}}, val::Real) = clamp01(T, val)
@@ -427,7 +437,8 @@ for (T,n) in bitshiftto8
     @eval mapinfo(::Type{Gray{Ufixed8}}, img::GrayArray{$T}) = BitShift{Gray{Ufixed8},$n}()
     @eval mapinfo(::Type{GrayAlpha{Ufixed8}}, img::AbstractArray{GrayAlpha{$T}}) = BitShift{GrayAlpha{Ufixed8},$n}()
 end
-mapinfo{T<:Ufixed,F<:FloatingPoint}(::Type{T}, img::AbstractArray{F}) = ClampMinMax(T, zero(F), one(F))
+mapinfo{T<:Ufixed,F<:FloatingPoint}(::Type{T}, img::GrayArray{F}) = ClampMinMax(T, zero(F), one(F))
+mapinfo{T<:Ufixed,F<:FloatingPoint}(::Type{Gray{T}}, img::GrayArray{F}) = ClampMinMax(Gray{T}, zero(F), one(F))
 mapinfo{T<:FloatingPoint, R<:Real}(::Type{T}, img::AbstractArray{R}) = MapNone(T)
 
 mapinfo(::Type{RGB24}, img::Union(AbstractArray{Bool}, BitArray)) = MapNone{RGB24}()
diff --git a/test/map.jl b/test/map.jl
index 6ef8f4cb..acdb405b 100644
--- a/test/map.jl
+++ b/test/map.jl
@@ -119,6 +119,12 @@ mapi = Clamp(BGRA{Ufixed8})
 @chk clamp(ARGB{Float64}(1.2,0.5,-.3,0.2)) ARGB{Float64}(1.0,0.5,0.0,0.2)
 @chk clamp(RGBA{Float64}(1.2,0.5,-.3,0.2)) RGBA{Float64}(1.0,0.5,0.0,0.2)
 
+# Issue #285
+a = [Gray(0xd0uf8)]
+a1 = 10*a
+mapi = mapinfo(Gray{Ufixed8}, a1)
+@chk map(mapi, a1[1]) Gray(0xffuf8)
+
 # ScaleMinMax
 mapi = ScaleMinMax(Ufixed8, 100, 1000)
 @chk map(mapi, 100) Ufixed8(0.0)