diff --git a/zenovis/xinxinoptix/PTKernel.cu b/zenovis/xinxinoptix/PTKernel.cu
index a199625b0..14aaffbc1 100644
--- a/zenovis/xinxinoptix/PTKernel.cu
+++ b/zenovis/xinxinoptix/PTKernel.cu
@@ -441,8 +441,8 @@ extern "C" __global__ void __raygen__rg()
     auto uv = float2{idx.x+0.5f, idx.y+0.5f};
     auto dither = InterleavedGradientNoise(uv);
 
-    dither = (dither-0.5f)/255;
-    params.frame_buffer[ image_index ] = make_color( accum_color + dither);
+    dither = (dither-0.5f);
+    params.frame_buffer[ image_index ] = makeSRGB( accum_color, 2.2f, dither);
 
     if (params.denoise) {
         params.albedo_buffer[ image_index ] = tmp_albedo;
diff --git a/zenovis/xinxinoptix/SDK/cuda/helpers.h b/zenovis/xinxinoptix/SDK/cuda/helpers.h
index b98b6bb5b..142927e0e 100644
--- a/zenovis/xinxinoptix/SDK/cuda/helpers.h
+++ b/zenovis/xinxinoptix/SDK/cuda/helpers.h
@@ -32,9 +32,9 @@
 #include <sutil/vec_math.h>
 
 
-__forceinline__ __device__ float3 toSRGB( const float3& c )
+__forceinline__ __device__ float3 toSRGB( const float3& c, float gamma )
 {
-    float  invGamma = 1.0f / 2.4f;
+    float  invGamma = 1.0f / gamma;
     float3 powed    = make_float3( powf( c.x, invGamma ), powf( c.y, invGamma ), powf( c.z, invGamma ) );
     return make_float3(
         c.x < 0.0031308f ? 12.92f * c.x : 1.055f * powed.x - 0.055f,
@@ -42,11 +42,6 @@ __forceinline__ __device__ float3 toSRGB( const float3& c )
         c.z < 0.0031308f ? 12.92f * c.z : 1.055f * powed.z - 0.055f );
 }
 
-//__forceinline__ __device__ float dequantizeUnsigned8Bits( const unsigned char i )
-//{
-//    enum { N = (1 << 8) - 1 };
-//    return min((float)i / (float)N), 1.f)
-//}
 __forceinline__ __device__ unsigned char quantizeUnsigned8Bits( float x )
 {
     x = clamp( x, 0.0f, 1.0f );
@@ -54,13 +49,17 @@ __forceinline__ __device__ unsigned char quantizeUnsigned8Bits( float x )
     return (unsigned char)min((unsigned int)(x * (float)Np1), (unsigned int)N);
 }
 
-__forceinline__ __device__ uchar4 make_color( const float3& c )
+__forceinline__ __device__ uchar4 makeSRGB( const float3& c, float gamma=2.2f, float dither=0.0f)
 {
     // first apply gamma, then convert to unsigned char
-    float3 srgb = toSRGB( clamp( c, 0.0f, 1.0f ) );
+    float3 srgb = toSRGB( c, gamma );
+    //srgb += make_float3(dither);
+    srgb += make_float3(dither, 1.0-dither, dither)/255;
+    srgb = clamp( srgb, 0.0f, 1.0f );
+
     return make_uchar4( quantizeUnsigned8Bits( srgb.x ), quantizeUnsigned8Bits( srgb.y ), quantizeUnsigned8Bits( srgb.z ), 255u );
 }
 __forceinline__ __device__ uchar4 make_color( const float4& c )
 {
-    return make_color( make_float3( c.x, c.y, c.z ) );
+    return makeSRGB( make_float3( c.x, c.y, c.z ) );
 }