diff --git a/imagewidget.cpp b/imagewidget.cpp
index 3f5ca8a..7bd69a0 100644
--- a/imagewidget.cpp
+++ b/imagewidget.cpp
@@ -777,7 +777,7 @@ void ImageWidgetGL::initializeGL()
     m_lut->bind(2);
 
     QImage colormap = loadColormap();
-    m_colormap = std::make_unique<QOpenGLTexture>(QOpenGLTexture::Target1DArray);
+    m_colormap = std::make_unique<QOpenGLTexture>(QOpenGLTexture::Target2DArray);
     m_colormap->setSize(colormap.width());
     m_colormap->setLayers(colormap.height());
     m_colormap->setFormat(QOpenGLTexture::RGBA8_UNorm);
diff --git a/shaders/image.frag b/shaders/image.frag
index e311e7e..3c7a801 100644
--- a/shaders/image.frag
+++ b/shaders/image.frag
@@ -1,6 +1,6 @@
 uniform sampler2D qt_Texture0;
 uniform sampler3D lut_table;
-uniform sampler1DArray colormap;
+uniform sampler2DArray colormap;
 uniform vec3 mtf_param[3];
 uniform vec2 unit_scale;
 uniform bool bw;
@@ -30,7 +30,7 @@ vec3 falsecolor(float color)
 {
     color *= 255.0 / 256.0;
     color += 0.5 / 256.0;
-    return texture(colormap, vec2(color, colormapIdx)).rgb;
+    return texture(colormap, vec3(color, 0.5, colormapIdx)).rgb;
 }
 
 vec3 checker()