diff --git a/src/devices/bus/gio/newport.cpp b/src/devices/bus/gio/newport.cpp
index 9c05b16da79..b4981790ad1 100644
--- a/src/devices/bus/gio/newport.cpp
+++ b/src/devices/bus/gio/newport.cpp
@@ -2794,12 +2794,14 @@ void newport_base_device::do_rex3_command()
 						{
 							case 0: // 4bpp
 								color = m_rex3.m_color_vram & 0xf;
+								color |= color << 4;
 								break;
 							case 1: // 8bpp
 								color = m_rex3.m_color_vram & 0xff;
 								break;
 							case 2: // 12bpp
 								color = ((m_rex3.m_color_vram & 0xf00000) >> 12) | ((m_rex3.m_color_vram & 0xf000) >> 8) | ((m_rex3.m_color_vram & 0xf0) >> 4);
+								color |= color << 12;
 								break;
 							case 3: // 24bpp
 								color = m_rex3.m_color_vram & 0xffffff;
@@ -2873,12 +2875,14 @@ void newport_base_device::do_rex3_command()
 						{
 							case 0: // 4bpp
 								color = m_rex3.m_color_vram & 0xf;
+								color |= color << 4;
 								break;
 							case 1: // 8bpp
 								color = m_rex3.m_color_vram & 0xff;
 								break;
 							case 2: // 12bpp
 								color = ((m_rex3.m_color_vram & 0xf00000) >> 12) | ((m_rex3.m_color_vram & 0xf000) >> 8) | ((m_rex3.m_color_vram & 0xf0) >> 4);
+								color |= color << 12;
 								break;
 							case 3: // 24bpp
 								color = m_rex3.m_color_vram & 0xffffff;