diff --git a/Machines/Electron/Video.cpp b/Machines/Electron/Video.cpp
index d5f01194e..2386c93b6 100644
--- a/Machines/Electron/Video.cpp
+++ b/Machines/Electron/Video.cpp
@@ -32,6 +32,13 @@ namespace {
 	static const int real_time_clock_interrupt_2 = 56704;
 	static const int display_end_interrupt_1 = (first_graphics_line + display_end_interrupt_line)*cycles_per_line;
 	static const int display_end_interrupt_2 = (first_graphics_line + field_divider_line + display_end_interrupt_line)*cycles_per_line;
+
+	struct FourBPPBookender: public Outputs::CRT::TextureBuilder::Bookender {
+		void add_bookends(uint8_t *const left_value, uint8_t *const right_value, uint8_t *left_bookend, uint8_t *right_bookend) {
+			*left_bookend = static_cast<uint8_t>(((*left_value) & 0x0f) | (((*left_value) & 0x0f) << 4));
+			*right_bookend = static_cast<uint8_t>(((*right_value) & 0xf0) | (((*right_value) & 0xf0) >> 4));
+		}
+	};
 }
 
 #pragma mark - Lifecycle
@@ -49,6 +56,8 @@ VideoOutput::VideoOutput(uint8_t *memory) : ram_(memory) {
 			"texValue >>= 4 - (int(icoordinate.x * 8) & 4);"
 			"return vec3( uvec3(texValue) & uvec3(4u, 2u, 1u));"
 		"}");
+	std::unique_ptr<Outputs::CRT::TextureBuilder::Bookender> bookender(new FourBPPBookender);
+	crt_->set_bookender(std::move(bookender));
 	// TODO: as implied below, I've introduced a clock's latency into the graphics pipeline somehow. Investigate.
 	crt_->set_visible_area(crt_->get_rect_for_area(first_graphics_line - 3, 256, (first_graphics_cycle+1) * crt_cycles_multiplier, 80 * crt_cycles_multiplier, 4.0f / 3.0f));
 }
diff --git a/Outputs/CRT/CRT.hpp b/Outputs/CRT/CRT.hpp
index cc6c6b903..ee6234521 100644
--- a/Outputs/CRT/CRT.hpp
+++ b/Outputs/CRT/CRT.hpp
@@ -312,6 +312,10 @@ class CRT {
 			});
 		}
 
+		inline void set_bookender(std::unique_ptr<TextureBuilder::Bookender> bookender) {
+			openGL_output_builder_.texture_builder.set_bookender(std::move(bookender));
+		}
+
 		inline void set_output_device(OutputDevice output_device) {
 			enqueue_openGL_function([output_device, this] {
 				openGL_output_builder_.set_output_device(output_device);