You just dropped three grand on a flagship OLED. You’ve got the perfect black levels, the 120Hz refresh rate, and enough peak brightness to burn your retinas. You hook up your Sega Genesis, fire up Sonic the Hedgehog, and… it looks like absolute garbage.
The legendary waterfalls in Green Hill Zone? They aren’t transparent; they’re a series of vertical blue stripes. The smooth gradients in Streets of Rage 2? They look like a grainy mess of checkerboard dots.
You haven’t been lied to about Blast Processing, but you are missing a critical piece of the puzzle: The display was part of the art. Back in the 90s, Sega’s artists weren’t just drawing pixels; they were exploiters of physics. They knew exactly how a Cathode Ray Tube (CRT) would smear their work into a masterpiece. By putting your Genesis on a modern digital display, you aren’t seeing a clearer version of the game—you’re seeing a broken one.
The Dithering Illusion: Math Meets Magic
The Sega Genesis had a notorious technical limitation: a color palette of only 512 colors, with only 64 on-screen at once. Compared to the Super Nintendo’s 32,768 colors, Sega was bringing a knife to a gunfight.
To compensate, developers used dithering. By placing two different colored pixels in a checkerboard or jailbar pattern, they relied on the CRT’s inherent lack of precision to blend those colors together in your brain.
The Waterfall Effect: In Sonic 1, the waterfall is just alternating vertical lines of blue and white. On a CRT, these lines bleed into each other, creating a perfect translucent blue.
The Transparency Hack: Since the Genesis lacked hardware-level transparency, dithering allowed for fake shadows and light beams.
Color Expansion: By dithering colors together, artists could trick the eye into seeing thousands of shades that didn’t technically exist in the hardware’s RAM.
On your 4K TV, those pixels are mapped with surgical precision. There is no bleed. There is no blending. The illusion is shattered, leaving you with “jailbars” and checkerboards that look like a technical error.
Physics of the Tube: Why CRTs Fixed Graphics
To understand the fix, we have to understand the physics of the problem. A CRT doesn’t show a static image; it paints one with a literal gun.
1. The Electron Beam: A CRT fires a stream of electrons at a phosphor-coated screen. This beam moves in a raster scan, hitting the phosphors and making them glow.
2. Phosphor Bleed: When a phosphor is struck, the light doesn’t stay confined to a perfect square. It “blooms” or bleeds into the neighboring phosphors. This analog blurring is what perfectly blended the Genesis’s dithering patterns.
3. Scanline Physics: In the 240p mode used by retro consoles, the CRT only draws the even-numbered lines. This leaves a tiny, physical black gap between the rows of light. These are the scanlines. They provide a natural anti-aliasing effect, making low-resolution art look significantly sharper and more detailed than it actually is.
Modern LCDs and OLEDs use fixed-pixel arrays. A pixel is either on or off. There is no bloom, no natural scanline gap, and—most importantly—no mercy for low-resolution assets.
The Modern Solution: Enter the RetroTink
If you want to play on a big screen without hunting down a 100-pound Sony Trinitron, you need an upscaler. But not just any $20 Amazon adapter—you need a device that can simulate the physics of a CRT.
The RetroTink 5X-Pro and the newer, earth-shaking RetroTink 4K are the current gold standards. These aren’t just converters; they are powerful FPGA-based computers designed to reconstruct the analog signal.
Bilinear Interpolation & Masks: These devices allow you to add masks that simulate the phosphor structure of a real TV (Aperture Grille or Shadow Mask).
Adaptive Scanlines: You can dial in the exact thickness and “bloom” of the scanlines, mimicking the look of a high-end Broadcast Video Monitor (BVM).
Dither Blending: The RetroTink 4K features advanced filters that specifically target jailbars and checkerboard patterns, blending them back into the transparent effects the artists intended.
Black Frame Insertion (BFI): Solving the Motion Blur
There is one more hurdle: Sample-and-Hold blur. On a modern TV, a frame stays on-screen until the next one is ready. This creates ghosting as your eyes track moving objects. On a CRT, the image is pulsed; it flashes and decays almost instantly. This is why retro games feel smoother on old tech.
The solution is Black Frame Insertion (BFI). High-end TVs and the RetroTink 4K can insert a black frame between every active frame of the game. This mimics the pulsing light of a CRT, effectively killing motion blur and bringing back that 1992 arcade-perfect clarity.
The RetroTink 4K takes this a step further with Rolling BFI, which simulates the electron beam moving down the screen. It is, quite literally, the closest you can get to a tube without the vacuum glass.
The Hardware Angle
Retro gaming isn’t just about the software; it’s about the Hardware-Software Synergy. The Sega Genesis was designed as one half of a system, with the CRT being the other half. When you remove the CRT, you’re looking at an unfinished painting.
If you’re serious about the 16-bit era, stop settling for the raw pixels your TV gives you. Invest in the right scaling hardware, turn on those scanlines, and let the phosphors (even the emulated ones) do their job. Your eyes—and Sonic—will thank you.