Scanlines! It's a phrase often hurled around the retro gaming space, and one you'll find on your "an enthusiast said I'm playing old games wrong" bingo card. The issue is that while it is indeed a visual effect that can be enabled when using emulators and retro console remakes, they won't always make your shiny new screen look like an old CRT TV, and that could put you off using the effect.
As someone who specializes in connecting retro consoles to modern TVs and monitors while also being a CRT TV enthusiast, there is a big fat myth tied to scanlines. While using an overlay that adds horizontal black gaps can enhance definition and add pixel separation, you won't magically get the same visuals as a tube set. There's way more going on with your old idiot box than that, and understanding those old visuals will help set your expectations.
When testing the best retro consoles today or using the originals, I typically enable scanlines. Adding in horizontal black lines can come with caveats, but for the most part, it will add useful pixel separation that helps sprites and textures look less like blocky blobs on modern displays. But, to help you work out whether you actually care about using the effect, I want to dive into what scanlines actually are and the various ways systems today can mimic an old CRT.
What even is a scanline?
By definition, a "scanline" is a horizontal row of pixels drawn rapidly by an electron beam to make a full CRT TV picture. Yes, your old box would make up a full image within a split second by blasting electrons against a phosphor-coated screen, which made for a very rock 'n' roll way of generating frames.
Unless you've got some really high refresh rate eyeballs, you won't be able to see a CRT actively drawing horizontal lines. In fact, there's every chance that if you grab an old tube set right now and feed it a clean signal that matches its native resolution, you won't even see the distinctive black spaces that are dubbed "scanlines" today. That's because those gaps were more of a symptom rather than a feature, one that just so happened to add some extra pixel separation when gaming.
I own too many CRTs for my own good, ranging from a backbreaking 32-inch Aiwa set to an impossibly small 3.7-inch Sony Trinitron TV. Whether or not you can actually see distinct scanlines on each comes down to the resolution of a retro console, the cable type, and the display's own screen type, as all three can work to make the black space between rows less visible.
Standard Definition used to be, and still techniclly is, 480p, meaning 480 lines drawn horizontally using progressive scan. That's fancy speak for every one of those lines being drawn in order from top to bottom, but that means some trickery is required when using a 240p retro console like the NES, SNES or Sega Genesis.
The workaround involves the CRT filling its 480p screen with 240 rows of pixels by leaving every odd line blank. That results in a full image still being displayed on screen, but with distinctive black spaces between. That quirk is exactly what modern scanline effects attempt to replicate today, but there are other forces at play also messing with the look of raw pixels.
Behind the mask
When letting a CRT TV blast your eyeballs, scanlines likely won't be the first thing you see. If anything, you're more likely to notice the defined pixels that look like separate dots rather than a linear line of squares. What you're actually seeing is the image being drawn behind a metal plate, or "shadow mask", designed to guide electron beams directly to red, green, and blue phosphor dots.
Most consumer CRT TVs use a shadow mask, and it actually provides a distinct look that may distract you from scanlines altogether. The metal plate actually channels the electron beams into a triangle formation, or triad, that can reduce the visibility of direct, horizontal rows, portraying a more staggered pixel look.
Naturally, simply adding in horizontal black lines to retro console visuals on a modern LCD or OLED doesn't quite hit the same CRT notes as a shadow mask screen. Rather than getting that staggered triad color effect that adds pixel definition, you instead get a bolder horizontal effect that won't quite look like an old tube.
At the same time, not every CRT uses the same phosphor plate either. For instance, Sony Trinitron models are heralded for their Aperture Grille technology, which separates phosphors with tiny vertical wires. The idea is that the positioning will only allow the appropriate color through, rather than trying to block more light with a solid mask.
As a result, Trinitron CRT images are brighter, boast better color accuracy, and have enhanced sharpness thanks to the higher-pitch vertical dots. That is to say, there's less of a gap within each vertical stripe compared to using Shadow Mask triad clusters, and that in turn produces a pretty different look in terms of pixel separation.
Effectively, there's way more to making your classic games look like they're on a faux Cathode-Ray Tube. Scanlines are really just one part of a visual symphony that presents old sprites and textures the way their designers intended, rather than a bunch of scaled-up blocky pixels. Knowing that elements like CRT masking techniques, color bleeding, and phosphor positioning will provide different results will ultimately help you achieve the look you're looking for, whether that's based on something from memory or a collectively agreed gold standard.
Modern scanline techniques
It might feel like CRT TVs vanished from gaming setups aeons ago, but in reality, the screen type only properly retired in the late 2000s. That's the point where I noticed LCD panels properly take over the consumer market, and as someone who kept using old consoles with those displays, it became quickly apparent that they were missing a trick when it comes to classic visuals.
I was actually extremely late to the LCD part, having only picked up a budget 720p 28-inch LCD set in 2007 for my Xbox 360. It only took me a couple of months to realise that, while Bioshock looks phenomenal in "HD", consoles like my Sega Mega Drive looked a bit off even when using a clean RGB SCART input.
Naturally, the subpar upscaler in that supermarket brand LCD TV was committing more than just visual atrocities, but my immediate concerns were sparked by pixel separation. I really couldn't jam with Blaze in Streets of Rage looking like a bunch of blocks, and it kickstarted what would be a decade long quest to bring scanlines back to my setup.
I should note that for years, the only way to really inject scanlines back into my favorite games was by way of "modern" retro consoles. Yes, I did experiment with using standalone VGA scanline generators, like the SLG3000, but that was more designed for CRT arcade play rather than mimicking consumer sets. It wouldn't be until 2014 when the Hyperkin Retron 5 arrived on the scene that I'd first get a taste for scanline overlay effects as a feature baked into a system.
The approach with basic modern scanlines is pretty straightforward, as it simply requires adding an overlay of odd or even horizontal black lines over retro console images. That helps provide pixel separation and something that is reminiscent of old CRT TV visuals, and the Retron 5 was one of the first to provide that.
Since then, scanline overlays have matured, but basic implementations still come with the same caveats attached. Firstly, adding horizontal black lines alone isn't really enough to give proper CRT vibes, and scaling-related symptoms like uneven thickness and unadjustable intensity can be distracting. Darkening half the lines on screen also reduces overall image brightness, and depending on your screen, the remaining active pixels might look a bit too dim.
These are issues that still persist with systems like the Hyperkin Retron GX, and even scanlines with some layer of adjustability included in the likes of the Evercade Alpha still aren't super close to a real CRT. That's not to say we aren't seeing progress, though, as HDMI upscalers and FPGA consoles like the Analogue 3D are introducing more elaborate effects that leverage the latest screen tech and add more than just horizontal black lines.
Analogue's 4K N64 specifically proudly provides "display filters" rather than just basic scanlines. Rather than just slapping an overlay on top, the feature is a real-time processing option that weaves in accurate CRT effects that mimic every classic display type. The system includes everything from the look of a Sony Trinitron PVM and BVM sets to consumer-grade tube TVs that use Aperture Grille or Shadow Mask tech.
Better still, the Analogue 3D can now even leverage "advanced HDR" tricks to facilitate the same pixel brightness on new screens. That helps each phosphor look like it's actually firing from an electron gun rather than just being mimicked on an OLED or LCD, and the result is damn convincing.
Analogue isn't the only company going the extra mile with CRT effects, though, as I'm seeing more ways than ever to add more convincing scanlines and masking. The OSSC line doubler I use for most consoles has a wide array of dials for adding in scanlines in real time; the newer OSSC Pro can even enable Shadow Mask and Aperture Grille overlays.
OSSC | $111.99 at Amazon
GBS-C | $89.90 at Amazon
If you'd bring the Analogue 3D's advanced CRT filters to your entire setup, Retrotink also has you covered with its 5X Pro and 4K upscalers. They will make your bank account weep, but on top of providing FPGA-powered upscaling with motion-adaptive deinterlacing, they can also produce the same look as a Sony Trinitron or classic consumer set using similar processing techniques.
I'm fully aware I've been exclusively talking about hardware solutions, but modern emulators can also provide excellent scanline and CRT effects. Frontends like RetroArch include preset shaders for retro console cores, with CRT Royale being a prime example of a shader that can do more than just horizontal lines. Almost every emulation suite today at least has basic filters built-in, so it's worth messing around with those if you exclusively run your own ROMs on a retro handheld or PC.
Sneaking scanlines into your entire setup
I've been routinely asked whether there's a magic solution for adding scanlines to an entire setup. The answer is yes, as I've tested a doohickey that adds CRT scanline effects using HDMI, and it's not as atrocious as you'd think. Naturally, you'll have to use an upscaler or an adapter if you're using retro consoles with analogue output, but once you've got that sorted, it will inject adjustable effects into the pipeline before the image reaches your modern screen.
HDMI Scanline generator | $39.99 at Amazon
Of course, the effect produced by the standalone HDMI scanline generator still suffers from those classic caveats mentioned above. However, it includes on-board dials and switches for everything from scanline thickness to aspect ratio and even RGB color adjustment. The cherry on top is being able to switch between odd and even black lines, which will really help get you closer to the look you're after.
Your mileage with a standalone HDMI scanline generator will vary depending on your system of choice and screen. I do think it's worth a look if you can grab one for cheap, though, as it hooked my HDMI-modded N64 up with some much-needed pixel separation (the console's raw signal is pretty messy).
My hope is that by understanding why players rave about scanlines in retro games, you'll have an easier time deciding whether you care about the effect. Simply playing games raw without any overlayers or processing effects added in is completely valid no matter what those pesky enthusiasts shout at you online. That said, if you are craving CRT vibes but don't want to find a real tube set, you'll now know exactly how to go about transforming your modern display into a faux 20+ year old television set.
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