CRT Filters And Retro PC Games


A common point when it comes to retro gaming on modern hardware has been the use of filters to make it look like you’re playing a game on a 90’s CRT. Usually this is a thing with console games, and until now I never thought to try it with PC games. Old monitors were technically CRTs too, just a different kind.

Over the last couple days I’ve been testing a few different old school filters with either old PC games or new PC games that are supposed to look like old games. The results have varied but I think they’re very much worth sharing.

CRT or scanline filters for retro games running on today’s hardware are definitely not uncommon but still haven’t quite become a universal thing. Most emulators feature them, and we’ve even reached a point where a lot of the time an official re-release of a pixelated classic will feature some kind of scanline option. I switch back and forth between them and clean pixels, but I like having the option. It mitigates the glaring visual flaws of old games and makes them look closer to how they did in the 80’s and 90’s.

There are still more places I’d like to have that option though. Nintendo should have it for Wii U Virtual Console games since you’re forced to run them in 480p. Right now the best thing you can do is play them on the GamePad’s 480p scanlined screen. Sony should allow the feature for PSOne and PS2 Classics on the PS3. More importantly though, all these indie developers making games with retro graphics should include CRT filters. The only one I can think of that does is the old demo for the recently-released Castle in the Darkness. That’s why I started trying to mod the filter into some of these games with varying results.

A point some might have however is that the image on a PC CRT monitor looks very different from that of a CRT television, and that’s correct. CRT monitors display various resolutions with generally cleaner images, so it’s not quite right to have an old PC game looking like it’s running on a Zenith. That said, both types of displays come in various shapes and sizes that produce different kinds of scanlines. These filters I tried out offer a lot of options for adjustment to fit that diversity.

What got me started doing this was a set of screenshots someone posted where they’d applied a CRT filter to DOOM and I thought it looked amazing. Someone said it reminded them of the SEGA CD version of the game. The simplest method to get scanlines in any DOOM engine game is to run it through Chocolate Doom with the “-scanline” parameter applied through a shortcut to the exe. It actually produces scanlines that I think look very much like a 90’s monitor rather than a TV. Combined with the way Chocolate Doom preserves (but upscales) a game’s original resolution, you get a picture that’s very faithful to the past but looks good on today’s displays. The only downside is you need at least 1200 pixels of height on your display to use the parameter. The method I chose to use was GeDoSaTo’s “Advanced CRT” setting through ZDoom which creates more of a TV effect. The only major downside here is it makes small text basically unreadable.

I tried CRT filters on a few 2D pixelated indie games but could only get one to work on Shovel Knight. This game prides itself on staying very true to the NES hardware, so scanlines only seem right for it, and in my opinion they complete the look of the game. This is of course if you aren’t already playing the 3DS version or the Wii U version on the GamePad screen. I used a version of SweetFx with a CRT mod somebody cooked up on Shovel Knight’s Steam forum. I really wanted to try this on Oniken but couldn’t figure out how. In the future I’ll see if I can do the same for games like Cave Story and La-Mulana.

One game I was glad to see the same SweetFx implementation work on is Sky Rogue. If you aren’t familiar, this is a 3D game built with flat-shaded polygons like the original Star Fox or the first Virtua Fighter. Seeing it like this brought me a little bit closer to that 1995 fighter simulator feel Sky Rogue is trying to capture. I really do hope the game eventually includes this as an official graphics option. I hope the same for upcoming games like Steel AssaultStrafe, and Starr Mazer.

Another thing I messed with but couldn’t quite get working is a SweetFx implementation called LeiFx. It’s specifically supposed to recreate a look produced by the old Voodoo graphics accelerators, altering the color balance and adding scanlines to 3D PC games from the late 90’s. I tried it on a few games like Thief and Deus Ex but couldn’t get it to work. I think it’s meant mainly for Quake engine games.

As I go through more old school games in my seemingly never-ending backlog I’ll surely keep trying this where it makes sense in the future.


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3 thoughts on “CRT Filters And Retro PC Games

  1. This will be a great feature if modern consoles will have it. It will certainly add an authentic retro feel to old games, kind of drawing you virtually back in time and remember how it felt like while playing electronic games when you were a kid.

  2. Jonathan says:

    Not one of the CRT monitors I had in the 90s actually had scanlines. Different gamuts to TFT, sure, and warping when the glass wasn’t perfectly flat, and various other graphic aberrations, but scanlines were something I only ever saw on TVs with consoles, never PC. The closest I saw was some microscopic horizontal lines on some Iiyama monitors, but there was only one or two of those on the display (iirc these were 17″ CRTs, they belonged to a flatmate of mine in University).

    • RedSwirl says:

      You’re right. I mentioned that a bit. The CRT filter in Chocolate Doom doesn’t actually have any scanlines but tries to recreate the effect of CRT monitors. The thing is though, that a lot of the games I try the filter with are games that are evocative of old console games. Plus, the PC I play many of them with is hooked up to a TV while I play with a controller. It’s a weird combination of hardware when you think about it.

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