Each pixel on an OLED TV is an individual organic light-emitting diode. These require no backlight, so the screen can be much thinner. More importantly, when the pixels are off they are completely off, allowing much deeper blacks and more realistic lighting effects. Motion on screen tends to be smoother on OLED TVs.

QLED TVs are illuminated by LED backlights and a layer of microscopic semi-conducting crystals, which glow with particularly pure, bright colours. These “quantum dots” allow a much broader colour spectrum and higher peak brightness than OLEDs, making them easier to watch in bright rooms. They can also be viewed from a wider angle.

QLED was once associated with Samsung, but is now used extensively across the 4K TV market and prices are coming down quickly. OLED remains a premium choice. It’s rare to find a new OLED TV under £1,000.

Mini-LED is a new way of illuminating QLED screens, using much smaller diodes of less than 0.2mm. This begins to approach the microscopic size of OLED pixels and allows more control over the dynamic range. Because there are more of them, the image is several times brighter. It’s relatively new, but appears in many of this year’s best 4K televisions.

Mini-LED is not to be confused with micro-LED, a next generation technology that is so far only found in super-premium, oversized TVs costing over £50,000.

Nowadays, most TVs are 4K and that’s a good thing. 4K TVs have four times as many pixels as HD panels, leading to sharper picture quality on supported programming. Even on SD (standard definition) or HD (high definition) content, some 4K TVs effectively upscale, mimicking the effect.

If you’re considering upgrading from an HD TV but are unsure whether it’s worth it, there are a couple of things to consider. Firstly, what’s your TV viewing distance? If you’re too far away, you may not be able to appreciate the difference. Secondly, what content do you watch? While most streaming platforms now support 4K playback, terrestrial TV is HD at best and often still SD.

High dynamic range allows much finer gradations of light and darkness. On an old-fashioned TV, a scene set in a dark room with bright sunshine outside would have been a mess of white “bloom” and black “crush”. A HDR TV can reveal all the details within the scene.

There are four different HDR formats. HDR10 is the original. Netflix, Disney+, Amazon Prime and Apple TV all stream content in HDR10 and you should expect any 4K TV to support it.

Dolby Vision is more sophisticated, balancing the dynamic range frame by frame instead of scene by scene. The latest version, Dolby Vision IQ, also compensates for the lighting in the room the TV is in. Dolby is a proprietary brand that manufacturers have to sign up to. Most have.

HDR10+ was Samsung’s version of Dolby Vision (it doesn’t like signing up to other people’s tech), which has since been adopted by many other manufacturers.

HLG (hybrid log gamma) is the HDR format used by broadcasters like the BBC and Sky. Most modern TVs that support HDR10 will also support HLG.

Many TVs will now support all four of these formats. The software will detect which one is being used and switch between them automatically.