During Black Friday and the run up to Christmas , discounted TVs have been advertised with buzzwords such as 4K, UltraHD and HDR banded around as the latest and greatest thing – but is now the right time to buy one?

Having been burned by 3DTV and then annoyed by often rubbish smart TVs, you could be forgiven for thinking that 4K and HDR are the next big forgettable fad.

The difference here is that both technologies simply improve an existing experience. You don’t have to fight with an uncooperative system, wear special glasses or buy yet another version of the same movie you already own on VHS, DVD and Blu-ray.

Q&A What is 4K? Show 4K UHD video, also known as Ultra HD or simply 4K, is a format of video that has twice the number of vertical and horizontal lines, and four times the number of pixels as full high-definition video. 4K can therefore be significantly more detailed than HD and, particularly at large TV sizes, is seen as a upgrade in picture quality similar to the move from standard definition to HD. It is called 4K due to the horizontal screen display resolution being in the order of 4,000 pixels. For 16:9 widescreen video at 4K, the resolution is 3840 x 2160, compared to widescreen full HD, which has a resolution of 1920 x 1080.

The big driver for ultra HD has been the price of 4K TVs dropping to more reasonable levels from their £5,000-plus beginnings.

“It’s fair to say that most TVs on sale will be 4K-capable,” said Paolo Pescatore, vice president of multiplay and media at CCS Insight.

Good ultra HD TVs are available for well under £1,000, with even really great, big sets costing under £1,500 – such as Sony’s fantastic 55in Bravia XE9005. But while more pixels benefits large screens, it is HDR that has film and TV makers excited, as not only can it be made with four times the number of pixels, those pixels can be better.

HDR allows content creators to better display their vision on your small screen as they have done on the big screen, as well as do things that have not been possible with SDR formats.

However, HDR content doesn’t necessarily have to be 4K, and there are some HDR-capable TVs, typically smaller screened models, that are full HD, not ultra HD. Sony’s standard and slim PS4 consoles are capable of outputting HDR content, but not 4K, for instance.

Most top-end 4K TVs and even those in the under £1,000 bracket will support some form of HDR, with at least the HDR10 standard included.

Q&A What is HDR video? Show High dynamic range (HDR) video is that recorded and displayed with a wider range of colours than so called standard dynamic range (SDR).

HDR video therefore has a greater range of both contrast and colour than SDR, resulting in a more true-to-life picture and producing scenes with more "pop" or depth. HDR is usually combined with the increased resolution of 4K video producing greater detail and immersion. HDR video is different to HDR photography, where the latter is a technique that combines multiple exposures of a scene to create a single image with a greater dynamic range of luminosity, mimicking what is seen by the human eye. HDR video comes in several different standards or formats. HDR10 HDR10 is the most widely supported format available and controlled by the Consumer Technology Association (CTA). It is an open standard, using a 10-bit colour depth, and is backed by the big players, including Samsung and Sony, used by the Sony PlayStation 4 and Microsoft's Xbox One S and X. Both Netflix and Amazon Video also support HDR10. HDR10+ An update to HDR10 backed by Samsung and Amazon, HDR10+ adds metadata that aids brightness adjustment on a scene-by-scene or frame-by-frame basis. Dolby Vision Dolby Vision is a proprietary HDR format from the makers of Atmos. Vision uses a 12-bit colour depth and includes dynamic metadata, but has limited support in TVs and streaming content. Hybrid Log-Gamma Hybrid Log-Gamma (HLG) is an royalty-free HDR standard developed by the BBC and NHK. It requires systems capable of 10-bit colour depth, but is compatible with SDR displays. HLG is supported by some versions of traditional digital broadcast systems, as well as BBC iPlayer, Freeview Play and Google's YouTube streaming services.

Getting content

Streaming services such as Netflix and Amazon Video, as well as broadcasters such as Sky and BT, have made accessing 4K and, to a lesser extent, HDR content easier than ever.

Almost all 4K and HDR TVs will come with some form of smart TV platform, which support various streaming apps. If they’re terrible, or don’t support the right services, smart TV boxes or dongles are also available, with several including Amazon’s Fire TV HDR and Google’s Chromecast Ultra costing under £70.

The biggest change in 2017 was the size of the libraries of TV shows and movies available. New TV shows and movies are more likely to be available in 4K and HDR across the board.

Almost all of Netflix’s original shows are available in at least 4K, with many in HDR too. Highlights include Godless, Narcos and Marco Polo, all of which look spectacular on the right screen.

Photograph: Alex Wong/Getty Images

Amazon’s roster of 4K and HDR content is similarly focused on its original productions. Even the Grand Tour looks stunning despite it just being three ageing Brits driving around.

Both Google Play and Apple’s iTunes offer 4K movies on an ad hoc basis too, with smaller on-demand services beginning to offer more.

“There’s a lot of misconception at the point of sale, with buyers expecting all the broadcast services to be in 4K, which is not yet the case,” said Pescatore. “The web guys such as Amazon and Netflix have certainly lead the way on both 4K and HDR so far. But BT and Sky are catching up, leading with sport in 4K.”

Both Sky’s Q 2TB box and BT’s TV offer the Premier League in 4K and with Dolby Atmos, which looks and sounds almost like being pitchside with the right gear. Sky also offers Formula 1 and cricket in 4K, both of which benefit from the increased detail, plus a range of movies and TV shows on demand in 4K.

But other broadcasters have lagged behind, primarily due to the cost of production and distribution in 4K with limited spectrum across which to transmit the data-heavy signal.

“We’ve seen traditional broadcasters commit to showing the big sporting events in 4K in 2018, including the Winter Olympics, Wimbledon and the World Cup,” said Pescatore. “2018 will be a big year for the likes of the BBC and ITV, driving users to IP TV with their catchup services.”

While 2018 will be the year 4K hits the big time, the same cannot be said for HDR, says Pescatore.

“The web and telecoms companies are leading way in HDR, and it will be live sport that will drive adoption, with BT Sport well placed with a tech-focused offering of 4K, HDR and Atmos,” said Pescatore.

Of the competing HDR standards, the open HDR10 format has been the only outright leader so far, becoming the default to which content and TVs fall back on for compatibility. But issues around standards, support from electronics manufacturers, the cost of production and difficulties and cost of broadcast of the improved content will hold HDR back in 2018.

“When you buy a TV it may seem like the latest and greatest, but the HDR landscape is still a minefield of formats that mean you have to have the right TV with the right box and right content,” said Pescatore.