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    Brompton Technology
    Brompton Technology Ltd
    272 Gunnersbury Avenue
    Chiswick, London W4 5QB

    Elijah Ebo

    March 20, 2023

    Elijah joined Brompton in 2016 to grow our operations in the Asia-Pacific region. At the time, his focus was on managing panel manufacturers, but it became evident that Brompton’s market there included an important base of end users too. Today, as our Director of APAC Operations, Elijah leads a team of 20 people across UK, Shenzhen and Taiwan – including technical support specialists, field application engineers, account and general managers, and operations support. But as fast as our China operations are growing, Elijah keeps a very steady focus on quality – a value that has been with him since the early days of his career, and what ultimately led him to Brompton. 

    Soon after finishing his studies at the University of Surrey, Elijah landed a unique role at Vertu as their first hardware design engineer, scoped with developing the highest-quality phone on the market, regardless of cost. Elijah adds, “That freedom to design for excellence was something I wanted to find in any other job I did after that. It’s not often that you can set out to aim for the best performance, and I think that’s true of Brompton as well. Once we’ve figured out how to make something as inexpensively as we can, it’s about how good we can make it.”  

    Elijah’s first trip to Asia was in 1999 on a quest to find the perfect switch, which ultimately meant sitting down with manufacturers in Taiwan. He made frequent trips to Asia over the following years in subsequent roles and fell in love with the culture, so much so that he finally made Taiwan home in 2007, “That’s where I can think clearly, where I feel back at base,” he says. 

    Joining Brompton in 2016, Elijah brought with him many years’ experience in the APAC region and helped set up our first Shenzhen office in 2019. Just over a year later, the Shenzhen operations moved to bigger premises, doubling in size. This coincided with the release of several Brompton resources in Chinese language, including our configuration app, data sheets, and a website. Elijah adds, “It meant customers could do everything in a language they are comfortable with, that I think helped us grow. 

    Having travelled so extensively, where does he go to get away from it all? “It’s not a geographical thing for me, jogging basically is how I get away,” Elijah shares, adding, “Just finishing the jog in one piece is your main focus, and when you get back you can revisit issues with a fresh mind.” Elijah also chooses nature over cities, adding, “Getting away from technology and convenience I quite like. That’s where Taiwan is useful. A short drive away from the city you’ll find really quiet areas with no roads and no cars. 

    As for the road ahead, Elijah is big on Japan. He’s travelled there fairly frequently over the last few years and discovered that several companies have had their eyes on Brompton for some time. He concludes, “I never realised just how many people knew us and wanted to talk to us. I think there’s lots to come from Japan. 

    Chris Grandin

    December 15, 2022

    At the time Chris joined Brompton, in July 2019, he had clocked over 20 years’ experience within the demanding field of live events and installations. Much of that time with Gearhouse South Africa where he provided technical solutions for creative staging ideas and technical backup for events reaching audiences from a few hundred to millions. 

    Having worked with many LED processing products over those years, it was inevitable that he would come across Brompton’s Tessera processing system, which he recalls was “intuitive and easy to use”. When he set his sights on the UK, the name came up again, as Chris says, “Brompton came highly recommended and many of my friends and peers said it would be a good fit for me. 

    Barely 24 hours after touching down at Heathrow, he began his first day with Brompton, quickly settling in to help head up an expanding and busy technical support and training team. From a support perspective, the team is all about finding solutions to every challenge or query that comes their way. Chris expands: “We deal with technical challenges that our customers have presented to us, either by giving them the correct advice to resolve the problem or trying to simulate what they are doing. We’ll either give them a workaround or work with R&D and QA to find a solution. 

    It’s one of the things he’s known for: having a brain that never switches off. Sometimes he’s mapping solutions before even a problem is recognised. Chris recalls working on a commercial shoot for Honda where the idea was to create an animated film made entirely out of car headlights, but that was captured as a real event with 374 sets of lights acting like a massive LED screen. Driving home after a late pre-production meeting, he noticed something about his car’s lights: “I pulled into the driveway and in a reflection I could see that the headlights faded out, they didn’t stop emitting light the moment they switched off. I realised then that we couldn’t shoot the commercial in real time.

    As laser-focused as Chris is on identifying potential technical obstacles and finding their solutions, there’s an important people component to his role too – there’s the daily interactions with Brompton users and the relationship with his team members. He adds, “Although I’m technical, my primary focus is on people and making sure they have what they need to do the work they do. There’s too much to do so I have to rely on and trust my team.

    In and out of work, Chris enjoys technical challenges of all kinds. In his spare time he shops around for retro consoles and components for his computer projects. He also has an ever-growing collection of old and used desktop computers and laptops, rebuilding these for fortunate family members and friends.

    Cesar Caceres

    March 6, 2023

    Cesar is back at Brompton! It’s his second role at the company, this time as Product Lead, which he describes as being a product evangelist, adding: “The main part of my job is sharing the best information about what we do and my experience with video systems. I am passionate about technology that makes an impact, so doing this for Brompton just feels natural.

    Another title that fits is ‘technologist’, but ultimately for Cesar it’s about what makes users’ experiences better, and that’s what captivated him about Brompton originally, “I thought to myself, this is a company that’s listening to its industry and developing innovations that bring the best products to market. For me, that’s really important. Brompton is loyal to its technology, and is truthful about every message it makes public.

    In the years since he was last here, Cesar delved into media servers and extended reality. XR technology was very new then and he became an XR expert while based in the APAC region. He says it was a very privileged position to be in, recalling, “I went to different parts of Asia, supporting studios with this new technology. That gave me the opportunity to meet amazing people from all around the world.

    Equipped with this valuable experience, Cesar also had the opportunity to work in a VFX studio in Hong Kong where they built a new system. It was a career highlight and being involved in the process of buying an LED system gave him valuable first-hand experience: “I saw how it works from the customer point of view, and how we can make this process easier for Brompton customers.” He’s very clear that his new role is about conversations rather than sales pitches, explaining, “It’s just me as an engineer trying to help people get the best they can out of their video system.

    With the benefit of time, Cesar provides a great perspective on what has changed at Brompton and two things stand out: “The structure of the company has got much stronger, and the processors have many more features,” he says. “It’s very exciting in my position, because the more things we come up with, the more conversations we need to have!

    Originally a sound engineer who started out in recording studios to go into live music, Cesar was drawn into the world of video, which changed everything for him: “It gave me a lot of what I was looking for in life, a new motivation. The technology is growing really fast and new things are always coming up. I love the challenge.” Even in his time off, Cesar will spend hours building 3D worlds in Unreal Engine or exploring fantastic possibilities in AI. “Everything that’s technology related I want to learn how to use it,” he exclaims.

    He’s looking forward to seeing how the company will continue to evolve and alludes that this is happening already. With a twinkle in his eye, Cesar concludes, “With Brompton something even better is always coming.

    Neha Sharma

    November 15, 2022

    Neha joined Brompton as Marketing Manager in February 2021, which was a challenging but exhilarating time for the business. Virtual production was taking off and live events were just coming back. “It was a fantastic opportunity and it felt like a very good switch for me,” says Neha. Prior to Brompton, Neha was with a large printing company where she worked her way up from marketing co-ordinator to marketing manager. She’d also spent some time travelling in Australia and contracting for a variety of different firms in Sydney.

    Since joining Brompton, the business has been growing rapidly and the scope for Neha now is to build a team alongside an adapting brand, something that needs to be done swiftly, “We have to do that quickly because of how fast the brand is growing,” she affirms. Neha already has a digital marketing specialist working with her to build Brompton’s online presence and is exploring how the brand’s growth translates in a multitude of areas, even stand design. She expands, “Working with new stand contractors for upcoming trade shows is an opportunity to explore how we look as a brand that’s grown. Seeing those preliminary designs you can feel the change. And we’ll see that in every aspect: our website, brochure, social content… Now is definitely an exciting time.

    Neha works with many different people across the various Brompton departments and in different parts of the world. They include the CEO, engineers, developers, technical sales and support teams, digital specialists, writers, designers and web developers. Neha enjoys the sense of collaboration and having access to everyone who are each specialists in their area. She adds, “I love the culture. If you have questions, everyone is willing to answer them. And I think it’s important to have those kind of relationships internally – to be able to comfortably translate key messaging outwardly.” Similarly, Neha also finds Brompton customers easy to approach, adding, “We have exceptional testimonials from customers who use our technology. It almost does our marketing for us!

    Brompton operates in UK, Europe, America and Asia-Pacific, so Neha also has to consider how messaging translates across territories; what works in the UK for example may not apply in China. The way Neha manages this is by “making time, having conversations and asking questions”. She shares, “I had a recent conversation with our general manager in Asia to understand his team’s needs and the resources they have to take advantage of opportunities to be part of speaking panels.” Putting Brompton’s product managers and experts in front of audiences is another important part of Neha’s scope, she adds, “We have the experts and we look for great platforms where they can share their knowledge.

    The biggest challenge for Neha is time. “There’s so much to do!”, she says enthusiastically. She’s looking forward to continuing to grow a dedicated Brompton marketing team and the exciting opportunities ahead for working collaboratively and creatively to grow the Brompton brand. Neha concludes with a smile, “The best is yet to come.

    Recreating Reality: Eliminating Artefacts

    October 20, 2022

    Visual artefacts on an LED screen are like dirt on a window – they break the illusion and make you aware there is something between you and the scene. When viewing through a camera rather than directly with the eye, there are a whole new set of potential artefacts to worry about. We’ll try to give an overview here, and go into more detail in future blogs.

    First, you need to ensure each frame seen by the camera contains only one frame of content on the LED screen. If you have rolling bars, then the refresh of the LED screen and the refresh of the camera are not synchronised. If you have tearing or thick static bars, then you may be synchronised but out of phase. Genlock and phase adjustment are essential tools for any on-camera set up.

    If you are seeing thin, dark or light static lines on the screen, then it is likely that the time that the camera shutter is open is not an integer multiple of the PWM (pulse width modulation) cycle of the LED screen. Lighter lines are where the camera is seeing an extra partial PWM refresh and dark lines are where the camera is missing out on part of a PWM refresh. In the past, this was only solvable by choosing a camera shutter angle that didn’t show the effect – which meant some creative options were not available to the camera operator. However, Brompton Technology has developed a patented solution to this called ShutterSync, which allows the LED refresh timing to be tuned to suit the shutter angle of the camera rather than the other way around.

    Banding in gradients within the image is another form of artefact. Quite often in a virtual production setting we are running LED screens at a tiny fraction of their brightness capability – but that means lots of our bit depth is being wasted, which means there may not be enough left to get a smooth gradient. Choosing a panel with higher bit depth drivers is a good start – but run it at low enough brightness and the same issue is there. Brompton’s Operating Modes allow for different panel configurations that prioritise different performance characteristics – and one option is to have a mode (Studio Mode) for low brightness operation that turns down the driver current so you can utilise the full bit depth. In situations where you need more dynamic range without turning down the maximum brightness, then Brompton has two complementary tools available: Extended Bit Depth, which makes use of any spare performance of the driver chips to multiply up the PWM refresh, creating additional virtual bits, and Dark Magic, which applies spatial and temporal dithering. These tools are designed to be used together and that will usually yield best results.

    Other commonly encountered visual issues are moire and scan line artefacts. The LED processing does not have the answers here. Moire is interference patterns due to the grid of pixels on the camera sensor interacting with the grid of pixels on the LED screen, and is dealt with by selecting an appropriate pitch of LED for the distances in your shoot and/or keeping the LED out of sharp focus. Scan line artefacts are due to the electrical design of the panel – where one output from a driver chip is being reused to drive multiple LEDs. This keeps down the number of driver chips, which is more cost effective and necessary to make very fine pitches possible – but be wary of higher scan mux ratios (relatively low is 1:8 and very high would be 1:32) as it will have some performance trade-offs. Scan line artefacts typically show up when panning or tilting the camera across the LED screen, and so it is important to try any camera moves in a camera test with the exact panels you want to use.

    In the next few blogs in this series, we will go into more detail on how to recognise and eliminate common visual artefacts to ensure nothing breaks the illusion when recreating reality.

    Rob Fowler

    October 24, 2022

    Rob might not have been with Brompton on the official date of its origin – the day the first processor shipped – but he was very much part of that day. At the time, he worked for a rental company and helped take delivery of the shipment. It wasn’t long after that, in March 2013, that he joined and became Brompton’s first full-time employee.

    On joining, Rob briefly held the title ‘Partner Programme Manager’. “It was one of those, ‘What does that mean exactly?’” titles, Rob jokes, but the title could point in a few different directions – he was involved in the programme to bring other manufacturer and end-user partners on board, he provided technical support and conducted customer training. He was also doing a degree of business development even then, and as the company grew and his role evolved, that was the part of the business he found himself spending more and more time on – first as business development manager and then, from September 2019, as business development director. Over the years, our customer-facing team has grown to a much larger team, based worldwide, and includes Business Development, Technical Sales, Technical Support and Training.

    Rob has also witnessed how the business has grown to cover virtual production as well as live events, a trend that had started to gain momentum from 2018. “We saw significant amounts of equipment going to VP and we’d already decided to explore features we could develop to help users working on in-camera visual effects with LED” explains Rob. “When the pandemic hit, it made sense for Brompton to put not just some, but almost all our development efforts behind that for a period. But it took more than a year for live events to come back, and now they’ve really come back, which is great. In the meantime, ICVFX has grown to become a really important revenue stream in its own right, standing shoulder-to-shoulder with live events.” Rob adds, “We haven’t seen the full potential for ICVFX and we haven’t seen the full return of live events yet, but last year was a record year for Brompton, so it will be interesting to see how the balance develops, and there are other market areas that interest us too.

    For Rob, the great joys of working at Brompton are the teams that have been assembled in both support and development. “I knew the level of engineering in the Carallon team from having worked with some of them at Flying Pig Systems; I knew that they would be delivering great products. It’s a real pleasure to be able to represent incredible quality equipment.” He quips, “It’s so much more fun than working with rubbish stuff!” Concluding, “Likewise, it has been tremendously rewarding to be a part of building the team we have to support our fantastic customers and give a level of service that does justice to the ambitious projects they deliver week in and week out with our gear.

    Recreating Reality

    September 29, 2022

    Brompton Technology was launched, ten years ago, to address the LED processing needs of the live events space. But over the last few years the big growth area for us has been the use of LED screens as a replacement for green screen in virtual production. We are proud to have worked with some of the biggest names in film and television production and supported their amazing creativity. 

    Fundamentally, the challenge of virtual production is to create something that is entirely believable – where the viewer cannot tell whether it was shot in front of a real background or a virtual one. The clip below, created as a test by one of our partners, is wonderful demonstration of what is now possible. One of the images was shot on location and the other in a studio using a virtual background. Can you tell which one is which? 



    There are lots of elements to making a virtual background believable. For the LED processing it is about ensuring there are no visual artefacts that break the illusion and that the content is displayed as accurately as possible. We have learnt that when there is sufficient dynamic range to represent the scene realistically and the colours are as they should be, then the eye will believe it – and that is much more important than further increasing the resolution. In this, our unique Dynamic Calibration technology, which is the enabling technology for our implementation of HDR, is the key to maximising available dynamic range and colour accuracy at all brightness levels. 

    Over coming weeks we will be publishing a series of blogs looking in more detail at these key elements that go into recreating reality. 


    June 29, 2022
    The key to achieving superior accuracy and precision in dark imagery

    LED driver chips operate using linear PWM output. Unfortunately, our eyes (and cameras) sense brightness very differently, in a non-linear way with much more sensitivity to small changes at low brightness. As a result, reproducing accurate and detailed low-brightness imagery is one of the most difficult challenges for an LED panel.

    Many LED processing systems are simply unable to output low-brightness levels without various artefacts showing up, such as banding, colour shifts, speckle or ‘patchwork-quilt’ blockiness. Rather than fixing these problems, some of these LED processing systems implement a deliberate ‘fudge-up’ to artificially boost the brightness of dark parts of the image. Measurements have shown such systems can in some cases make dark parts of the image over ten times brighter than they should be. This has the benefit of simply ‘skipping over’ the problematic low-brightness levels, and to the casual observer can initially look ‘better’ because dark parts of the image appear brighter. However, in a professional environment, this creates two serious problems:

    First, the brightness levels being reproduced are extremely inaccurate, so the image will look very different to a reference monitor. This has the unfortunate effect of revealing detail that was meant to stay hidden, which can often include compression artefacts (such as blocks), camera or render noise (such as dither or speckle), and other artefacts which interfere with the image quality. This effect is exacerbated when using High Dynamic Range (HDR) content, which deliberately offers content creators the ability to accurately reproduce very low-brightness levels.

    Second, even in higher brightness parts of the image, the colour accuracy is adversely impacted, as any attempt to add a small amount of red, green or blue light to bright pixels will result in substantially more light being added than is intended. This introduces unpredictable colour shifts which are typically impossible to correct for. This effect is exacerbated when using a Wide Colour Gamut (WCG) such as Rec.2020 or ACEScg – as is also often employed for HDR content and for on-set environments.

    A key benefit of using LED panels for virtual production is the realistic lighting effects available. However, even the best LED panels have a comparatively low peak brightness compared to conventional lighting fixtures.” 

    Given both of these issues seriously reduce overall image quality and accuracy, Brompton Technology avoids these kind of ‘dark fudge-ups’, instead choosing to spend considerable time researching, testing and developing the ability to achieve superior low-end brightness accuracy. This originally led to our ‘Dark Magic’ feature, enabling previously unachievable low-brightness levels to be accurately reproduced in LED panels using the Brompton R2 receiver card. The further addition of ‘Studio Mode’ enables panels to be run at lower brightness levels while preserving PWM bit depth, which helps with the reproduction of low-brightness imagery, but does reduce the overall brightness the panels can achieve, making this technique less useful for HDR content.

    Performance at 1% brightness: Camera footage of 2000 Nits panels running at just 20 Nits.

    Brompton’s ongoing research has now led to the creation of a brand new feature – ‘Extended Bit Depth’ – to further improve the low-end performance of LED panels. In conjunction with ShutterSync (which ensures the LEDs are appropriately driven to avoid artefacts at any desired camera shutter angle), Extended Bit Depth enables panels to increase their PWM bit depth, depending on the video framerate and camera shutter angle in use. For example, a panel running at 24 fps with a camera shutter angle of 180° might offer an additional 2.3 bits of PWM precision, giving five times the number of achievable brightness levels at the low end, with 125 times the number of achievable colours. The result of this is that the panels can achieve an additional 2.3 stops of dynamic range at the low end – which is crucial when filming an LED screen displaying content such as dark, shadowy environments. Moreover, there is no reduction in the peak brightness of the panel, ensuring HDR content continues to be displayed to its full potential.

    Making the panels (and any lighting from them) appear much brighter on camera traditionally had the drawback of revealing artefacts in dark areas of the image due to the panels’ limited bit depth. Extended Bit Depth overcomes this issue, enabling higher apparent brightness lighting while maintaining background image quality. 

    A key benefit of using LED panels for virtual production is the realistic lighting effects available, which firmly anchor any foreground elements within the virtual environment. However, even the best LED panels have a comparatively low peak brightness compared to conventional lighting fixtures, so it’s a common scenario to want to achieve higher brightness output. While Extended Bit Depth doesn’t increase the overall brightness of the panels, it can effectively achieve a similar result by enabling the camera exposure to be substantially increased (typically by using a wider aperture or higher sensor gain). This has the benefit of making the panels (and any lighting from them) appear much brighter on camera, but traditionally had the drawback of revealing artefacts in dark areas of the image due to the panels’ limited bit depth. The additional precision and detail available in dark areas of the image when using Extended Bit Depth overcomes this issue, enabling higher apparent brightness lighting while maintaining background image quality.

    New camera sensors are offering ever-increasing numbers of stops of dynamic range. Ensuring that LED panels are able to keep up with this improvement is critical to maintaining the quality of the final output for virtual production and other applications using ‘in-camera’ capture of content displayed on LED screens.

    Extended Bit Depth is available as a free firmware update for all existing and new LED panels containing the Brompton R2 or R2+ receiver card, further extending their market-leading colour accuracy and image quality.

    What is going on with semiconductor supply?

    February 22, 2022
    What is going on with semiconductor supply?

    There is a lot in the news currently about car makers and other manufacturers not being able to get the parts they need to build their products. We talked to Brompton Technology CEO, Richard Mead, to ask what it is all about and whether it is affecting Brompton.

    What is the issue?

    There is significant disruption currently in the global supply chain – particularly for semiconductors (or microchips). Lead times (the time from order to delivery) are extremely long, more than 52 weeks for many parts, making it very difficult for product manufacturers to respond to changes in demand. In some cases parts are being discontinued at short notice forcing manufacturers to re-engineer products in a hurry.

    What is the underlying cause?

    There isn’t one single cause. It is a combination of multiple adverse factors, and the component manufacturers have referred to it as a “perfect storm”.

    Some of the factors have been building for a while. Trade disputes between the US and China and also between Japan and South Korea have constrained raw material supply, raised pricing and increased leadtimes.

    On top of this there have been several factory fires, earthquakes, and an extended drought in Taiwan (home of the world’s largest semiconductor manufacturer, TSMC) that have reduced capacity or slowed down the introduction of new capacity.

    The Covid19 pandemic is clearly a big factor, as it has caused factories to close for periods of time and supply chains to be interrupted during lockdowns. A lot of manufacturers work on a “just-in-time” basis, meaning they keep relatively little buffer stock of parts, and so a small disruption in supply can rapidly have a big impact on production and the knock-on effects can take a long time to work through.

    But it is not just about supply – it is also about demand. Over 2018 and 2019 the general trend was actually one of decreasing demand for semiconductors, and that will have slowed investment in building new capacity. Then the pandemic had the effect of rapidly increasing demand for consumer electronics, as people stuck in lockdowns redirected their discretionary spending away from travel and entertainment, and into home improvement and gadgets. At the same time “digital transformation” – the ongoing process of previously mechanical products becoming increasingly digital – is accelerating demand further. The big-name electronics manufacturers used their muscle to secure the supply they needed – but that further unbalanced the market and led to many other manufacturers being left high and dry. Other industries – such as automotive, medical and our own professional display solutions – were initially suppressed by the pandemic but demand has rebounded and now they find themselves fighting over the limited capacity that remains.

    What does the future hold?

    The market will find its way back into balance – but it will take a while. Most observers are expecting the supply situation to remain challenging throughout 2022.

    Some of the balance will come from increasing supply, and there is a lot in the news about the investment being made in new capacity by large players in the US and Asia. But it takes a very long time to build new semiconductor fabs – up to 5 years from start to finish – so there are no quick fixes there. And because of that long timescale, the semiconductor manufacturers are not necessarily willing to invest in new factories that make older technologies that might become obsolete before the factory has paid for itself – so the new factories will be for the latest technologies and therefore new types of chips, meaning the actual supply of the existing chips used in the products we have today may not increase much at all.

    In practical terms a lot of the balance will come from manufacturers re-engineering their products to design out older parts where supply is constrained and transition to newer parts with better supply. That process is always happening – but it is greatly accelerated by a shortage such as this. As large product manufacturers transition away from using older parts, that reduces the demand for those parts and starts to ease the supply constraints for everyone else.

    What does this mean for Brompton specifically?

    This is a global issue affecting all manufacturers big and small – and Brompton is also being affected. Right now we would like to be increasing our production to meet the high demand we are seeing from the fast-growing virtual production sector – but no manufacturers are able to ramp up at the moment and the focus is on maintaining production levels. Right now we do have a sizeable backlog, and we are working closely with our suppliers to improve the situation as quickly as possible. We appreciate the support and flexibility of our customers in coping with longer lead times than usual.

    Customers who are considering placing orders right now should take into account that delivery timescales are likely to be much longer than normal, but we expect the situation to improve as we move through the year.


    May 19, 2021

    If you have been following our social media and press releases, then you might be aware that we have just released a new version of our Tessera software, known as 3.2 to its friends. One of the key features of this new version is 3D LUT Import. What on earth is a 3D LUT and why should I care about it?

    Before we go into exactly what 3D LUTs are, it is worth looking at what a common or garden LUT is. LUT (pronounced ‘lut’) is an acronym that stands for Look Up Table. Within the context of image editing, film and video, a LUT is used to remap the input colour values of source pixels to new output values based on data contained within the LUT.

    In layman’s terms, a LUT can be considered as a kind of colour preset that can be applied to images or footage. But what does that mean in practical terms?
    LUTs are used for a variety of colour correction tasks, both technical and creative:

    Technical LUTs:

    • Display calibration: LUTs are used when calibrating monitors or other display devices for colour critical work such as editing or grading
    • Colour space conversion: LUTs that convert from different colour spaces, e.g. converting Rec 2020 to Rec 709
    • Camera LUTs: LUTs that are often created by the camera manufacturer to convert camera logarithmic formats that digital cinema cameras typically capture footage in (which look very washed out to the eye) into Rec 709 or Rec 2020

    Creative LUTs:

    LUTs can also be used creatively: for colour enhancement, creating monochrome or sepia effects, boosting shadows and highlights, or replicating the look of a particular film emulsion – the possibilities are endless.

    LUTs can also be both creative and technical, such as those created by DIT (digital imaging technicians) and stored into ‘LUT boxes’ connected to on-set monitors that combine a camera LUT with a creative LUT. This is helpful for giving some idea to the film crew on-set of what the camera is capturing might end up looking like when it has been graded in post-production.

    There are two major kinds of LUT: 1D and 3D.

    A 1D LUT on its own, when applied, can only change one input value to one output value. This means that it can only be used for changes in luminance such as gamma correction, contrast, brightness and black and white levels.

    ‘Fig 1: 1D LUT’

    However, commonly 3x 1D LUTs are used together: one for each colour channel. When the LUTs are applied to a source, the input red, green and blue values of each pixel, are mapped to new output values. The LUTs adjust the brightness of each of the red, blue and green channels independently of each other, depending on the values contained within the LUTs. This means they can only control gamma, brightness, contrast, black and white levels.


    ‘Fig 2: 3 x 1D LUTs’


    Whilst 1D LUTs are useful for many colour correction tasks such as overall colour balancing and gamma correction, they lack the precision required for more complex non-linear colour correction such as film stock emulation and colour grading.

    This where 3D LUTs come in. 3D LUTs map red, green and blue to three axes of a 3-dimensional cube. Colour values can be adjusted relative to each other, which allows any colour to be mapped to any other colour. This allows far more sophisticated colour correction, like changes in hue and saturation.

    A 1D LUT has a lookup table of values based on the bit depth. So, a 10-bit 1D LUT has 1024 values, and 3 1D LUTs have 3 x 1024 values – or 3072 values.

    Mapping the 10-bit colours in 3-dimensions means 1024 x 1024 x 1024 or over 1 billion values, clearly significantly bigger that the 1D LUT approach.

    This means that storing a 3D LUT in this way would mean a massive file size with implications for storage and performance. However, unlike the majority of 1D LUTs, 3D LUTs do not store an output value for each input value. They use a lattice of values, so a given input value exists at a point within the lattice.

    ‘Fig 3: An example of the contents of a 64x64x64 3D LUT.cube file. There are 64x64x64 = 262144 values for R, G and B

    ‘Fig 4: 17x17x17 3D LUT lattice’

    To calculate the output value, the value is interpolated – typically using trilinear or tetrahedral interpolation. The interpolation method used is very important to prevent visual artefacts. The size of the lattice and the bit depth of the 3D LUT determine the precision of the 3D LUT. Lattice sizes can be 17x17x17, 33 x 33 x 33 or 65 x 65 x 65 or higher, and bit depths can be 8-bit, 10-bit, 12-bit or 32- bit (floating point).

    3D LUTs are not only an extremely precise method of colour correction but also a very efficient one. 3D LUTs are used extensively in post-production in grading and finishing, display calibration, and on-set grading, as well as converting from camera log formats to Rec 709 or Rec 2020.

    We’re pleased to now be able to offer all those benefits of 3D LUTs with the ability to import them directly into your LED processor. We support any valid Adobe .cube file, and 3D LUTs can be pushed via IP control for more integrated workflows. This enables even more precise colour control for power users, and we hope it will be particularly useful for accurately recreating coloured “looks” and on-set grading on virtual production sets.

    Learn more on our page about 3D LUT Import.