Epson and what is PRO-UHD?
During Epson’s recent launch of their PRO-UHD projector range held in Sydney, one of the points the Japanese manufacturer wanted to drive home was that resolution isn’t everything when it comes to Ultra High Definition standard.
Of course, it’s easy to dismiss such statements from a manufacturer who isn’t producing true 4K projectors. However, when you look at all the Ultra HD standard has to offer, there’s more to this statement than what appears at first glance.
While I’m not about to trade in my native 4K projector any time soon, Epson does have a point. And a rather good one at that.
As pixel counts increase, the actual size of the pixels become progressively smaller. To release all of the glorious detail that higher resolutions have to offer, you need to either increase the screen size or sit closer, or better yet, both.
The creative geniuses behind the UHD Standard knew this only too well, realising resolution alone wouldn’t be enough. Hence the introduction of HDR (High Dynamic Range) and WCG (Wide Colour Gamut) with the Ultra HD Standard.
Unlike an increased resolution, the benefits of HDR and WCG are apparent regardless of screen size. Hence the creation of HDR10, HDR10+, HLG and Dolby Vision. While the technological approaches vary, the goal of these competing technologies is the same which is to create a picture with a higher dynamic range and a broader range of colours.
Enter Epson’s new 4K PRO-UHD technology, which is an umbrella term built around three aspects: High Brightness, Full DCI-P3 Colour gamut and High Detail.
Of course, these aspects are also the fundamentals of the UHD specification. However, colour reproduction and brightness are the Achilles heel of many home theatre projectors, regardless of price-point.
Each of the projectors in the 4K PRO-UHD range has three dedicated processors for 4K Image Enhancement, Image Processing and HDR Processing. Having a dedicated processor for each of these areas allows the projector to always perform to the very best of its ability, without the need to share resources.
4K Image Enhancement
At its heart, Epson’s 4K Image Enhancement utilises pixel shifting technology to produce ‘emulated 4K’, with Epson projectors having a true native resolution of 1080p.
4K enhancement works by diagonally moving the output of the 1080p panel between two different positions, thereby ‘doubling’ the onscreen pixel count. Pixel shifting creates a little over 4 million pixels, double the pixel count of 1080p, but only half the pixel count of native 4K.
While it’s correct that pixel shifting doesn’t offer the last word in image detail, they can do an outstanding job with a very noticeable improvement over standard 1080p.
By way of a separate processor and thereby more ‘horsepower’ Epson has been able to take their pixel shifting technology a step further. With a dedicated processor, each pixel can stay in position a fraction longer and make its transition to the new position faster than previously possible.
The new iteration of pixel shifting makes images sharper than previous iterations, by reducing the inherent ‘motion-blur’ which is a by-product of shifting pixels at rapid frequencies.
HDR Processing and Brightness
Creating compelling HDR images requires a high luminance display device, and this is undoubtedly the most significant challenge faced by today’s projectors.
The 4K UHD standard is based almost exclusively around LED/LCD and OLED televisions, only the most expensive of which is now reaching 2,500 nits.
Granted, image brightness is an area which has improved significantly over the years, with most home theatre projectors being more than capable of meeting the luminance demands of HD viewing in a light controlled room.
However, with the advent of HDR and peak brightness demands of 4,000+ nits, today’s projectors have once again fallen well short of the peak luminance demands of today’s viewing material. The current challenge for projectors is producing as many lumens (brightness as possible).
Epson has quoted its PRO-UHD range of projectors as being capable of producing 2,600 ANSI lumens. This figure exceeds the light output of many laser-based projectors on the market today, which is exceptional, especially considering both the TW8400 and TW9400(W) use lamps with a quoted replacement cost of $120.00.
With three-chip LCD technology being able to produce the same level of white light output (2,600 ANSI lumens of WLO) and coloured light output (2,600 ANSI lumens CLO) from their range of PRO-UHD projectors. In addition to helping meet the demands of HDR material, it also helps in reproducing a broader range of colours.
While both the TW8400 and TW9400 offer high levels of luminance for home theatre projectors, they still fall short of 1,000 let alone 4,000 nits. For this reason, Epson’s PRO-UHD projectors have sixteen user selectable levels of tone mapping, which are accessible directly from the remote control.
If you’re not familiar with how Tone Mapping works, it’s how a display remaps the steps between its peak luminance and the peak luminance of the incoming signal. For instance, if a display (projector or TV) is capable of a peak luminance of 700 nits, but the incoming signal is mastered on a display with a peak luminance of 1,000 nits, the extra steps of luminance need to be remapped by the display.
There are several methods used to do this, one option being to clip any information above 700 nits, which effectively discards the spectral highlights found in the 700-1,000 nits range. While some clipping is unavoidable, another approach is to create a softer roll off of the PQ curve, remapping as many values as possible before the display clips.
If you haven’t already guessed, there’s no ‘one size fits all’ approach tone mapping. Much of it depends on your display and the incoming signal; the latter of which can be a moving target! Added to this challenge is that with the far finer steps of low-level luminance contained within the HDR signal, it’s now more critical than ever that ambient light is controlled within the viewing environment.
Recognising both the challenges faced by lower luminance display devices and less than ideal viewing environments, the PRO-UHD tone mapping offers sixteen steps ranging from 100 to 10,000 nits.
All of these settings are accessible by the user directly from the remote with the dedicated HDR button. The HDR button provides more tech-savvy users with the option to adjust the level of tone mapping on the fly.
Via the HDR button, the user can select several different preset viewing environments, enabling both novice and more advanced users to adjust the overall brightness of the picture based on the viewing environment.
Wider Colour Gamut
Another big drawcard often swept under the mat in favour of higher resolution is UHD’s expanded colour gamut. The move from standard definition to high definition heralded a move from the Rec. 601 colour gamut used in PAL to the now commonly used Rec. 709 High Definition colour gamut.
Although the move to Rec. 709 was a bigger one for our US cousins, as it brought a noticeable improvement over NTSC, the benefits here were marginal. This is because Rec. 601 and Rec. 709 were similar in terms of the position of their primary colours.
The move to 4K Ultra HD brings with it yet another change in colour gamut to DCI- P3, which is often abbreviated ‘P3.’ Although P3 may be a newer standard for the home, it’s been in use for some time in digital film, so there’s more than a strong chance you’ve already seen this new colour gamut in at your local theatre.
Unlike the shift from Rec. 601 to Rec. 709, the change from Rec. 709 to DCI-P3 is a significant one, with the much broader colour gamut immediately noticeable. Take a quick look at the Extreme Wide Gamut 100% of DCI-P3 diagram, and you’ll see what we mean.
While DCI-P3 may be the defacto format of Ultra HD, even if you own a 4K projector, there’s a good chance you haven’t seen it yet in its full glory. This is because most of the home theatre projectors commonly available haven’t been able to produce the full range of colours offered by DCI-P3.
The 2019 crop of more affordable home cinema projectors is amongst the first capable of producing the full range of colour which DCI-P3 has to offer. This range of colour reproduction previously being the purview of more expensive projectors, many of which are still not capable of reproducing a full P3 colour gamut.
Epson has been able to achieve the full DCI-P3 colour gamut, in their PRO-UHD range of home cinema projectors by virtue of their increased brightness and dichroic mirrors, which have been finely tuned to produce broader primaries.
In addition to offering DCI-P3 colour reproduction, Epson’s PRO-UHD projectors are said to provide reasonably accurate ‘out of the box’ grayscale accuracy. All of the PRO-UHD are, however, ISF Certified projectors, which means they can be calibrated for an even higher level of accuracy.
In this regard, the PRO-UHD offers greyscale and multi-point gamma control which are said to provide more granular control than ever before, in addition to a six-point colour management system.
Of course, we’re keen to test the veracity of these claims. To that end, we have the Epson TW9400 in now for both review and calibration, so stay tuned!
For more information visit Epson.
As the owner of Adelaide based ‘Clarity Audio & Video Calibration’, Tony is a certified ISF Calibrator. Tony is an accomplished Audio-Visual reviewer specialising in theatre and visual products.