Samsung UD970 Review

From ColorWiki

Jump to: navigation, search

CHROMiX had the rare opportunity to test a couple of 4K displays by Samsung. This Korean manufacturer is not normally known for the kind of high-end quality needed for color-critical work, but their latest addition is worthy of consideration if you are in the market for a 4K display.

The Samsung UD970
The following tests were run at 100 cd/m2, 6500 K, Gamma 2.2 unless otherwise noted.

Contents

4K

Comparing UHD resolution with other resolutions

The 4K Ultra High resolution provides a whopping 4 times as much screen resolution as the typical HD dimensions which are 1920x1080. When run at its native resolution, you can fit a lot more detail on the screen. The first issue you might have is finding a graphics card capable of displaying at the 4K resolution of 3840 x 2160. This is worth checking out before plunking down the money for one of these big displays. Even relatively recent Macs are not equipped to display 4K resolution. On Windows, check your video card to see if it can handle this resolution.

Also if you’re just getting into the 4K phenomena, bigger is not always better. The appearance of everything on the screen may be smaller than what you are used to. This is normal. The purpose of a 4K display is to be able to present some 8 million pixels on a single display, so you don't have to straddle the image over two displays for example. This is very handy for people viewing 4K video camera files, or photographers working with large, detailed images. On the other hand, if you are just going to use it for checking your email, you might find the text to be small and hard to read. Choose your equipment wisely.

Color Gamut

UD970 gamut compared to AdobeRGB

The UHD970 reproduces almost all of the gamut of AdobeRGB. This is a newer color-critical essential for those who want to accurately preview highly saturated images. This kind of display is capable of reproducing much stronger greens, yellows and reds than what you expect from the average display off the shelf. For that reason a wide-gamut display like this is very useful for viewing a “soft-proof” of what an image will look like when it gets printed. Modern inkjets are capable of broader ranges of colors, so a display like this is all the more necessary if you print to a modern inkjet or work with saturated colors a lot.

The ColorThink Pro gamut volume of this display at its native gamut is:

1,141,000 cubic Lab values

measured using an X-Rite i1Display Pro colorimeter.

Uniformity

Click thumbnail to see the uniformity layout.

This is the first place I looked when trying to find something wrong with this Samsung monitor. I expect a second-tier display to show some unequal reproduction of color in different parts of the screen. This display has fantastic uniformity! We wanted to make sure this wasn’t just a fluke, so we asked for a second display from Samsung. The second display also has fantastic uniformity. To put numbers on this, we usually expect a top of the line display to have uniformity of less than 3.0 delta E 1 between any two points on the screen. The Samsung’s came in at 1.57 between the lower left corner and the upper right corner.

As a display ages, the uniformity is likely to change and get worse over time. The Samsung calibration software has a procedure whereby the user can measure the display using any of the common measurement devices, and not only view the state of the uniformity but also apply the result to the display. If this feature works as it appears to, this would provide an excellent means of correcting uniformity as the display ages.

Evenness

While the bulk of the screen is uniform, it is natural to visually see some fall off of evenness toward the edges of the screen. The Samsung has a darker gradient starting from about 2 inches from the right side, and another starting from about 1.5 inches from the left. This might seem like a large amount to those used to working on a smaller display. The entire center portion of the display is visually very even all the way across.

Brightness

The maximum brightness of the display is about 230 cd/m2. For the kind of color-critical work this display was designed for, it will usually be run at about 100 - 120cd/m2. This is plenty enough brightness for normal circumstances.

Black level

Using the Samsung software to calibrate, this display reports a black point of .3 cd/m2. An Eizo or an NEC will get down to a very dark .16 using the same measuring instrument. The Samsung software is limited to one digit in its report, so we don’t know if this is actually rounded down from 3.4 or if it is rounded up from 2.6. The lower the number, the better the display will be since you generally want a display’s black to be as black as it can be. This makes a difference to the ability to reproduce shadow detail, and to the overall contrast ratio. If the display can produce a darker black, then it will have a greater contrast. A black point of .3 is actually rather high, and this is one of the factors that separates this display from a more higher-end display such as an Eizo. At full brightness (230), the black level is .7 cd/m2 - which is quite bright for a black. The “brightness” of the black will also mean that this display will not be able to offer you as much contrast when it’s being used in low light environments. In a workplace where ambient light is brighter, this display should work fine.

Calibration software

Main window of the Natural Color Expert app

To make full use of the 10-bit interval calibration resolution, Samsung provides their own calibration software. The Natural Color Expert (NCE) app will interact with the internal graphics to calibrate and profile the display. The NCE app has all the features you would normally need to make a quality calibration of a color-critical display. You can adjust the precise level of brightness, white point temperature, gamma, black level, etc. you desire. You can also calibrate to a specific color gamut, such as BT.709, sRGB or AdobeRGB.

One puzzling issue was in the calibration result. When compared to the aim points that the calibration was trying to hit, most of the metrics were very close to the targeted values. One exception was gamma. Gamma is a setting that affects the appearance of how bright or dark the mid-ranges look. The recommended standard is 2.2. However, the result of calibrating to a gamma target of 2.2 is a resulting target of 1.8 or 1.9. Regardless of where the gamma value is set, the calibration result ends up being 30 or 40 points lower. I’m not sure if this is a bug in the software or not. In practical usage, this issue would not be a problem, since the gamma value is inconsequential when viewing images in ICC-aware apps like Photoshop or Lightroom. The gamma value will not affect the appearance of images at all in these apps.

The NCE software creates a small matrix profile of about 3 KB. It is ICC version 2 compliant. The software has no options for making version 4 profiles, or Look Up Table profiles or changing the number of patches used to create the profile. The software does not appear to offer a way to click back to a previous saved calibration state. This is a handy feature that Eizo and NEC provide for their displays. It’s convenient to be able to quickly switch from sRGB to AdobeRGB, or to a brighter calibration state temporarily.

Other items of interest


All in all an impressive display. For $1300, you can get a color-critical 4K display that has a saturated gamut of AdobeRGB, has a IPS panel giving you wide viewing angles, the ability to calibrate your display with your favorite colorimeter, and solid-as-a-rock uniformity across the screen. As long as high contrast is not a vital concern to you, this could fit your budget very nicely.


Official Specs

Footnotes

1 See the glossary for a definition of deltaE.


October 5, 2015
Patrick Herold
CHROMiX, Inc.

Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox