In these digital days your choice of monitor is key to achieving a smooth and accurate colour workflow. Most monitors are designed for general purpose office or home use. If you plan to process images, edit video or do design work on screen to any kind of professional standard you really need a monitor that has been designed from the ground up for that purpose. More and more monitor manufacturers are releasing screens into the photographic, video and design markets but many are little more than slightly tweaked mass market models. To get a monitor that you really can trust you have to delve a little deeper than the basic marketing blurb and specifications. You need to look at the quality of what you are going to get, and that can be hard to assess from a product description.

EIZO ColorEdge CG2420 CS2420

EIZO is a company that you may not have heard of. They aren’t a mass market manufacturer. But they have been market leaders in the narrow niche of colour accurate monitors for many years so I was eager to get two of their latest models to test.

ColorEdge CS2420

The EIZO ColorEdge CS2420 is the replacement for the very popular CS240 model. It’s aimed at the amateur or semi-professional photographer end of the market and has a price and feature set pitched at that level (at present it’s priced just below £500 ex VAT in the UK). It does enable customers on a budget to benefit from the two main selling points of the ColorEdge range – hardware calibration and the five year warranty. However, there are compromises that have been made to get the price down from its more expensive and fully featured stable mates, such as the CG248. You don’t get a shading hood, built-in calibrator and the quality control standards are a little looser.

ColorEdge CG2420

The EIZO ColorEdge CG2420 is the replacement for the mid-level CX241 and is pitched more squarely at professional photography, video editing and graphic design but sits below the company’s premium level products. Previously the CX sub-range was a clear indicator of a mid-level product but EIZO have chosen to bump the replacement to the CX241 up to the CG sub-range but the CG2420 is lower specced than the CG247, CG248 and other CG models. Basically you could say the CG2420 is aimed at pros with a tighter budget (currently it’s priced at just under £1000 ex VAT in the UK). It too lacks certain features when compared to the top of the range models but it does come with a shading hood and built-in calibrator, amongst other extra features over the CS2420.

I’m not going to list the full specs of each screen as you can get all that from the EIZO website. What my job depends on, and probably yours, is colour accuracy so that it what I will concentrate on.

First Impressions

Both monitors are significantly sleeker than many other ColorEdge models. The bezels are 37% slimmer according to the blurb, but they do still seem solid and well made. They aren’t as shiny and ‘designed’ as many other brands but you don’t want a monitor that shouts for attention on your desk you want one that lets you concentrate on the displayed image and the dark surround and matte finish helps with that. Both screens cover nearly all of the Adobe RGB (1998) colour gamut and the CG2420 also covers most of the DCI P3 digital cinema gamut.

The buttons and menu interface are clear, but you won’t be using them much as all the adjustment and calibration is done with the included ColorNavigator software. The anti-glare coating on both screens is very good with the CG2420 looking slightly sharper. Uniformity was also good with neither monitor showing any major signs of brightness or colour differences across the screen area. The CS2420 did, however, have thin slightly bright stripes down either vertical edge. Not enough to impact editing though as they were only a couple of millimetres deep. Both screens are measured in the factory and have digital uniformity correction but only the CG2420 has a guarantee of less than 3 delta E difference across the screen. Delta E is a measurement of colour difference. The shading hood supplied with the CG2420 was easy to fit and helps to reduce glare from ambient light.

ColorNavgator Calibration & Profiling

I connected both screens to my MacBook Pro and installed the latest version of EIZO’s ColorNavigator software. In addition to the Display Port, HDMI or DVI connection to each monitor you also have to connect a USB cable. The ColorNavigator software uses the USB connection to talk directly to the monitor and make all adjustments for you while it calibrates. The screens have a three USB ports you can plug other devices into, so you don’t end up being short of ports.

ColorNavigator is pretty easy to use, but it does have one big problem and that is the calibration presets, named Photography, Printing and Web Design. They aren’t really the best starting points. I always hit the button for Create a new target and set my own starting point. There are no right or wrong calibration settings but I find most users are happy with a brightness level of 100 cd/m2, a white point of D65 (6500K) and a gamma (tone) curve of 2.2. There are too many options to go into here but suffice to say you can calibrate a ColorEdge to pretty much any setting you could want. And the beautiful thing is that ColorNavgiator will do all the work and you don’t have to manually change any setting on the monitor.

EIZO ColorEdge CS2420

The CG2420 has a built-in colorimeter. The CS2420 doesn’t and so I used my X-Rite i1 Display Pro, but not with the X-Rite software of course. I calibrated and profiled the CS2420 first. The spec states the screen is warmed up in just three minutes but I did leave it on for twenty minutes just in case. The calibration and profiling process only takes a few minutes as the software displays many different colours and shades and the i1 Display measures the actual colour output. After calibrating the screen and creating an ICC profile ColorNavigator went on to validate the accuracy of the monitor.

The validation process displays and checks 134 colours and you get a nice little report at the end saying how accurate the monitor is. The report displays delta E values. Theoretically the average human observer can’t see a colour difference of less than 1 delta E, but it does depend on the colour and the observer. Most people can see a difference in grey of 0.5 delta E. The report said that the average delta E was 0.20, the maximum difference in the 134 colours was 0.83 and the difference in the white point was 0.18. So, basically, it was very accurate.

I opened my test image in Photoshop and concurred. The flesh tones were excellent, the greys very neutral, the shadow detail very good, the gradations smooth and the colours spot on. I’d very happily trust the monitor for image retouching.

EIZO ColorEdge CG2420

For the CG2420 I used the built-in sensor. The sensor used in the screen is a more basic one than EIZO have used in the more expensive CG models. It only measures red, green, blue, black and white and then updates the factory measurements stored in the monitor. The process was a lot quicker but visually the result was very good. The blacks were excellent. To properly cover the DCI P3 gamut the CG2420 can achieve deeper blacks with a much higher contrast ratio than the CS model – 1329:1 compared with 491:1. Compared to the CS2420 you could see that the shadow areas were deeper, richer and more neutral. The minimum black level for the CG was only 0.08 cd/m2 compared to 0.2 for the CS. Even lighter grey tones looked just a little more neutral. The panel that EIZO have used in the CG2420 is obviously a very good one, possibly one of the best I’ve seen.


The built-in calibration sensor in the CG2420 flips down from the top bezel.

But, and it’s a big but, because of the more basic sensor I couldn’t do a validation. So while I could see the monitor looked slightly better I couldn’t put any numbers on that impression. For many users that may not be a problem but what a customer is really buying with this level of monitor is the confidence that it is accurate and not being able to put a number on that accuracy dents that confidence. I did re-connect my i1 Display Pro and use that to do a validation but of course in measuring the validation with a different device to the one used for the calibration introduces another variable and inevitably some slight errors. The validation report had a maximum of 1.92 delta E, an average of 0.58 and a white difference of 1.92. Not disastrous figures but clearly not as good as the cheaper CS2420 model. So to remove the sensor as a variable I recalibrated the CG2420 using the i1 Display Pro and not the built-in sensor. This time I got a max of 0.67, an average of 0.15 and the white was 0.06. A very much better result.

Visually I couldn’t see much if any difference between the two calibrations but I had much more confidence in the one using the external colorimeter because I could put a proper number on things.


Without doubt the CS2420 is a worthy successor to the CS240 and if you are in the market for an entry level colour accurate display it should be at the top of a very short list. The calibration process is easy. ColorNavigator supports all the usual colorimeters and spectrophotometers and will deliver you a very accurate and pleasing to look at image.

The panel used in the CG2420 is one of the best I’ve ever seen with stunning levels of black depth and neutrality. But it is let down by the basic built-in sensor. If I had one I think I would use an external colorimeter and not rely on the built-in one and that would be a shame because the monitor can be set to auto-calibrate itself even if the computer is powered down. Viewed as an update to the CX241 though, it is a very big improvement as the CX model had a sensor that only calibrated monitor brightness – so you had to use an external sensor for calibration. At least with the CG2420 you have the option of using the basic sensor if you want to.

Most users would be more than happy with either model but those slightly more picky about their colours would see the benefit of the CG model, even with the caveat about the calibrator.