Monitor Calibration Update
Okay, so I no longer NEED a new monitor, because I’ve got one – and my wallet is in Leighton Hospital Intensive Care Unit on the critical list..
What have you gone for Andy? Well if you remember, in my last post I was undecided between 24″ and 27″, Eizo or BenQ. But I was favoring the Eizo CS2420, on the grounds of cost, both in terms of monitor and calibration tool options.
But I got offered a sweet deal on a factory-fresh Eizo CS270 by John Willis at Calumet – so I got my desire for more screen real-estate fulfilled, while keeping the costs down by not having to buy a new calibrator.
But it still hurt to pay for it!
There are a few things to consider when it comes to monitor calibration, and they are mainly due to the physical attributes of the monitor itself.
In my previous post I did mention one of them – the most important one – the back light type.
CCFL and WCCFL – cold cathode fluorescent lamps, or LED.
CCFL & WCCFL (wide CCFL) used to be the common type of back light, but they are now less common, being replaced by LED for added colour reproduction, improved signal response time and reduced power consumption. Wide CCFL gave a noticeably greater colour reproduction range and slightly warmer colour temperature than CCFL – and my old monitor was fitted with WCCFL back lighting, hence I used to be able to do my monitor calibration to near 98% of AdobeRGB.
CCFL back lights have one major property – that of being ‘cool’ in colour, and LEDs commonly exhibit a slightly ‘warmer’ colour temperature.
But there’s LEDs – and there’s LEDs, and some are cooler than others, some are of fixed output and others are of a variable output.
The colour temperature of the backlighting gives the monitor a ‘native white point’.
The ‘brightness’ of the backlight is really the only true variable on a standard type of LCD display, and the inter-relationship between backlight brightness and colour temperature, and the size of the monitors CLUT (colour look-up table) can have a massive effect on the total number of colours that the monitor can display.
Industry-standard documentation by folk a lot cleverer than me has for years recommended the same calibration target settings as I have alluded to in previous blog posts:
White Point: D65 or 6500K
Brightness: 120 cdm² or candelas per square meter
This setup for ‘standard monitor calibration’ works extremely well, and has stood me in good stead for more years than I care to add up.
As I mentioned in my previous post, standard monitor calibration refers to a standard method of calibration, which can be thought of as ‘software calibration’, and I have done many print workshops where I have used this method to calibrate Eizo ColorEdge and NEC Spectraviews with great effect.
However, these more specialised colour management monitors have the added bonus of giving you a ‘hardware monitor calbration’ option.
To carry out a hardware monitor calibration on my new CS270 ColorEdge – or indeed any ColorEdge – we need to employ the Eizo ColorNavigator.
The start screen for ColorNavigator shows us some interesting items:
The recommended brightness value is 100 cdm² – not 120.
The recommended white point is D55 not D65.
Thank God the gamma value is the same!
Once the monitor calibration profile has been done we get a result screen of the physical profile:
Now before anyone gets their knickers in a knot over the brightness value discrepancy there’s a couple of things to bare in mind:
- This value is always slightly arbitrary and very much dependent on working/viewing conditions. The working environment should be somewhere between 32 and 64 lux or cdm² ambient – think Bat Cave! The ratio of ambient to monitor output should always remain at between 32:75/80 and 64:120/140 (ish) – in other words between 1:2 and 1:3 – see earlier post here.
- The difference between 100 and 120 cdm² is less than 1/4 stop in camera Ev terms – so not a lot.
What struck me as odd though was the white point setting of D55 or 5500K – that’s 1000K warmer than I’m used to. (yes- warmer – don’t let that temp slider in Lightroom cloud your thinking!).
Here’s the funny thing though; if I ‘software calibrate’ the CS270 using the ColorMunki software with the spectro plugged into the Mac instead of the monitor, I visually get the same result using D65/120cdm² as I do ‘hardware calibrating’ at D55 and 100cdm².
The same that is, until I look at the colour spaces of the two generated ICC profiles:
The coloured section is the ‘software calibration’ colour space, and the wire frame the ‘hardware calibrated’ Eizo custom space – click the image to view larger in a separate window.
The hardware calibration profile is somewhat larger and has a slightly better black point performance – this will allow the viewer to SEE just that little bit more tonality in the deepest of shadows, and those perennially awkward colours that sit in the Blue, Cyan, Green region.
It’s therefore quite obvious that monitor calibration via the hardware/ColorNavigator method on Eizo monitors does buy you that extra bit of visual acuity, so if you own an Eizo ColorEdge then it is the way to go for sure.
Having said that, the differences are small-ish so it’s not really worth getting terrifically evangelical over it.
But if you have the monitor then you should have the calibrator, and if said calibrator is ‘on the list’ of those supported by ColorNavigator then it’s a bit of a JDI – just do it.
You can find the list of supported calibrators here.
Eizo and their ColorNavigator are basically making a very effective ‘mash up’ of the two ISO standards 3664 and 12646 which call for D65 and D50 white points respectively.
Why did I go CHEAP ?
Apart from the fact that I don’t like spending money – the stuff is so bloody hard to come by – I didn’t want the top end Eizo in either 27″ or 24″.
With the ‘top end’ ColorEdge monitors you are paying for some things that I at least, have little or no use for:
- 3D CLUT – I’m a general sort of image maker who gets a bit ‘creative’ with my processing and printing. If I was into graphics and accurate repro of Pantone and the like, or I specialised in archival work for the V & A say, then super-accurate colour reproduction would be critical. The advantage of the 3D CLUT is that it allows a greater variety of SUBTLY different tones and hues to be SEEN and therefore it’s easier to VISUALLY check that they are maintained when shifting an image from one colour space to another – eg softproofing for print. I’m a wildlife and landscape photographer – I don’t NEED that facility because I don’t work in a world that requires a stringent 100% colour accuracy.
- Built-in Calibrator – I don’t need one ‘cos I’ve already got one!
- Built-in Self-Correction Sensor – I don’t need one of those either!
So if your photography work is like mine, then it’s worth hunting out a ‘zero hours’ CS270 if you fancy the extra screen real-estate, and you want to spend less than if buying its replacement – the CS2730. You won’t notice the extra 5 milliseconds slower response time, and the new CS2730 eats more power – but you do get a built-in carrying handle!