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the Discus colorimeter from BasicolorThe basICColor Discus

Monitor and projector calibration, with ambient light measurement

We've looked at a number of monitor calibration and profiling solutions in the past, all have their strengths and weaknesses, but last year a new 'no holds barred' solution was announced by German company basICColor.

The Discus has been designed to meet the demanding requirements of high end users in press and proofing, and to provide calibration of the newer wider gamut monitors, that can be problematic with some existing older products.

Keith has tried the Discus on both our older Apple Cinema Display and an NEC SpectraView Reference 271 [review] wide gamut 27" monitor, kindly loaned to us by NEC UK. This was arranged by the UK supplier of the Discus, Native Digital who also loaned us the Discus to try out...

The examples shown here are using Apple Macs, but the software generally works in the same way on Windows machines.

... or try at Adorama

Monitor Profiling

I've looked at numerous monitor calibration and profiling products over the years, and this one is firmly positioned towards the top of the market.

basICColor, the company behind the device, is known for its colour management products aimed at the higher end of the market, and at around £800 for just the device itself, it's perhaps beyond what I'd consider appropriate for my own work as a professional photographer.

However, in the market it's produced for, paying several thousand pounds for a monitor and several thousand for printer driver software is not uncommon...

What do you get

The Discus is a solid bit of kit - literally. It weighed in at ~340g (12oz.) and the electronics are encased in a solid aluminium shell.

There is a comprehensive reference manual provided.

It comes with a 270g counterweight, which I'm assured is a real ice hockey puck (I've never seen one before)

Move your mouse over the image to see the measurement side of the device.

That's also a real tape measure as a strap. The strap is detachable if you were using the tripod mounting bush at the bottom (standard 3/8" thread with 1/4" adapter) for projector profiling and measuring ambient light.

Even the angled sides of the device are to assist in assessing the lateral lighting of your measurement area. This from the manual:

  • 'In an "open" environment (e.g. at the control panel in the pressroom) you would want to know about the influence of the lateral ambient light. In order to facilitate the relevant measurements the housing is fitted with two 45° bevels and the edge of the housing is rectangular to the bottom. Thus you're able to measure under 5 different angles without any auxiliary means: Paper plane / Paper plain ± 45° / Paper plain ± 90°. In an ideal environment there will only be changes in the illuminance level, not in color.'

Specifications (from basICColor)

Features

Software

The basICColor software is not currently included with the device, so I had to download a demo license and install it on the desktop Mac Pro I was using for testing (V4.2.4 tested). The software is tied to the computer you set it up on. As of writing the Discus is also supported by NEC SpectraView Profiler (you will need to get the version that supports the Discus).

For monitor profiling I'd slightly tilt the monitor back to get good contact. The software guidelines suggest performing any measurements in the dark.

different measuring devicesThe picture shows a rather cluttered desk, since the 23"Apple monitor is just behind the NEC one.

The small monitor to the right is an old one I normally use for palettes and the like.

It's quite old, but the Discus and basICColor were able to get it to a very respectable state - noticeably better than any previous attempts.

The software supports several different measuring devices.

If you look below the monitor on the desk, you can see an i1 Pro spectrophotometer and a Spyder3 colorimeter, both of which I use regularly.

The software handles any calibration that the device might need.

selecting an i1 pro with the software

Below, I've selected the NEC monitor, since the Discus option allows you to specify the type of device you are measuring (right).

The Discus has it's own calibration setting that you are prompted to select before proceeding.

The measurement unit has a rotating disk, that switches between calibration and measurement positions.

Moving from calibration position to measuring (move mouse over image)

I'll not go into all the measurement options for basICColor here, other than show the range of tonal response curves available as options when calibrating.

There are a lot of brightness and colour related options available.

I normally work at D65, gamma 2.2 and a brightness of 110 cd/m2 with the Apple monitor - this gives a bright enough image for my work environment and good enough soft proofing and comparison when using my PDV-3e lighting stand.

  • Setting the NEC wide gamut monitor to L* may be recommended, but the effect on coloured interface elements was to make the screen look too brightly coloured - such trivia should not bother anyone in the quest for best Photoshop image quality, but as I said, I just don't do the sort of ultra precise sorts of work. A gamma of 2.2 looked better and had minimal effect on what I could see in images in Photoshop.

The software can take 5 to 10 minutes to do its stuff. For the NEC display, you are adjusting its internal lookup tables (LUTs) as well as creating a profile.

The device is supposed to be fully temperature compensated, allowing for reliable operation between 10C and 50C.

For both the NEC and my cheaper monitors, the software took quite some time iterating the greyscale values, stepping between different levels and adjusting settings.

The process works by displaying known values to the screen and then measuring just what is displayed.

If you are measuring a screen at a distance then the software can work in full screen mode, and there is and offset aiming chart for the built in targeting laser.

If you calibrate your screen from a short distance away then the calibration reflects the whole environment. You need a stable viewing environment and a non gloss screen to really benefit from this approach - this from the manual:

  • "You will encounter a major difference between contact measurement and close distance measurement in the shadow details. Monitor calibration with close distance measurement yields better shadow details because the incident light on the monitor will be accoun- ted for and will be compensated. The objective is to assess the entire workstation in step with actual practice (including monitor, ambient light and hood)."

The sensor has a +-4.5 degree viewing angle, although there is an optional lens (not tested) to reduce this to 1 degree.

Once the software has finished and you have saved a profile, then you can measure just how accurately everything is working.

This 'Validation' phase requires that you quit and restart the basICColor software - then recalibrate your measuring device when it's seen for the 'first' time.

  • Not sure why it's needed, but this just seems a pointless step - you don't do the profiling often, but it's one of those minor irritations you find in software :-)

Some results

The results of calibration/profiling are evaluated from just one point on the screen - there are no measures of screen evenness.

I've shown some of the output charts from different setups. I've also included a link later to a zip file of profiles that I created, just in case they are of interest to anyone - let me know if you find anything of interest in them!

First up, my Apple 23" Cinema display, using an i1 Pro

Below, the same display, but with the Discus

With the NEC monitor and the Datacolor Spyder3 colorimeter (note that this was an early version of the S3, so I'd expect current versions to be even better)

With the NEC monitor and the Discus (L*)

And lastly, the NEC and the Discus, but this time with an Gamma 2.2 tone curve.

I did loads more different settings, but there are only so many graphs like this I'm going to include...

Using this software, the Spyder3 generally surpassed the i1 Pro, particularly in the darker colours.

The Discus produced the best profiles for all screens I tested, and indeed, even though the sensor has gone back, I'm keeping the Discus profile for my Cinema display and 2nd display, since both are better in neutrality and shadow areas than I usually get - not by much, but I believe I can (just) see some of the differences when editing images. I only tend to calibrate my monitors every month or so, and will see what changes. I've been considering replacing my Apple display this year, and the results from using the NEC for a week are interesting. I'll write up more about this when I have the spare cash for a good new monitor, or the Apple one dies...

Using the Discus - projectors & ambient

Unfortunately the basICColor software will only work on one computer, so my plans to test projector profiling and profiling my MacBook Pro were thwarted.

However, I'm told that the basICColor software currently costs £85 for the first license and £42.86 for additional copies, so I can see that some organisations might want to extend its use to laptops and projectors. Given that some other projector profiling solutions are licensed for the device and not the computer, I do wonder how many would make wider use of the discus?

I did plug the projector into my main computer and test the software with an image projected onto a wall, but this is hardly a test likely to reveal much of interest.

The device includes a red laser to assist in alignment and measurement accuracy when performing remote readings (monitors or projected images)

  • ...I did mention that I'm perhaps not in middle of the target market for this software and hardware ;-)

Discus - built in red laser

The ambient light measurement options are similarly limited, so any viewing booth you might want to measure needs to be suitably close for a long USB cable...

After calibration of the device you need to move the ambient light measurement filter over the sensor

Move mouse over image to see

I'm assuming that the main use of the ambient light measurement function is for viewing lighting and the like, since projectors and projection screens vary a lot, and I'd suggest they rarely require the precision and repeatability that this device is capable of.

Conclusions

I don't often compare products, but with the basICColor software, this device produced the best looking profiles I've seen on my Apple Cinema display. It handled the wide gamut NEC Reference 271 display perfectly.

However, as I'll freely admit, my work does not require the levels of extreme accuracy and repeatability that is often found in some design, proofing and print environments. I don't need to check that the calibration and uniformity conform to elements of ISO 12646 or the requirements of printing standards organisations such as FOGRA

If you are getting grey desks and walls, custom lighting, and spending thousands on monitors, then this device is squarely aimed at you. If you work in an environment where putting a red coffee mug on your desk will affect your work, then at last a colorimeter to meet your needs is here.

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I don't have access to the expensive colour measurement devices needed to test just how accurate the Discus actually is (since one would cost several times what I just paid for a car ;-) so you'll need to do your own testing.

The device has taken some time to appear since its announcement at Photokina last year (2010) and at the moment is only supported for general use by one software package.

The basICColor software that I tried is easy to use, although the licensing method means that calibrating laptops and projectors is a less attractive option, particularly given the availability of other packages offering projector calibration without such restrictive licensing.

The Spectraview software supplied with the NEC display currently does not support the Discus, but we're told that a compatible version can be supplied via basICColor (FOC).

A superb bit of engineering, even if some of its finer points are perhaps a little wasted on me ;-)

If you've any questions or comments - please let us know, or leave a comment on our blog

Article History - first published April 2011

Summary

Precision USB connected colorimeter for monitor and projector profiling, with ambient lighting measurement and support for Normlicht adjustable lighting.

Software requirements

More Info

The views in this article represent those of Keith Cooper.
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