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Datacolor SpyderCheckr - Review
A colour test card and software for colour calibration and photo adjustment
Datacolor have produced a coloured test target and software that aids fine tuning of the colour response of cameras. It works with Adobe Lightroom, Photoshop, Elements or ACR (Adobe Camera Raw).
Keith has been giving the SpyderCheckr a test, looking at how you'd use it, and how to ensure that it gives you the most useful results.
Accuracy in digital imaging
Any (colour) camera is building up image data from a number of sensor pixels with different colour responses.
Even allowing for the multitude of sensor designs, the image data you get is the result of a series of processing stages, each based on measurements and assumptions ranging from photon absorption in silicon through to he vagaries of the human visual system.
The more you look at the details, it's a wonder that colour photography works at all...
All the different processing steps (whether in camera or on your computer) are directed at producing a final image that you can use for whatever you want.
One problem is that lighting is rarely constant and predictable in photography. This can result in cameras having difficulties in accurately recording some colours.
Setting the camera white balance addresses much of this, and for many photographers that's about it - well not even that, since many never adjust white balance and trust the camera to get it right.
Other photographers may delve into the camera settings and find picture styles and settings that alter the look or 'style' of the image.
I'll come back to the distinctions between 'pleasing' and 'accurate' later, but there are occasions where getting one or more colours accurately represented is very important.
If I'm doing any work that includes a corporate logo, I'll usually check to see if there are any special requirements for its representation.
The camera manufacturers go to great lengths to ensure that their products can produce 'accurate' results, but they can't know every light source and subject, so invariably the results are a compromise.
This may or may not matter - when it does, the SpyderCheckr is aimed at helping improve the quality (as in fitness for purpose) of your images.
The SpyderCheckr is a rigid case that holds the two double sided colour targets safely inside.
Note the tripod fitting at the base - this allows the target to be placed on a tripod or light stand.
The full grey target (10% steps)
The colour target has a useful patch that will change colour with cumulative exposure to light.
When it goes yellow, it's time to replace the cards (spare cards will be available in 2011). It is designed to fade from red to yellow after the equivalent of 30 days of full sun in the US Southwestern desert.
Whenever I've used similar cards in the past, you are always encouraged to change them regularly, but with no idea as to how often - I keep all such items in a drawer, out of the light, so they -should- last for years.
If I regularly used one on outdoor shoots, then how long should they last?
There is a version of the SpyderCheckr available which includes a SpyderCube. (SpyderCheckr pro)
Here it is, mounted on the top of the SpyderCheckr, via the extending tripod screw thread.
I've written up a review of the SpyderCube, that covers its use in some detail.
The whole idea behind the operation of the SpyderCheckr is that you take a photo of the card, then process the image to create an image file that the SpyderCheckr software can analyse to create a set of corrections that you can use when processing your images.
The processing is even easier if you use Lightroom, where various exporting options are supported.
However I don't use LR, so what you see here is the Photoshop/ACR workflow - mind you, the whole process takes about as long to do as it's probably taken you to read the last few paragraphs...
Here's a photo I've taken of the test target - illuminated by diffuse daylight.
I'll come back to lighting related issues, but you do have to be careful to light the SpyderCheckr evenly and away from any reflected sources of light.
Once I've processed the RAW file from my Canon 1Ds3, I can save it as a TIFF file for analysis.
I've set the white balance during conversion, by using the light grey patch E2.
The software has one basic function - it processes an image of the target.
You do need to crop the file to encompass just the target.
Once opened, I check that the small squares all fall on target squares.
After aligning things, I have the option to save a calibration to ACR or Lightroom.
There are three different calibration options (descriptions from Datacolor)
The differences are quite subtle and may not show on some images.
It's worth noting that most modern cameras will be getting quite close to what you are looking for, so don't expect vast changes unless you are using quite poor types of lighting.
It takes only a few seconds for the calibration to be created - do remember to give it a meaningful name.
The one below, for example, was after creating a calibration for some CFL flat panels I sometimes use for product photography lighting.
After the calibration is saved as a 'Preset', you can use it on any image (it sets HSL slider values).
The detailed settings of the various individual HSL adjustment sliders are still available to alter even more if you want to fiddle with things even more...
I did think of including a lot more examples, but you're looking at subtle colour differences in sRGB files via a web browser - as such I've no idea what this image looks like on your monitor...
At least the 'Coke red' looks OK on my monitor.
Some areas to take care
The example above was lit with diffuse daylight so I could just expose as I would normally.
However in warmer lighting, tungsten for example, the amount of red light is much higher than blue. This results in clipping of the red channel if you're not careful.
The bright yellow patch is particularly prone to this, so you might want to bracket exposures.
The histogram shows measured values for the white patch (E1) of 244,243,244.
However, notice the red spike at the far right, and the red clipping indicator above it (this from ACR, when looking at RAW files)
This shows that the red channel is clipping in the image.
It's no good trying to make calibrations where a channel is clipping, you need to use 'clean' data.
The example below shows a number of shots of the SpyderCheckr lit by some energy saving light bulbs
The selected RAW file is the first one with no clipping in the red.
The quality of your calibrations (or any colour management related work for that matter) does depend on getting good data to work with.
There is a comprehensive user guide available (on-line PDF) which is well worth reading before you start.
Just because the software is so easy to use, don't skimp on photographing the target.
The screenshot below, shows the target image cropped from the photos above.
I've cropped and fixed perspective in ACR - it doesn't matter if you need to warp the image to fit, what's important is getting those small squares to fit inside the target patches.
This is the source image, converted to sRGB for web, although you should use a larger space such as Adobe98 for actual calibration creation.
The dark blue is perhaps the most obvious hue shift.
Two existing calibration files can be combined using the software, to make a third new calibration that reflects a mix of the other two. This allows light source balancing, although you might just decide to shoot a new picture of the SpyderCheckr.
The SpyderCheckr is solidly built and will protect the targets from damage.
Careful lighting setup is very important if you want the best results.
The shot below shows some slight marking of the target and specular reflections from the frame. This is not good lighting.
I should note that I was looking at an early review sample of the SpyderCheckr, so the marks are not typical - I'd suggest trying to avoid touching or marking the target sheets.
The target layout to the right side matches other industry standard layouts, whilst the colours on the left hand side provide additional skin tones, greys and low saturation colours.
The table of colours and their reference values below are from Datacolor's web site
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The calibrations can be applied to any existing RAW conversion setup, so could be used to fine tune DNG profiles if you were using them - you can use both techniques together, but do remember to note down settings, since the more different adjustments and fixes you use, the easier it becomes to forget something.
How well did it work?
It's simple to set up and use, and with awkward lighting it can make a real and noticeable difference. You do need to take time to light the card evenly before photographing it.
However I'm reminded that accurate colour is not always the most pleasing colour.
Accurate colour matters more when I'm photographing products and company logos. Pleasing colour trumps accuracy for much of my other work.
I now have at least four different ways of calibrating/profiling cameras here at Northlight, not to mention all the different ways of processing my RAW files.
Depending on your needs, one method may be more appropriate than others for your workflow, however results from my testing shows a positive improvement from using the SpyderCheckr.
For most work though, my camera works just fine and I don't use any specific correction profiles (of any sort)
However, I know that when I'm taking shots where there is low quality lighting, such as a mix of energy saving light bulbs and fluorescent tubes, I can quickly create a preset that will likely improve the colour rendition of my images.
A solidly constructed 48 patch colour reference target. Software enables colour correction calibration sets to be created for use in Lightroom or Photoshop (Elements too).
Available in versions with additional SpyderCube device.
The SpyderCheckr includes:
The SpyderCheckr Pro includes:
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