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calicube and coloured pensbasICCaliCube and basICColor Gray card - Review

Specialist grey card and cube for getting your photos right

The CaliCube and Grey Card from German company basICColor, are simple tools that can help improve the quality and consistency of your white balance and exposure choices.

Using the Grey card/cube

Keith has been trying out both as part of his day to day work, to see if they make a worthwhile difference, or just get left in the gadget bag.

Note - April 2009
A new version of the cube - the SpyderCube is announced by Datacolor. We have a full review

Grey Balance (aka white balance)

Your eyes adapt very quickly to changes in the colour of lighting, however cameras aim to just record what's there.

Without the lighting environment that your eyes adapted to, it's quite likely that a picture taken in particular lighting conditions won't look right on your screen or print.

Fortunately this is such a fundamental problem that camera manufacturers have gone to great lengths to try and duplicate this aspect of our visual system. It's called white balance, and is your camera software's technique for compensating.

I'm not going into a lengthy discussion of how your camera (or raw image processing software) handles this, but usually you can assume it makes a good job of it.

Unfortunately not always, and sometimes you might require even more accurate rendition of a scene than the camera manages.

Much more useful is a piece of grey card that you can include in a photo and then use it afterwards to set the colour balance.

Many people use an old 18% grey card from their film photography days, however not all cards are created equally...

The Card

The basICColor card is a ~25cm x 19cm (~ 7"x 10") 3mm thick sheet of plain grey plastic. It has a semi-matte finish to give good even reflections of incident light, although the slight sheen can catch the light at some angles.

It's worth noting that whilst cameras record colours in a similar way to our eyes, they don't work quite the same.

As such, different coloured object that look the same to us, can look different in different lighting (and with different cameras). This effect is easy to see if you get two different items of coloured clothing that look similar in domestic lighting, but no longer match when viewed in daylight.

grey card used for light checkThe picture to the right shows the card being used to check the light for taking some jewellery photos. There is both incandescent lighting and daylight.

This shows as slightly different colours across the card. I was using my old Canon 1Ds for these shots since the 1Ds3 was off for a service.

The older camera needs more care when dealing with such lighting.

You can see a different white in the far computer screen as well. At a colour temperature of ~6500K it looks quite blue in comparison to the room lighting at ~2900K.

There are loads of parts of the image I could set the white balance from, when processing the raw file, but it's nice to have a consistent option in the grey card.

Ordinary photographic grey cards are designed to reflect 18% of light that lands on them. This enabled them to be used with a meter to get accurate exposure for film...

  • Well, 18% is the figure you'll see quoted all over the place. The actual ANSI standard that camera manufacturers use for calibration is around 12%. If you are going to use a grey card for exposure, then you ideally need to do some test shots under controlled lighting. I've linked a very good article, by Thom Hogan that explains this all very well, in the references at the end of this page.

For the digital cameras we're using, the '18%' card is a bit too dark for good grey balance. The basICColor card reflects 25%. There are more technical details for the grey card in the references at the bottom of the page.

If you're using higher ISO settings on your camera, then the dark colour will exacerbate any noise and could lead to errors in setting the correct white balance. If you are using an eyedropper tool to sample a noisy image, then don't forget to make the sample an average (of say 3x3 or 5x5 pixels, such as you can select in Photoshop).

Traditional cards were designed for exposure rather than white balance, so were not always spectrally neutral. They might look grey, but if you measured the light reflected, then just how colourless they are varies with different lighting types.

The grey of this card is almost 'extra gray' - it should add no colour of its own to reflected light (more detailed specs below).

calicube and coloured pens

The Cube

cube featuresThe card is great for setting white balance where the automatic systems of the camera need a bit of help.

With some experimentation you can even use it to refine exposure.

What about using something like the grey card to check for lighting levels in a studio environment, such as where I might be doing some product photography?

This is where the basICCaliCube comes in.

As well as the same 25% grey face of the cube, there is a white face and a black face. If you look at any corner you can see all three face types.

These three faces of the cube allow you to make sure you've got a good range of exposure.

What about brighter than white and darker than black?

There is a chromed ball at the top of the cube to pick up specular reflections (or 'catchlight'), such as your lighting sources.

The cube is also hollow with light absorbing material inside. This gives a true black i.e. no light.

What importance are these extra bright and extra dark areas?

If I'm photographing jewellery for example, the quality of the specular reflections makes a big difference to the sparkle that you see. The more detail you keep in highlights, the darker the rest of the piece looks.

Similarly, the absolute black allows me to set a black level in my raw processing that avoids sensor noise without losing shadow detail.

In the next section I've some examples that should show the general principles of what I'm doing.

grey cube features

Note how, with bottom lighting, the black face of the cube is quite bright (it reflects no more than a few percent of the light). The absolute black of the hole shows up well

In use

First up, one of my pet hates - 'Energy Saving Light Bulbs'

The nasty uneven spectrum of one of these (in a hallway in my house) has confused even the 1Ds3

Roll your mouse over the image to see an example of correcting with the grey card. Just as in the example above, you can see how the card has picked up slight variations in the quality of the light.

using card to get correct white balance

If you look very carefully you can see that for the corrected version I'm using the large ProPhoto colour space.

The glass of pens contains some very intense colours, some out of the range that can be covered in the sRGB colour space.

I've a detail of the histogram below (from ACR 4.5) If you move your mouse over the image you can see the reduction in clipping when selecting ProPhoto.

Whilst it may not make a lot of difference when shooting many natural subjects, a bigger colour space (if used with care) can be useful for capturing better shots in awkward lighting and with strong artificial colours.

The shot below is a corrected version of the shot (in sRGB) - not at all bad given the lighting!

The next shot shows the pens lit with a mixture of halogen lighting and diffuse daylight (from the right).

You can see the windows in the reflection on the chrome ball.

The screen shot below shows a range of exposures in 4 raw files opened up in ACR4.5

The most useful exposure was the one below where the highlights are just showing clipping.

The RGB values below the histogram are from in the 'true black' and show up as a small spike at the left hand side of the histogram. I'd probably move the 'Blacks' slider up a bit to make this black nearer to zero.

Two different exposures (move your mouse over the image) show that there is still a bit of light coming out of the hole, although visually it looks completely black.

The light trap is very effective. It actually looks 'extra black' when you look at it too - most odd in daylight. What we perceive as black, often isn't.

The two different versions of the shot below (move your mouse over the image) show the difference in handling specular highlights. This makes quite a difference in photographing any shiny objects.

The cube covers all the exposure and white balance aspects of lighting that I'm likely to want to adjust for when I'm setting up a product shoot (I often work on location).

Buying a cube

We make a specific point of not selling hardware, but if you found the review of help please consider buying a cube, or any other items at all, via our link with Amazon.
Amazon UK link / Amazon Fr / Amazon De
Amazon USA link / Amazon Canada link

It won't cost any more (nor less we're afraid) but will contribute towards the running costs of our site


Amazon.de Spydercube

Conclusions

Useful if you were setting up some permanent lighting, where you could experiment and work out optimum exposures and white balance for various configurations. I can see the card also being of use when setting up adjustable viewing lighting for print evaluation.

My work conditions are much more variable (I sometimes work in factories for example) with differing light levels and lighting types.

Something like the grey card, or cube, just helps bring an extra bit of consistency to my work.

It can also help you think about lighting and white balance in a more detached way, without having to think about the actual object you are photographing.

The chrome ball on the cube is particularly useful for detecting unwanted light sources and reflections that you might not want in your shot.

One thing I would suggest though, is that you get something to keep the items in. Neither are supplied with any protective storage, so I keep my grey card in a plastic wallet and the cube in an old soft lens pouch.

Simple, easy to use and no batteries to ever replace ;-)

Summary

Grey card and calibration cube from basICColor in Germany (see site for list of international dealers).

The card currently costs 30 Euros and the Cube 69 Euros.

See also our Spydercube review

The following data is from the manufacturers and covers the neutrality of the Card (see PDF below for more details).

Lighting basICColor gray card Other gray card
a* b* a* b*
Standard illuminant A -0.26 -0.46 -0.46 +2.24
Standard illuminant C -0.10 -0.42 -1.52 +2.59
Standard illuminant D50 -0.18 -0.41 -1.11 +2.48
Standard illuminant D65 -0.13 -0.39 -1.51 +2.63
Standard illuminant F2 -0.06 -0.48 -1.17 +2.66
Standard illuminant F7 -0.07 -0.44 -1.58 +2.63
Standard illuminant F11 -0.12 -0.53 -1.52 +2.70
Standard illuminant F12 -0.17 -0.53 -1.24 +2.83
Standard illuminant D75 -0.11 -0.38 -1.71 +2.69
Metameric Failure 0.20 0.14 1.25 0.59

Standard illuminant A has a colour temperature of 2856 Kelvin, D75 has 7500 Kelvin F2, F7, F11, F12 are fluorescent lamps.

More Info

The views in this article represent those of Keith Cooper.
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