Last Updated: 13/04/2016
sophisticated dynamic range and grey balance calibration helper
basICColor have produced a rather special grey balancing tool utilising a superior type of material, which also assists with tonal range setting; properly accurate grey balance is a vital aid for the digital photographer. see also the basICColor Grey card
dynamic range and calibrated grey balance helper
As well as neutral grey balance, achieving critical digital photo accuracy requires control of the following parameters: well placed highlight values, deep/rich Dmax (shadow) values. The basICCaliCube offers multiple functions in one calibration device. It shows you
1: absolute-black, in the black trap
2: black with just noticeable detail, black face, reveals sensor noise
3: clean highlight values showing just noticeable detail, white face
4: specular highlight, no detail (255,255,255), chrome ball
5: neutral midtone grey, grey face.
With only a few eyedropper clicks, you can optimise the image within Photoshop / Aperture / Lightroom / or a RAW converter.
it's worth understanding the practical science
Digital photography offers the user a wide range of new possibilities. Colour fidelity in particular can be improved tremendously. Instead of two conversions (Original object via Photography to Film, then, Film via Scan to File) only one is required (Original object via Photography to File). The colour conversion from original to film is obsolete. In a film based workflow, the original to film step is not easily controlled, whilst the scanning process delivers very exact colour reproduction when colour management is applied. In digital photography, the capture and the scanning process are effectively merged and this eliminates colour problems intrinsic to using film that sometimes cannot be corrected.
So, digital capture has a big advantage, but in order to achieve exact colour reproduction, the digital camera needs to be calibrated and profiled – just like the scanner – in a conventional two step process.
Variations in lighting conditions present a special challenge in digital photography. Whilst all ICC – compatible programs (camera software, Photoshop, InDesign, RIPs, etc. . .) are based on the ISO standard lighting of D50, digital photography is dependent on the actual lighting in the current scene.
When working with different illuminants, metameric failure will occur regularly. This metameric failure shows itself as follows: the colour of two objects might look the same under one light, but they may cease to match under a different light. In everyday life you see this effect when shopping for clothing – clothes which match under shop light may not match under sunlight. Shoes and handbag? Grey jacket and trousers? We've all seen this.
Of course if objects don't match each other under your shooting light, then no white balance or grey balance is going to fix that. But, using a high quality non-metameric grey device like the Cube simply means that the grey device itself always "looks" grey and, thus, balances the capture correctly which is an excellent first step.
A white balance target bears a special relevance in respect to metamerism. If the photographer uses a metameric Grey object for this purpose (and many commercially available Grey cards and similar greybalancing tools are metameric) all images where such an object is used under a non – D50 lighting situation will produce a colour cast, even though the camera had been calibrated to Grey. The resulting colour cast depends upon the type of metameric failure. This effect is known for most Grey cards and greybalancing tools, even those from well known manufacturers in the photographic and colour management arena. That’s why basICColor developed their special Grey card and the basICCaliCube. Because of their spectral remission properties, they are virtually free of metameric failure. The colour shift under different lighting situations remains way below the threshold of visual perception. In brief, the basICColor Grey card and basICCaliCube look the same under all viewing conditions: Grey without a cast. Most Grey balance tools do not have this property.
Competitive solutions fail to provide an 'absolute-black' for eyedropper "end point" selection. Because of the Cube's integrated light trap, pure black can be defined. The black face of the Cube also supports setting a just noticeable difference black point (with detail) definition.
The chrome ball provides specular highlight definition. Because of its 100% reflection, pure highlights can be selected. The white face of the Cube also supports the setting of a just noticeable difference highlight (with detail) definition.
metamerism free grey-balance
Neutral grey under any lighting condition. The completely neutral grey face on the Cube is based on the optimal 25% quarter-tone value. This equates to the standard print value of L*= 60.
- Neutral, metamerism-free grey, for a perfect camera colour temperature balance
- Chrome ball for specular highlight definition
- White and black patches for designation of contrasting highlight and shadow with detail
- Light trap for designation of the absolute-black end point
- Optimal tool for an ideal camera RAW workflow
- Accelerates production through known target reference points, using simple and easy eyedropper clicks
- Perfect for both controlled and natural lighting
an expert photographer's view of the basICCaliCube:–
After only a couple of months of use, I can say that this little tool has simplified the whole process of evaluating shadow and highlight areas in an image, especially when shooting raw and especially when photographing scenes that have no proper highlight area or full tonal range. For example, a landscape which consists mainly of mid-tones will be hard to evaluate when establishing highlight and shadow points.
Placing the basICCaliCube in a shot gives all the information needed to properly set white and black points for a given lighting set–up, whether artificial or natural. The Grey face of the Cube is for setting a mid–tone and is particularly useful as it is spectrally neutral... which means it won't change colour under different lighting conditions unlike some popular grey balance tools / grey cards. Imagine shooting a bunch of garments somewhere outside... the weather is variable; some cloud cover, some sun... you do a reference shot each time the light changes with a (non–spectrally neutral) grey balance tool. When you come to process the raw files, you use each reference shot to neutralise on and find that... oh dear... each batch of images has a slightly different colour. If you use a spectrally neutral Grey card or basICCaliCube instead, though... consistency reigns. Which means time saved.... and time is...
The only thing you need in addition is something to hang the Cube off!
Nick Dunmur, Photographer
using the basICCaliCube
industry guru Thomas Holm of Pixl: "how I use the Cube"
Basically, first set the white point, then the black point. This will fix the tonal range and make highlights and shadows neutral. Then, try with the Grey eyedropper. If the Grey doesn't work either delete the points in the individual RGB curves or try to adjust them to make things look right. Then do either hue/sat or selective colour adjustments. Next you might play with making selections if you still have areas that do not appear as you want them. This procedure goes for most any type of image colour correction.
the process Thomas uses - in Photoshop's curves dialogue
Set a white point using the eyedropper (but do set the eyedropper level first, i.e. [double click it and adjust each target]. For setting white with some detail [as on the white face of the Cube] this value would be about 247/247/247, experiment with your images, and, after clicking, look at the level of the spectral highlight on the chrome ball, this should be near to 255/255/255, generally).
Set a black point (again set the eyedropper's level first [double click it] for black with some detail as on the black face of the Cube, this value may be about 10/10/10, again experiment and observe the level of the area in the black hole - for absolute-black [the black trap], this should be near to 0/0/0, generally).
Once Black and White are set, you can now set a Grey point, so you will have a neutral Grey balance.
You can only place the Grey point after the Black and/or White points. If, after setting Grey, you click with either the white or black eye dropper any other adjustment to the (R+G+B) curves is erased, so you'd have to redo the Grey point. Check the individual channels after setting white + black, then Grey, or black + white, then Grey.
Having set the initial Black/White/Grey-point in curves, now save the curve. Apply this curve as a starting point for the real images from a similar shooting scenario.
Of course, ease of success depends on your light source. The fuller spectrum, the easier this is (daylight is full spectrum). The more whacked the light is [maybe fluorescent?] the more adjustments you will need to do to obtain a pleasing image.
If you set the Grey eyedropper and the image as a whole "appears" wrong my answer would be to then slightly adjust the individual points of the curve in the R+G+B channels, this method achieves a shifted Grey-balance, e.g. perhaps for a sunset scene where the warmth of the light should be retained).
When the Grey balance is nailed down using a spectrally neutral object like the Cube (or basICColor Grey card), the rest is a question of hue/sat and possibly selective colour adjustments to make skin tones and memory colours appear more pleasing.