basICColor caliCube and GreyCard
digital camera Grey-balancing tools
Color–solutions have produced a special Greycard and, for even more assistance, the basICCaliCube, both are useful aids for a digital photographer, utilising a superior type of material for the Grey-balancing of digital cameras. More on the cube below on this page.
The practical science:-
Digital photography offers the user a wide range of new possibilities. Color fidelity in particular can be improved tremendously. Instead of two conversions (Original – [Photography ] – Film, Film – [Scan] – File) only one is required (Original – [Photography] – File). Color conversion from original to film is obsolete. That is the step which is not easily controlled, while scanning delivers very exact color reproduction when colourmanagement is applied. Merging of the capture and the scanning process in digital photography eliminates color problems in film that otherwise cannot be corrected. In order to achieve exact color reproduction, the digital camera needs, ideally, 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. While all ICC – compatible programs (camera software, Photoshop, InDesign, RIPs, . . .) are based on the internationally standardized (through ISO standards) lighting D50 (daylight, 5000 Kelvin, equals approximately sunlight at noon), photographers are dependent on the actual lighting in the current scene.
When working with different illuminants, metameric failure will occur regularly. The color of two objects will look the same under one light, but they differ under another light. In everyday life you see this effect when shopping for clothing – clothes match under shop light and do not match under sunlight – or vice versa.
A white balance target bears a special relevance in respect to metamerism. If the photographer uses a metameric Grey card for this purpose, (and, many commercially available Greycards are metameric) all images taken under a non – D50 lighting situation will produce a color cast, although the camera had been calibrated to Grey. The cast depends upon the type of metameric failure. This effect is known for most Grey cards, even from well known manufacturers in the photographic industry. That’s why Color Solutions developed the basICColor Grey card . Because of its spectral remission properties, it is virtually free of metameric failure. The color shift under different lighting situation remains way under the threshold of visual perception. Or, in brief, the basICColor Grey card looks the same under all viewing conditions: Grey without a cast. Most Greycards do not have this property.
option/alt click here to read more download an info PDF for basICColor Greycard
basICCaliCube
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 midtones will be hard to evaluate when establishing highlight and shadow points.
Placing the Cube 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 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 card. 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 temp. If you use a spectrally neutral Grey card 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 2006
Using the basICCaliCube
by industry guru Thomas Holm of Pixl:
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, more detail - 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, , 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/Greypoint 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 GreyCard), the rest is a question of hue/sat and possibly selective colour adjustments to make skin tones and memory colours appear more pleasing.
option/alt click here to to download an info PDF for basICCaliCube
More from basICCColor:
There are many interesting and useful products from color-solutions in the range, please click here to go to the basICColor website for more info. Once at the home page, Alt Click on "product overview" at top right, to download a pdf with a summary of the full basICColor software range.
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