ColourKit FFEI Digital Camera Chart
The purpose of a digital camera chart is to characterise the camera in the lighting conditions being used. The chart is photographed in the lighting conditions used and a profile is made by comparing the camera RGB colours with the CIE colours of the chart as measured in manufacturing. It is then critical that the chart looks the same in the photograph as when it was measured. This means there should not be any gloss effects where light from the source is directly reflected back into the camera. To aid the photographer with this we do not have any gloss patches in the chart and the chart is made from very matte paper. Some charts have gloss patches and even silken patches where small amount of gloss effect are seen, almost imperceptible to the user but the software can easily detect it. Not only do we use matte paper to eliminate gloss effects but we print the chart with colour fast inks so, if treated with care the chart will last a long time. To increase the range of the chart so shadow areas are handled correctly we have attached flock patches which make the chart much darker than any matte print process can deliver.
The chart comes in two sections. One covers the whole area and is a randomised chart area which reduces the problems of the illumination being none uniform not only in light level but also in colour. If for instance you have all the green patches on one side of the chart and that side of the chart was illuminated in darker, yellowier light then after profiling all the green colours would come out lighter and bluer because the profiling software will compensate for all the different light on the green patches. Having random patches spreads out the effect of the varying illumination so each colour region will have some patches from all the illumination conditions on the chart. Thus the profiling software will balance out the corrections made and one colour will not be unduly effected by one lighting condition.
There is a second, small chart in the lower left hand corner. This is for use in shooting very small field of view shots; for instance products like perfume bottles. In this case you just put the small chart into the field of view without having to undo your photographic set up just to shoot the chart. Just place the small chart into the field of view and use the small chart data set.
Each chart comes with its own data set.
- Non Reflective, matt patches
- Special black reference patches
- 2 charts in one to suit the scene being shot
- Randomised patch arrangement to minimise effect of variations in lighting angles and colors