Technical Photography and MSI calibration card
CHSOS has designed the first calibration card for Technical Photography and Multispectral Imaging. Just one card for all the methods
Features for Technical Photography
Our card provides a simple and valid way to include reference standards for Technical Photography and Multispectral Imaging as well as white balancing and standardization of exposure and lighting control. This card is designed to be small so it can fit into the art documentation scene and it is robust and lightweight with a magnetic back.
Our calibration card is a unique tool that complements the Technical Photography and the Multispectral imaging kits. The four standard swatches on the top left are used to check Ultraviolet fluorescence photography (UVF). We decided to use 4 art materials to calibrate UVF images, they are shellac, madder lake, zinc white and cadmium red. The first 3 materials are characterized by their own typical fluorescence under UV radiation, respectively, bright orange, orange-red and yellow. On the other hand, cadmium red swatch has no fluorescence and we use it to check there is no light pollution casting on the UVF images. We also employ the cadmium red swatch to check and exposure correct infrared fluorescence photography (IRF). On the far top right there a gnomon for raking light photography (RAK) to document light direction angle. On the bottom left there is a 20 mm scale while on the bottom right we find the 6 multispectral imaging calibration swatches. We use the second gray of these swatches to exposure correct the visible (VIS), reflected ultraviolet (UVR), ultraviolet fluorescence (UVF), infrared (IR) and infrared reflectography (IRR). Eventually, we perform the white balance of the visible photo with the same gray. The gnomon on the top left has a rounded metal reflective top which we utilize to check polarized light photography images (the top of the gnomon appears dark if the polarized light equipment is set up correctly).
Features for Multispectral Imaging (MSI)
The reflectance calibration of the spectral images is performed using the TP–MSI calibration card as in-scene reflectance standards. Its white, black and 4 gray patches are used to calibrate the images Their respective reflectance values are (%): 100, 80, 60, 40, 20, 5.