The HD Studio Kit 4 includes four charts and a fold up super black hole which is easy to handle and increases the contrast between the white patch and the two dark holes to at least 2000:1.
The charts for the folders are produced of special photographic material of high light stability, mounted on a 2 mm plastic plate.
The ring book folder protects and stores the charts, no more searching lost charts. At the same time the folder serves as a robust upright support for the charts: flip over both parts of the cover to the back and fasten with velcro tape, that’s all. Charts that are not in use are simply flipped forward. When the folder is hung on the wall, two test charts - one above the other - can be presented at the same time. A sprung metal clamp holds the charts in upright position.