The term "ground glass" refers to the texture of the surface, which has been physically ground or chemically etched into glass to scatter light. This texture helps to create a visible image for focusing and composition in traditional large-format photography.
The ObscuraFlex™ focusing screen is a proprietary combination of modern plastics with specific coatings and treatments that far exceeds the evenness and clarity of traditional ground glass. Years of development, testing, and experimentation have gone into creating the ObscuraFlex™ focusing screen and that experimentation continues today as new materials are tested and discovered. Considered the holy grail of camera obscura style digital photography, what makes the perfect focusing screen material is a hotly debated topic.
See below for example images...
