Afdrukschaal

Afdrukschaal is a scale bar used in photography and printed reproduction to convey the actual size of objects in an image. It is typically a rigid, flat strip with alternating light and dark segments whose lengths are known, most often in centimeter or millimeter increments. Many afdrukschaal types also incorporate a color calibration panel or grayscale area to aid in exposure and color balancing. Some scales include both metric and imperial units.

The primary purpose of an afdrukschaal is to provide a measurable reference for size, enabling accurate interpretation and measurement of photographed subjects during analysis or publication. The scale is placed in the same focal plane as the subject and photographed with the same perspective to minimize parallax distortion. In scientific contexts—such as archaeology, forensics, biology, paleontology, and art restoration—the afdrukschaal ensures that images carry a traceable size reference.

Design features vary, but common materials include acrylic, plastic, or stainless steel, with typical lengths ranging from about 5 to 25 centimeters. Most scales show metric units, while some include imperial markings. Some versions are dual-purpose, offering both size markings and a color calibration target.

Usage guidelines emphasize keeping the scale parallel to the camera sensor, placing it near the object without obscuring important details, and ensuring it is visible in the final image. It is also advisable to note the scale’s position in image metadata and to avoid reflections or glare that could obscure markings.

Etymology: the Dutch term afdrukschaal combines afdruk (print or reproduction) with schaal (scale), reflecting its role as a reference scale in images. See also scale bar and photographic scale.