A Picture of a Spectrum with a Measuring Scale
•Item No. 1: Light for back lighting
spectrum measuring scale.
•Item No. 2: Rheostat for adjusting light
intensity.
•Item No. 3: Spectrum measuring scale.
•Item No. 4: Window to allow light to strike
scale.
The scale box apparatus is juxtaposed beside the spectrum emission source. The camera should be focused on the center of the scale. The scale size is relative to the distance of the camera from the scale, and the zoom setting of the camera. As distance and/or camera zoom is changed the spectrum relationship to the scale is also changed. To maintain consistency, it is imperative to us a camera tripod and a zoom setting that can be consistently reset.
The camera should be on a level plane with the emission source. The spectrum may or may not fall where desired with the measuring scale. Proximity of the scale box to the emission source, and camera distance can be adjusted as necessary. The window, item #4, is sized so that the scale can be adjusted up or down as necessary for proper spectrum placement. Alternately, the scale box can be set on a height adjustable stool or similar device to allow proper elevation.
The scale, item #3, is printed on typical
typing paper. The scale is then mounted on a piece of craft board
with an exact scale sized window cut out of the craft board. The
craft board is then pinned to the scale box with "T pins.
Note that the scale can be customized as desired and printed out on
regular typing paper.
The rheostat controlled light is placed in the scale box to back light the scale. The rheostat serves two purposes. 1) The rheostat allows the intensity to be set for the best rendition of the scale in the picture. 2) The primary camera used in this project automatically adjusted the exposure for the light conditions. Typically the spectrum was overexposed. By increasing the intensity of the scale lighting, the proper exposure setting can be captured prior to snapping the picture. Also, the typical subdued lighting conditions made it difficult for the auto focus feature of the camera to lock in a focus. Focusing on the well lit scale made it easy to lock in an appropriate focus and exposure setting. Once these two setting are locked in, the scale lighting can be reduced with the rheostat for proper texture prior to taking the picture.
