Test chart TE291 is a transparent test chart developed to measure the homogeneity of the LE7 uniform light box. Currently this chart is used by our production team during their final evaluations on the device to ensure that it meets our acceptance standards before shipment. The TE291 is primarily used to check for acceptable uniformity. If the uniformity is below the acceptance threshold, then the device must be recalibrated. We are now offering the chart to interested customers so they can check the uniformity for themselves throughout the service life of the device. The chart itself includes 63 transparent rectangles on photographic film and embedded between two glass plates. *Exact layout and dimensions may differ from image shown on the right.Test chart TE291 is a transparent test chart developed to measure the homogeneity of the LE7 uniform light box. Currently this chart is used by our production team during their final evaluations on the device to ensure that it meets our acceptance standards before shipment. The TE291 is primarily used to check for acceptable uniformity. If the uniformity is below the acceptance threshold, then the device must be recalibrated. We are now offering the chart to interested customers so they can check the uniformity for themselves throughout the service life of the device. The chart itself includes 63 transparent rectangles on photographic film and embedded between two glass plates. *Exact layout and dimensions may differ from image shown on the right.