Dickson, Addison, Ill., offers a comprehensive calibration guide which covers all aspects of instrument calibration. Instruments lose accuracy over time due to normal usage and the environmental conditions to which they are exposed. Periodic National Institute of Standards and Technology certified calibrations maintain the accuracy of data loggers and chart recorders through their lives. Periodic calibrations that include both before and after calibration data are the only way to ensure that measuring instruments are accurate and can identify out-of-tolerance conditions. Dickson’s Calibration Guide explains further why calibrations are required, a review of methods to choose from, a step-by-step guide to developing calibration schedules and much more.