An electrographic image forming device may use a feedback loop to determine environmental conditions and accordingly set one or more operating parameters. The device may detect a resistance/capacitance characteristic of a feedback loop comprising an interface between a first component and a second component of an image forming unit. The device may detect temperature measurements and humidity measurements that can be used to calculate wet-bulb temperature or other metrics used to characterize ambient environmental conditions. The interface may be one in which a toner image is transferred during image forming device operation. A controller may adjust the resistance/capacitance characteristic in response to wet-bulb temperature in conjunction with measured transfer feedback voltage.