A document reading device for optically detecting an authentication document, the document reading device comprising: a translucent support for applying the authentication document, wherein the translucent support is transilluminatable with illumination light for an image capturing of the authentication document; an image detector for the image capturing of the authentication document, wherein the image detector is arranged in the translucent support, and a communication interface, wherein the document reading device comprises an illumination device with at least one light source, wherein the at least one light source is configured to illuminate the authentication document with the illumination light for image capturing, wherein the document reading device comprises a processor, wherein the processor is configured to detect a feature of the authentication document in the image capturing, wherein the illumination device is an external illumination device, wherein the external illumination device comprises a communication interface for receiving control signals for controlling the at least one light source, wherein the control signals specify a wavelength range and/or a light brightness and/or an illumination duration of the light source, wherein the communication interface is configured to send out the control signals to the at least one light source, wherein the communication interface of the illumination device is configured to send out an illumination light signal to the communication interface of the document reading device, wherein the Illumination light signal indicates the wavelength range of the illumination light, wherein the communication interface of the document reading device is configured to receive the illumination light signal, wherein the illumination light signal indicates the wavelength range of the illumination light, and wherein the communication interface is configured to control the processor for detecting the feature by the illumination light signal. a translucent support for applying the authentication document, wherein the translucent support is transilluminatable with illumination light for an image capturing of the authentication document; an image detector for the image capturing of the authentication document, wherein the image detector is arranged in the translucent support, and a communication interface, wherein the document reading device comprises an illumination device with at least one light source, wherein the at least one light source is configured to illuminate the authentication document with the illumination light for image capturing, wherein the document reading device comprises a processor, wherein the processor is configured to detect a feature of the authentication document in the image capturing, wherein the illumination device is an external illumination device, wherein the external illumination device comprises a communication interface for receiving control signals for controlling the at least one light source, wherein the control signals specify a wavelength range and/or a light brightness and/or an illumination duration of the light source, wherein the communication interface is configured to send out the control signals to the at least one light source, wherein the communication interface of the illumination device is configured to send out an illumination light signal to the communication interface of the document reading device, wherein the Illumination light signal indicates the wavelength range of the illumination light, wherein the communication interface of the document reading device is configured to receive the illumination light signal, wherein the illumination light signal indicates the wavelength range of the illumination light, and wherein the communication interface is configured to control the processor for detecting the feature by the illumination light signal.