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. <EOS>