Method for verifying a value document or security document, comprising the steps: operating a display device, the display area of which displays a graphic representation, arranging, in front of the display area with the graphic representation, a security document, wherein the security document comprises a security feature including a visual barrier, that uncovers, when looked at in transmitted light at different viewing geometries, different pieces of information present behind the visual barrier, wherein the visual barrier is integrated into the security document such that, for at least one viewing geometry, a view through the visual barrier and through the security document onto a portion of information present behind the security document is possible, wherein the graphic representation comprises at least one first partial image portion for the at least one viewing geometry, and wherein, on the display area, in addition to the at least one first partial image portion, at least one second partial image portion is displayed, wherein the first image portion is represented configured as homogeneous monochrome, which incurs a first colour impression, and the at least one second partial image portion is represented, which is configured as homogeneous monochrome and incurs a second colour impression which is different from the first colour impression, detecting at least two images of the security document in front of the display device for at least two different viewing geometries, in that at least one first image is detected for a first viewing geometry and a second image is detected for a second viewing geometry which differs from the first viewing geometry, evaluating the at least two images detected, wherein, during the evaluation of the at least two images, a check is made as to whether the images comprise the first and the second partial image portions (101, 102) in such a way that the first image and the second image can be supplemented to form one total image, and from the total image, with a human observer, on the basis of a colour mixture, a monochrome colour impression is incurred, which is different from the first and second colour impression, and deducing therefrom a verification decision, wherein the verification result is dependent on whether the total image incurs, or not, a monochrome colour impression which differs from the first and the second colour impression. operating a display device, the display area of which displays a graphic representation, arranging, in front of the display area with the graphic representation, a security document, wherein the security document comprises a security feature including a visual barrier, that uncovers, when looked at in transmitted light at different viewing geometries, different pieces of information present behind the visual barrier, wherein the visual barrier is integrated into the security document such that, for at least one viewing geometry, a view through the visual barrier and through the security document onto a portion of information present behind the security document is possible, wherein the graphic representation comprises at least one first partial image portion for the at least one viewing geometry, and wherein, on the display area, in addition to the at least one first partial image portion, at least one second partial image portion is displayed, wherein the first image portion is represented configured as homogeneous monochrome, which incurs a first colour impression, and the at least one second partial image portion is represented, which is configured as homogeneous monochrome and incurs a second colour impression which is different from the first colour impression, detecting at least two images of the security document in front of the display device for at least two different viewing geometries, in that at least one first image is detected for a first viewing geometry and a second image is detected for a second viewing geometry which differs from the first viewing geometry, evaluating the at least two images detected, wherein, during the evaluation of the at least two images, a check is made as to whether the images comprise the first and the second partial image portions (101, 102) in such a way that the first image and the second image can be supplemented to form one total image, and from the total image, with a human observer, on the basis of a colour mixture, a monochrome colour impression is incurred, which is different from the first and second colour impression, and deducing therefrom a verification decision, wherein the verification result is dependent on whether the total image incurs, or not, a monochrome colour impression which differs from the first and the second colour impression.