@Amy
It depends on how flat the surface will be for your collage. The scanners mentioned above are using CIS technology so they can only scan something that's in direct contact with the glass.
Let's say you use cardboard that's not as thin as paper, e.g. such as those backing for some writing pads, and you paste it on another paper. The areas closest to the outer boundary of the cardboard will be blur because they are not in contact with the glass.
For uneven surfaces, you have to find scanners that use CCD technology.
@Amy
It depends on how flat the surface will be for your collage. The scanners mentioned above are using CIS technology so they can only scan something that's in direct contact with the glass.
Let's say you use cardboard that's not as thin as paper, e.g. such as those backing for some writing pads, and you paste it on another paper. The areas closest to the outer boundary of the cardboard will be blur because they are not in contact with the glass.
For uneven surfaces, you have to find scanners that use CCD technology.