 This was possible because linen is strongly resistant to dyes but cotton is not.Rogers claimed that the repair had gone undetected because it was expertly done; there was no record of it; none of the STURP team were textile experts; and the area had not previously been a major focus of any major Shroud researchers' attention, because it was outside the image area.Rogers claimed that under the microscope he could see the undyed linen fibers, the cotton fibers, and the dye on the cotton fibers.