The photograph was taken at Hille Studio at 3452 S. Halsted in Chicago. Jacob J. Hille was at that address from 1891 until at least 1900 and probably later, which helps confirm this portrait could be in 1901. The only other possibility is this could be Trijntje’s 70th birthday portrait, May 2, 1902. But I tend to believe this portrait is more likely for their 50th in 1901. In either case, there is only a 6-month difference.
Dick Denker provided a Xerox of this photo to Dave Jordan after the 1988 Vanderkloot Reunion. It is unknown who has the original photograph. If the original can be found, a higher-quality image can be uploaded. If you would like to add information about this photo or provide a better scan, please contact Dave Jordan, a 2x great-grandson of Matthijs and Trijntje Vanderkloot. The Picture Reference Number is DJB47.