55 ILCS 5/3-5010
Every recorder shall, as soon as practicable after the receipt of any instrument in writing in the office, entitled to be recorded, record the same at length in the order of time of its reception, in well bound books or computer databases to be provided for that purpose. In counties of 500,000 or more inhabitants, the recorder may microphotograph or otherwise reproduce on film or store electronically any of such instruments in the manner provided by law. In counties of less than 500,000 inhabitants, the recorder may cause to be microphotographed or otherwise reproduced on film any of such instruments or electronic method of storage. When any such instrument is reproduced on film or electronic method of storage, the film or electronic method of storage shall comply with the minimum standards of quality approved for records of the State Records Commission and the device used to reproduce the records on the film or electronic method of storage shall be one which accurately reproduces the contents of the original.
55 ILCS 5/3-5010