The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
How we test print quality and speed
Quality and speed for different types of documents.
How we test scanning quality and speed
Quality, speed, and ease of scanning different pages, including text, colour pages and photos as well as scanning small objects. A scanner has to scan an A4 photo in 20 seconds or less to score five stars for photo scanning speed.
How we test copying quality and speed
Speed, quality and ease of copying different types of pages with and without using a computer.
How we test ease of use
Ease of use, including printing, copying and scanning where relevant.
How we test printing costs
How cheap or expensive the printer is for ink/toner costs per page. More stars means cheaper prints. Costs are based on our occasional printing test - printing black text and colour pages, leaving time between prints and turning the printer off between uses. Printers with no star rating were tested prior to our occasional printing test.
How we test durability
Our research shows a typical printer lasts for 13 years, and printouts may last far longer. Durability and maintenance are the assessment by our technicians of the build quality of the printer and how easy it appears to maintain. For our light resistance rating, we print colour test sheets on 80gsm glossy Xerox photo paper using the printer brand's original ink/toner and place the test print in a calibrated light box, which simulates approximately one year in direct sunlight. More stars means less fading. You should expect different results for third-party ink/toner. If you choose a location less in direct sunlight it will greatly reduce the risk of fading.
How we test power use
For energy, it's based on power use when the printer is turned off, in standby and when idle, just after printing.