why aren't they suitable for professional mounting? are they not archival?
Thank you for your enquiry.
The Set of 60 x Ready cut mounts 280 x 225mm are cut from Daler Rowney Sheet Studland Antique White 1400 micron which is a Cream Core Mountboard.The core is made from virgin wood pulp with a characteristic pale ivory colour. Each board is alkaline-sized and pH neutral and meets FATG specifications for standard mountboard. Manufactured in the UK. lifespan.
Though these are the most popular type of mountboard used globally, but the cream core mounts do tend to yellow with age, so a conservation quality mount is something to be considered.
Daler Rowney Mountboard Conservation – is a truly professional Conservation board, which conforms to the Fine Art Trade Guild requirements for Conservation (level 2). The core is made from alpha cellulose fibres, featuring a soft, natural, white colour that will remain white. Each board is alkaline-sized, acid-free and calcium carbonate buffered for enhanced durability and longevity. Being conservation quality, boards are lignin-free with no optical brighteners. Cover papers are colourfast, resilient and bleed resistant. Manufactured in the UK.