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Of all wood pulp papers, only paper made of #1 sulphite is considered a “fine” paper and can be identified with a watermark.back to top ACID FREE FORMULATION: Paper which has no acid or residual acid-producing chemicals is called “acid free”.This is done by incorporating a special marker into the watermark.
The watermark generally will identify the manufacturer, the brand name and the amount of cotton fiber, if any, in the sheet.
Through the use of a special roller called a “dandy roll”, the watermark is impressed inside the paper early in the manufacturing process.
back to top SULPHITE: Wood pulp is processed into sulphite, which is then used to manufacture various grades of paper.
It is more economical than cotton fiber however, it is also less durable and more acidic than cotton fiber.
Papers that are “acid free” will resist yellowing and disintegration longer than sheets that are not acid free.
This is particularly true as the percent of wood pulp in paper relative to the amount of cotton increases, since cotton fiber papers are less likely to disintegrate or yellow than papers made with all or part wood pulp.back to top COTTON FIBER: Cotton is one of the strongest and most durable natural fibers known to man.Papers manufactured from cotton fiber will last longer and hold up better under repeated handling and various environmental conditions than paper made from wood pulp.The most common blend is made of 25% cotton and 75% wood pulp.Other, less common blends include 50% and 75% cotton fiber, the balance of each being made up from wood pulp.A watermark may be centered or localized on each sheet, or more commonly it is a random mark.A random mark may be centered, but most often will appear in various positions from sheet to sheet.There are different grades of sulphite, depending upon how much processing has gone into making the pulp.Processing includes breaking the fiber down to very fine pieces and bleaching the natural color out of the wood to attain a high level of whiteness.Generally, given reasonable care, a customer can expect one year of usable life for every 1% of cotton contained in the sheet.Typically cotton fiber papers are made of either all cotton fiber (100% cotton) or a blend of cotton and wood pulp.