The weight of paper may be expressed as basis weight, ream weight, M weight, or grammage. Ream weight is the actual weight in pounds of 500 sheets of paper, regardless of basic size or grade. M weight is the actual weight of 1,000 sheets of paper. Because this is twice the quantity of a ream of paper, it is also twice the ream weight. Grammage is a metric measure similar to the basis weight of paper.
Paper is more water than fiber inthis section of the machine.
How white a paper is depends on how evenly it reflects all colors in the visible spectrum. If it reflects more blue than red and yellow, it will have a cool, blue tinge to it, making it appear brighter than white. A cool paper will appear brighter than a similar paper with a warm tinge. A cool or a warm tinge doesn't affect paper quality, but it does create optical impressions. For example, in color printing with blues and blacks predominating, a cool white sheet tends to brighten the colors.