Fundamental to the experience are the specifics of the paper, its physical characteristics. While colors are crucial in their own way, the look and feel of the paper can tell your audience a lot about your brand before they read a single word. At the same time, it can also do the opposite. The experience of paper is influenced by its basis weight, or basis, among many other factors.
Paper basis weight is expressed in the U. Basis weight is what the paper would weigh in a full uncut ream in an accepted standard size basis size for a given use. For example, if you purchase 60 lb. Adding to the confusion, foreign paper designations use the metric system, which sets its basis weights based upon the weight of one square meter, expressed in grams GSM.
Check out the basis weight chart below to see a rough conversion between metric and American basis weights. Paper Conversion Chart. Paper thickness, or caliper, is impacted by many factors, including finish and basis. Simply put, paper without a finish for a given basis weight will have a higher caliper or thickness, than those with a finish. So, a 60 uncoated offset will typically be thicker or feel more substantial than a 60 gloss coated sheet.
For example, a 7- or 8-point stock will measure. Typically, thickness or a point measure is most relevant when talking about mail. And if sheets of Cover paper 20 x 26 inches weigh 65 lbs, then a ream of this paper trimmed to tabloid size would be marked as 65lb. Based on experience from using a small subset, they have a pretty good idea of what to expect when reaching for a 24lb Bond versus a 60lb Cover versus a lb Index. Each media often serves a specific purpose. Place your cursor over each image for a short explanation about each paper type.
Bond Paper. Book Paper. Bristol Paper. Cover Paper. Index Paper. Offset Paper. Tag Paper. Text Paper. Fortunately, there is a metric measurement that is nearly always displayed alongside the U. Basis Weight. The metric measurement sometimes called grammage is the actual weight of one sheet of media cut 1 x 1 meter square. Finally, you can always measure the thickness of a sheet of paper using a caliper. The stock level in the head box directly affects the thickness of the stock being laid onto the forming screens and the thickness of the end product.
Because there are normally variations in the thickness of the pulp stock as it is laid onto the forming screens, excess stock must be laid on to ensure that a minimum thickness is maintained. Since the finished product is measured by weight, this figure is referred to as the "basis weight" of the product. Basis weight is defined as the weight of sheets of paper cut to a standard size, usually 17" x 22" for bond paper, 25" x 38" for text, offset, and coated papers, and 20" x 26" for cover papers.
Magnetic flowmeters are often used to measure the flow of pulp stock into the head box. Since pulp stock tends to be a noisy measurement with a magnetic flowmeter, long damping times are traditionally used to smooth the output of the meter. Unfortunately, this results in slow response from the meter and wasted pulp stock because the level in the head box must be kept high to avoid gaps or voids in the final product. While reducing the damping in a pulsed DC magmeter will result in quicker response, it can also result in a noisy signal.
The noisy signal causes the valve controlling the pulp stock level in the head box to chatter which effects level control in the head box. The resulting thickness or "basis weight" of the end product is then compromised. Yokogawa's unique simultaneous dual-frequency excitation method and optional enhanced dual frequency excitation method can offer benefits in this application which can result in tighter control, faster response, more end product per batch, greater profit and a direct cost savings to the customer.
In slurries, such as pulp stock, noise is generated when "pulp fiber" collide with the electrode. The collision displaces a thin oxide layer present on most electrodes, and electrical noise is generated when the exposed metal re-oxidizes. Slurry noise has its greatest magnitude at low frequencies, so conventional magmeters using low frequency DC excitation 6.
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