Gsm means the weight per square meter. Usually the weight per square meter is not exactly accruate, it allows to be fluctuate within 4% more or less.
      The feeling of touching the paper is different because of the different technologies adopted in manufacturing. For example,the common wood board will become more tight in constructure if pressed. Thus the quality of the wood board is improved and the organization becomes difficult to be changed. The tracing paper in my company is more smooth compared with other paper of its kind which has not been put to additional processing. Therefore it is necessary to take the two factors of smoothness and transparency into consideration when we measure the quality of the paper.

Quality distinguish

      The following is some basic methods to be used in recognizing the quality of paper. Averageness,we can judge the averageness of the pulp by the light through the paper. Flatness,we can see the flatness of the paper both by vision and the touch by hand. Stiffness, we can judge from the drooping of the paper if we leave half of a piece of paper outside the margin of the desk. Tearness, we can tear the paper both from the horizontal and vertical so as to judge the pulp fabric length,water contain and paper toughness. The feeling by hand touching(hygrometer). Transparency, we can judge by vision.
      The quality of coated paper is judged by the averageness and thickness of the coating, the glossyness and smoothness of the piece of paper, also by the quality of image and print-out.

Check size and weight

      The size of the paper also has a standard error, the width of paper has a standard error of±0.4%, and the length has a standard error of±0.1%.
      Let’s cite an example, all the tracing paper between 60gsm to 65gsm is produced at the basic weight of 62.5gsm, there is a±0.4% standard error. So when we supply our customers the 62.5gsm tracing paper, all the weight between 60gsm to 65gsm are also standard. Other weight of tracing paper has the same principle in calulating the weight.

The foundation for price and quality comparison

      Let’s begin with the same weight xerox engineering paper. There are varies of quality levels of the xerox engineering paper even at the same weight. The neutral kind will not bring much erosion to the selenium drum because of its low level of acid. We can lessen the exchange frequency of the parts and make the engineering copier work longer by using the neutral xerox engineering paper. The light sensitivity materials and organic light conductive materials inside an engineering copier are frangible to acid. You know the parts and wear and tear of machinery can cost a lot of money.
      The second is the shortness of length and width of some kind of products,for example 880mm X 80m X 62.5gsm , its value is RMB 200 yuan, the price per meter is 2.5 yuan. Due to shortness of length, a roll only has 72 meters,and its actual value is only RMB180 yuan. For the xerox engineering drawing paper, 880mm X 150m X 80gsm ,the value is RMB 100 yuan, the value per meter is RMB 0.66 yuan. But in fact it only costs RMB 94.66 yuan because it actually only has 142 meters. If customers buy this kind of paper, it seems that they buy the cheaper products, the former is 20 yuan cheaper, the later is 5.6 yuan cheaper. But in fact they are cheated.

Improvement on customer's abilty to distinguish and protect

      Currently some suppliers adopt unjust methods, such as shortness of measure to decrease cost and price. The 150 meter long roll is purposely processed into 142 meters long, the 70 meters or 72 meters long roll aslo appears which should have been 80 meters long. If customers buy this kind of roll, they will lose at least RMB 6 to 8 yuan.
      We can weight the roll by the electron steelyard. When we calculate, we may apply the formula of “weight plus width plus weight per meter equal to standard weight, take the meter and kilogramme as unit, and the medium weight of the whole weight( for example take 62.5 gsm from 60-65 gsm, to the definited weight of 63 gsm and 80 gsm, we can directly take the figures into the calculation. The error is not more than 1% is standard, the error has more than 1% is not standard.
      Take an example, the xerox engineering paper of 80 gsm, its specification is , the detailed calculating step is to use the above formula and get 0.88m plus 150m plus 0.08kg and get the result of 10.56kg, then compare the 10.56kg with actual weight of the roll of which total weight is lessen by the weight of the inner core. If the difference of the comparision result is more than 1% is not standard, the difference is within 1% is standard.