Guide to printing students -10
Written by : N.R. Jayaraman
The articles are meant to help the students gain knowledge and effectively compete in the interviews and nothing else. Please note that these are not to be published by anyone for commercial purpose without the written permission from the author since the theme and illustrative examples have been compiled exclusively by the author for the benefit of the student community. THIS WILL BE PERIODICALLY PUBLISHED.
- As per the manufacturers norms: 8 hours single shift x 290 days x 20 years which is 46,400 hrs. Once the machine works for 46,400 hours thereafter the the optimum working machine life guaranteed is over and the book value is considered to have become Zero.
- As per the Government (Indian) norms : 8 hours single shift x 290 days x 30 years which is 69,600 hrs thereafter the the optimum working machine life guaranteed is over and the book value is considered to have become Zero.
To find out the weight of paper per ream the following formula is used:
Length of paper in inches x Width of the paper in inches x GSM / 3100
Length of paper in CM x Width of the paper in CM x500 x GSM / 100000 x 1000
GSM means grams per square meter (gsm), which is the basic weight of the paper used. In metric system the mass per unit is expressed as GSM. In other words, a square meter of a specific type of paper will weigh a certain number of grams. The GSM indicates how dense the paper is and help the printer decide suitable paper for suitable job. The general principle is the higher the GSM the thicker the paper will be.
GSM also help in calculating the weight of a ream of paper so that the cost of the paper can be worked out as the paper is always supplied in weight and charged accordingly. The GSM is determined by weighing a known size of paper after conditioning the sample for 24 hours in ideal press room condition having 23°C temp and 50% Rh .
55 A ) You know the GSM, the net weight of the reel of paper and the width of the paper. With these inputs how will you calculate what is the total length of the paper in a reel of Paper ?
Costs that remain constant regardless of how many no of sheets are printed for a job. For example the costs incurred on Copyright fee, authors fee, preparation of manuscripts, copy writing and editing, % overhead to be charged, photography and designing etc which in effect are one time invested cost. Irrespective of how many copies are printed, those costs does not change.
Faint image seen on a printed sheet where it was not intended to appear may be termed as Ghost image. The Ghosting occurs when the printed ink film excessively penetrates to the back side of the same sheet thereby disturbing the appearance of the backside printed image and vice versa especially where halftone images appear. One of the major reasons for this defect is use of thin paper, excessive penetration of ink into the paper due to defective ink matching to the paper for which it was intended, fountain solution emulsifying the ink in wet offset printing etc.