The origin of calendars
Calendars show in big letters the date and there are also predictions about the solar terms, everyday luck,etc. The real calendar appeared about 1100 years ago in the first year of Yong zhen when Emperor Shunzong of Tang was on the throne. There was almanac in the imperial palace. At first there was one page for each day recording the great events across the nation and in the court as well as the words and deeds of the emperor. The almanac has 12 volumes. The number of pages for each volume is the same with the number of days in each month. Each page marks out the number of days and the dates. Later, contents such as the dates, sexagenary cycle, climate and other natural phenomena of a season are written on the above in advance while the blank at the bottom are left for recording events, which is very similar to the desk calendar nowadays. At that time, the eunuchs serving the emperor records the words and deeds of the emperor in the blank space and after checked and approved by the emperor at the end of each month, it is passed onto the historiographer for filing. This was called calendar, which later serve as the evidence that historiographers use to write the National History.
Later, the ministers at the court follow the examples and made the calendars of their own. And the development of calendars into various forms such as the wall calendars and the desk calendars happened only a century ago. With the development of time, though calendars vary in forms and designs, they still kept the pattern of the ancient calendar.
The classfication of calendars
Calendars include the lunar calendars and the solar calendar. The calendar year of the solar calendar lasts for a tropical year. The now internationally used the Gregorian calendar is a kind of solar calendar and it is briefly referred to as the solar calendar. The calendar month of the lunar calendar lasts for a lunar month. A calendar year compromises 12 lunar months, with a 30-days month of the lunar calendar or a 29-days month of the lunar calendar. The Islamic calendar is a kind of lunar calendar. The average calendar year of the lunisolar calendar lasts for a tropical year while the calendar month of the lunar calendar lasts for a lunar month. Since 12 lunar months differs greatly from a tropical year, so leap month is arranged in the lunisolar calendar. Thus, this kind of calendar conforms to the phase of moon as well as the periodic motion of the earth around the sun. The traditional Chinese calendar is a kind of lunisolar calendar.
The popularization of calendars
Later, the ministers at the court follow the examples and made the calendars of their own. Still later on, as the calendar become popular and homely, people printed the sexagenary cycle, climate and phenology in a lunar month, solar terms, and white days on the almanac all on the calendar and left blanks for recording events. And the development of calendars into various forms such as the wall calendars and the desk calendars happened only a century ago. With the development of time, though calendars vary in forms and designs, they still kept the pattern of the ancient calendar.
The production process of calendars
The finishing of calendars, monthly calendars, desk calendars and wall calendars includes two parts: the making of covers and the making of holders.
The making of covers can be divided into the following three steps:
First, the uv of the cover, which refers to the coating (spouting or imprinting) of a layer of colorless transparent painting. The thin and transparent layer formed on the surface of the cover could be used to protect the printing content of the desk calendar. It also has the function of beautifying the cover, make the printed matter glossier and look better. The cover uses embossing, namely an intaglio and a relief printing plate clamp the cover and under certain pressure, images or patterns similar to the relief printing plate appear on the surface of the cover, which makes the printed matter look embossed. Coating covers refers to the process technology of coating the plastic film with adhesive and bonding the film with the cover by heating and pressing. After being coated with a film, the cover is smoother and glossier. The color looks firmer and the image-text looks brighter in color and full of dimension. It also has the function of waterproof, anti-fouling, wear-resisting, folding resistance and corrosion resistant. These are the basic steps of making covers.