Paper money needs to he designed and made in such a way that it is very difficult to forge. Banknotes have extremely complicated designs, with pictures and backgrounds made up of very fine lines and patterns. These are printed from hand-engraved steel plates. The notes are also printed on a special type of paper, which is hardwearing and has a strip of plastic or metal embedded in it.
The banknote design typically starts with the compiling and reviewing of historical information, images, Thai patterns, and other elements related to the main theme to be depicted on a banknote. In early days, due to the limited availability of equipment and tools, each new banknote design was to be hand - drawn elaborately in color. To this day, banknote designers still need to possess both artistic skillfulness and computer expertise to create the best design and origination for a banknote. In designing banknote, factors to be considered are:
- Cultural identity
- Technical limits
- Counterfeit deterrence feature
Having obtained the design, hand engraving of metallic plates and drawing of design of the original plate is performed by highly skilled and experienced specialists so as to achieve the high degree of precision, tonal variation and perspective requirements for banknotes. The background patterns, formerly etched by machine, are now created by computer programs.
1) Offset Printing?
The background design is printed first by dry offset on a specially designed printing press that is able to print high-precision color patterns on both sides of the sheets simultaneously. This makes it possible to produce perfect front and back registered designs or see through designs when viewed against transmitted light, one of efficient techniques to discourage counterfeiting.?
2) Intaglio Printing?
This process is used to add the portrait of H.M. the King and other raised prints on the front of the note. The image to be printed is inscribed into the plates. The inscriptions are filled with ink, and excess ink is wiped from the plates. Heavy pressure is applied to transfer the ink from the plates to the pager, leaving the surface slightly raised. This process gives banknotes a tactile feel to the touch, proven to be very effective in counterfeit deterrence.?
3) Letterpress Printing ?
Every printed sheet is carefully inspected. The good sheets are sent to printed serial number and signature by letterpress method, while imperfect or bad sheets are taken out of the system to be duly destroyed. The printing machine also has electronic numbering control to protect from miss - printing the numbering. This type of control helps prevent the repeat of numbering printed on each banknote of the same category.
Printed Sheet Inspection ??
The bank sheet then passes through a quality inspection and verification process that is one of the most important steps of the entire banknote production process. The inspection process is a process that screens good quality, partially damaged and mis-printed bank sheets from each other. Also, the quantity of sheets produced is assured by counting and verifying after finishing the inspection process.
The inspection and verification process is a process of screening the bank sheets into 3 categories;
1. Good quality sheet are those where every individual banknote has met the quality standard, which are then separated into the "good numbering" printing category.
2. Partially damaged sheets are those that most parts pass the quality standard. This set will be separated into the "partial numbering" printing category.
3. Bad sheets are those that do not pass the quality standard. This set of banknotes is sent to be destroyed and the number of replacement sheet is carefully matched to the number destroyed.
After serial numbering, the 100 % good sheets move on to cutting and packaging. Partially good sheets are cut, and defective notes are sorted out and replaced by special notes before being shrink - wrapped for delivery.