The published articles are meant to primarily educate the students in printing to supplement their knowledge in the field of Printing. These are not simple Glossary of printing terms, but to the extent possible every term has been explained in brief so that it can be of some use to the students who appear in some sort of examinations and interviews.
I served the Printing Industry for over 40 years
in various capacities, a major part in an Security Printing Organization. In order not to waste the printing and paper related knowledge which I gained over years, I decided to keep them in public domain for the reason stated in prepara. Most of the illustrations - over 90% - have been generated by me to explain the terms suitably.
While I am not sure to what extent the published content will help, if the content is going to be of use to some one in some manner, I will be greatly satisfied.
Your views may be sent to me (
nrj_1945@yahoo.com) for my record and correction wherever needed.

TOTAL NO OF PRINTING TERMS

POSTED TILL NOVEMBER, 2012

- Over 400 terms-

Click on this line to read from 'A'

Sunday, October 15, 2017

Guide to printing students - 12

Guide to printing students
-Few objective Questions and answers- 
Written by : N.R. Jayaraman
Pre note:-
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 Please note that these are not to be published by anyone for commercial purpose without the written permission from the author since the theme and illustrative examples have been compiled exclusively by the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.

63) What is Aqueous Coating?
It is a water base clear coating which is done on the printed stock not only to protect the print, but also enhance the appearance. This is done through the paper coating machine and the clear coating provides high-gloss surface that deters dirt and fingerprints and improves the durability of printed material as they are handled. It also looks beautiful on brochures, catalog covers, and stand-alone flyers.

64) What is banding defect in the printed image?
This is a print defect that sometimes appear in halftone screen tints when the print is taken on a laser printers, image setters, or plate setters. The defect will appear on the print in the form of parallel streaks on the images.

65) What is a Caliper and its use ?
It is a tool used to measure the thickness of the paper stock and its value expressed in terms of microns (millionths of a meter). Variation showing ± 5% in the figure arrived at different places with different calipers is normally acceptable in international standards. 

66) What do  CMYK represent ?
It is related to the sequence of colours used in four colour printing process. It indicated the primary colours such as Cyan, Magenta, Yellow and Black. 

67) What is Colour separation process in printing ?
It is a Graphic arts reproduction process of converting the coloured originals into printable plate for the printing machines. Normally the coloured originals are converted into three or four colour printable plates using colour filters and halftone screen in different angle. In this process the multi tonal coloured originals are converted into tiny bit of dots of varying sizes to match the shades in each colour When the thus separately converted plates are printed using CMYK or CMY colours one over the other, the resultant image will match the colour original. This is called colour separation process.

68) What is referred as Dot gain in a printed sheet ?
It  is a  phenomenon in printing which cause tonal value increase to make the print appear darker which occurs ink mismatching to the stock of paper is used for printing and the base oil in the ink is absorbed by the paper showing the printed dot appear slightly bigger than the image on plate. Such an appearance of  ink dot -enlarged appearance-  due to absorption by the paper is called dot gain. 
69) What is Duo-tone printing ?
Converting one colour or black and white original into two coloured original in printing by use of two different plates made with two halftone negatives-each varying by 15% in angle. Such printed images will appear as if the original was also two coloured one. This is called Duo-tone printing process. 
  
70) What is the difference between Halftone dots and Elliptical dots ?
While reproducing an original by printing process, the original need to be first converted into printable form by splitting the various shades in the original into varying sizes of dots. This is done by reproducing printable plates using halftone screen. In this conversion process, the conventional halftone screen produces circular dots of various sizes. Similarly the other special halftone screen used is Elliptical screen which produces the dots in the shape of elliptical dot pattern and not circular dots. Some of the originals, especially the black and white and Duo-tone originals give better print effect when they are printed using elliptical screen. 


71) What is short and Long grain paper?
During paper manufacturing process the paper whose fibers run parallel to the long dimension (running length) of the sheet is called long grain paper and the paper whose fibers run parallel to the short dimension of the sheet is called short grain paper.
72) How important is the grain direction in printing ?
Grain direction i.e cross-grain direction and long-grain direction is an important consideration while printing multi colour reproduction especially in sheet fed offset print process since the sheets will have to maintain true dimensions for perfect registration. It is the tendency of the paper fibers to absorb water from the atmosphere if their moisture content in them is less to the room temperature. Normally the sheets expand in width, but not in length. Because the direction of greater dimensional change will be in the cross-grain direction, long-grain paper (fibbers floating along the running length) is generally preferred for offset printing process to ensure that the dimensional stability of paper is maintained for perfect registration of colours. However for single colour work the grain direction is not a concern. 
To be continued.............13

Saturday, October 7, 2017

Guide to printing students -11

Guide to printing students
-Few objective Questions and answers- 
Written by : N.R. Jayaraman
Pre note:-
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.

58) What is  Direct imaging and Direct printing?
Direct imaging is a new technology that directly transfers the digital image to press plates like Letterpress, Offset, and Intaglio printing using laser beams.

Direct printing which is technically called Digital printing is a process in which the image is created on the computer and transmitted directly to the output device i.e the printer to print on the paper.

59) Explain Direct Imaging process
This process known Copy to Plate or CTP is a new technology by which the printing plates needed for the printing machines are prepared directly using laser beams. The advantage is improved resolutions of the images and print quality as well. Since the laser records the images onto the plate exactly as per the digital files stored on a computer, the print quality will be excellent. Moreover the manual steps of conventional prepress work such as producing films, preparing the films for plate making, making plates, and mounting and registering plates on the press etc are all eliminated. There are equipments available which can be attached with the offset presses to store the spool of special plates meant for direct imaging. As soon as the new plate is made ready by direct imaging process, such plates are automatically fed onto the plate cylinder from the spool. This reduces the make ready time drastically. 


60) Explain Direct Printing (Digital Printing ) process
This is a process in which the image is created on the computer and transmitted directly to the output device i.e the printer to directly print on the substance. No pre press operation including making of negatives from thee composed matter , assembling etc, or plates are required. The prints are taken combining both text matter and the photographs including the colored ones, using Liquid ink-jet, wet/dry toner systems, solid ink-jet, thermal-transfer etc. The equipments also aid in saving space, cut down production time and most suitable for small and immediate jobs. Determining when to use digital printing instead of a traditional printing process is highly dependent on the number of prints needed as well as the production speed of the output device.

One important advantage of Digital printing is the possibility of printing variable Data using information obtained from the database or external file. The texts and graphics can be changed on each sheet without stopping or slowing down the press. For example, personalized letters can be printed with a different name and address on each letter. Digital printing is also a very flexible process that provides a great opportunity for creativity as it allows the press to make the desired changes without prepress operations. By digital printing even very small quantities can be printed in the shortest time. The digital printing machine normally uses only four colour cartridges with whose combination the multi colour printing is carried out.

61) What is Bar Code Printing?
A bar code is an optical machine readable representation of data relating to the object to which it is attached. Bar codes are made up of a series of narrow and wide bars that can be scanned using a photo-type of sensor. Each firm can generate their own coded bars with bar code generator. The pattern of each bars in the code represents a character. This sensor reads the bar code, turns it into a signal which is then sent to a computer or network. All bar codes commence with a unique start character and concludes with a unique stop character. This scanning method calculates the measurements between each bar and space and translates those measurements into characters for authentication

62) Which of the important factors  influence higher percentage of rejection during printing and how to control them?
The following three factors are some of the most important reasons for higher percentage of rejections of the printed sheets:

(a) Basic paper problem
Defective paper lots causes higher rejection due to reasons like fluff ( White spots on the printed areas ), creasing of paper, mis register due to expansion and shrinkage of the paper while carrying out printing. Paper expansion and shrinkage are due to atmospheric changes. Such cases are to be seriously taken up for corrective action with the suppliers. Subjecting the paper to proper storage condition till the printing is completed is another corrective action.

(b) Blank sheets getting torn during feeding or printing, malfunction of the machines etc.
Careful handling of the sheets and proper adjustment of machine settings during machine run will reduce its tally. Periodical maintenance of the machines keep the machines in fit condition. Proper oiling and greasing of the machine by the machine crew will also help. Strict supervision on procedures to be followed is needed.

(c) Printed sheets showing colour variation, mis register, wrong prints, white spots  etc.
Proper ink flow settings, machine adjustments, careful and frequent checking of the printed sheets taken out from the delivery pile, random checking by the supervisors besides regular checking by the workers during  various printing stages and taking immediate corrective action will reduce the wastage. 

Where the press can afford deployment of online inspection equipments like sheet inspection gadgets which display the error spots on check screen instantly as the sheets are delivered will also help in detecting the exact places of errors instantly to take corrective action. Strict supervision on the work needed.

The wrong prints are generally noticed in numbering process if the printed sheets carry numbering. Therefore  careful and frequent checking of the printed sheets for wrong  numbering and taking immediate corrective action will reduce the rejection percentage.
To be continued.............12

Thursday, October 5, 2017

Guide to printing students -10

Guide to printing students
-Few objective Questions and answers- 
Written by : N.R. Jayaraman
Pre note:-
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.

52) What is the standard norm normally followed for calculating the machine life?
  • 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.

53) What is the standard thickness of Offset and Intaglio printing machine Blankets ?
The standard thickness of Offset Blanket ranges from 1.65 mm to 1.70 mm while the standard thickness of Intaglio blanket is 0.5 mm. While the above are standard ones, machine specific thickness blankets are also made available by the manufacturers to suit their machine configuration.


54) How will you work out the weight per ream of paper ?
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
  • or
    Length of paper in CM x Width of the paper in CM x500 x GSM / 100000 x 1000

55) What is GSM and how will you work out the GSM of paper ?
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 .


To find out the GSM of the paper the following formula can be used:

1000  x  100000
----------------------------------------------------------------------------------
Weight of paper in Kg  x   length  x  width of paper in mm  x   500


To find out the weight in Kg of the paper the following formula  can be used:

GSM  x  length  x  width of paper in mm   x   500
------------------------------------------------------------
1000 x 1000000

56) What is fixed cost in printing industry?
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.

57) What is Ghost image on print?
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. 
To be continued.............11

Wednesday, October 4, 2017

Guide to printing students - 9

Guide to printing students
-Few objective Questions and answers- 
Written by : N.R. Jayaraman
Pre note:-
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.


49 ) What are the common security features found in a Currency or Bank Note ?
The following are the commonly embedded  security features in the Currencies and Bank Notes all over the world. Over 95 % of the  world Currencies and Bank Notes contain only these features in addition to one or two specialized patented features developed as country specific feature. 
  • Water mark : It is a recognizable image or pattern in paper that appears lighter or darker compared to the colour of the paper on which it has been embedded. When viewed with a light from behind the paper, due to paper density variations the water mark will be visible. A watermark is made by impressing a soft metal stamp or dandy roll onto the surface of the paper during manufacturing of paper. 
  • Guilloché design : It is an ornamental pattern formed with several curved bands that interlace to repeat a circular design. They are made with a geometric lathe machine specially constructed for forming the design elements. It has several hundred gears that shapes up the design. 
  • Micro printing: Extremely minute delicate text, invisible to naked eye as text. The micro printing is most often used on currency and bank cheques. The text can be seen only when viewed by powerful magnifier
  • Colourshift thread : Specially printed or OVD patched color changing threads inter laced in the paper. They appear in different color when viewed at a different angle. The color of the thread does not actually change, but the angle of the light to the viewer's eye changes and thus creates the change in color.
  • OVI : Called Optically Varying Ink  is also colour changing ink that show different colour when viewed in different angle. This ink is generally printed by Intaglio print process on the Currencies and Bank Notes.
  • Security Thread : There are two kinds of security threads. One of them is thin aluminum coated and partly demetalized Polyester film thread with Micro print  which is embedded in the security paper. The other is as mentioned above- colour shift thread.
  • See through design:  Banknotes are typically printed with perfect registration of a design whose design elements are split and placed as one half on each side of the sheet. Only a part of the design will be seen on one side while on the other side the other  part of the same design will be printed. When the sheet is held against light and viewed, the split images on both sides will appear as perfectly registered thus showing full design element.
  • Intaglio print: Embossed or relief effect of the print which can be felt by moving the finger over the printed image
  • Dry offset print : The background light coloured design elements in different patterns, lines, criss crosses and ornamental designs.  
  • Fluorescent ink : Used for numbering which fluoresce when viewed under UV light 
  • Thermo chromatic ink : Ink which changes color or visibility when rubbed, usually by the fingertips. 
  • OVD patch: Generally found in the plastic and polymer notes. The insertion of an optically variable device (OVD) created from diffraction gratings in plastic as a security device inserted in banknotes.
50) What is the international standard accepted  for calculating the production norm ?
As per the international standard, the production norms are calculated based on the following conditions: 
  • The press work for 8 hours per shift with minimum half an hour lunch break. 
  • Standard shift being 2 shifts per day.
  • Press work for 365 days minus the general holidays and weekly offs on Saturday and Sundays. 
  • The machines are put to 'x' no of days for preventive maintenance per annum when no production will be done on them.
  • The calculation is based on printing the maximum size sheet fed on the machine.
51 ) What is the acceptable standard formula followed for calculating the production norm ? 
When the manufacturer says that the machine can runs at a maximum speed of 10000 sheets of A2 size paper an hour it will give  an average output of 'X' no of  sheets per hour taking into consideration machine stoppages for various reasons and general shift conditions. Therefore the output per year per machine would be worked out in the the following manner
  • Optimum speed of 10000 sheets per hour will to be worked out at the rate of  75 % i.e 7500 sheets per hour considering the  full pick up of speed after each stoppage for some technical reason or the other. This is the standard practice followed internationally.
  • 8 hours shift to be worked out as 6.0 hrs (75 %) giving 2 hours for shift start up, shift end cleaning, technical problems  and make ready etc.
  • 365 days a year to be worked out as 290 (80 %), the rest being no production days due to various intervening holidays and other reasons.
Therefore the optimum output based on above could be:
  • 7500 sheets x 6  hours a day x A2 size paper x 290 days = 13 to 14 millions max per shift, per machine
  • 7500 sheets x 6 hours a day x 10 ups in A2 size x 290 days = 140 million pieces max per shift, per machine
  • 7500 sheets x 6 hours a day x 20 ups in A2 size x 290 days = 280 million pieces per shift, per machine
  • 7500 sheets x 6 hours a day x 40 ups in A2 size x 290 days = 560 million pieces per shift, per machine
Based on the above formula each press work out their target and form their production norms. 
To be continued.............10 

Sunday, October 1, 2017

Guide to printing students- 8

Guide to printing students
-Few objective Questions and answers- 
Written by : N.R. Jayaraman
Pre note:-
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.


44) Two major divisions of printing processes exist, What are they ?
  • The printing is divided into two groups. They are Security printing and Non Security printing. 
  • Printing the images without carrying overt and covert features in design element which are anti copying in nature is called Non Security printing and printing the images incorporating several kinds of overt and hidden covert features which are anti copying in nature is called Security printing. 
  • Printing text books, magazines, news papers, leaflets, pamphlets, posters, certain labels, coupons, advertisements, catalogues, stickers etc are covered broadly under Non Security printing. 
  • The Security printing covers printing of Bank Notes, Currencies, Stamps, Stamp papers, Brand protection Labels and cartons, various money Coupons, Licenses, Passports etc
45) What is Money? How did it emerge ?
Money is a medium of payment consisting of metallic coins, paper money and withdrawal documents. A Banknote or Currency is a type of negotiable instrument or a promissory note and form part of money. The birth and growth of money in the form of Paper Currencies and Bank Notes stemmed millenniums ago from the primitive barter, a system through which goods in need were exchanged for other goods since no payment system in the form of money was in vague anywhere in the world.

46) What is the difference between Currencies and Bank Notes?
  • There is no difference between a Currency and  Bank Note except that they are issued by two different agencies independent of each other. Both guarantee the values as indicated on those instruments while they are exchanged for some consideration. 
  • A Banknote is often known as a bill or paper money and issued by the Central Bank or Treasury on behalf of the legally elected Government of a country or state. 
  • Each and every Bank under the Central Bank cannot issue the Bank Notes as they are not authorized to do so. Only the Central Bank which organizes the printing of Bank Notes arrange  for the circulation of the money through the agency banks working under them. 
  • Bank Note is a kind of negotiable instrument such as a promissory note and the value indicated on them is payable to the bearer on demand as assured by the bank as it has been issued by it on behalf of the Govt of the state. 
  • The Bank Notes contain the signature of the head of the Central Bank called Governor of the Bank in many countries. 
  • On the other hand the Currency note is also another form of the paper money issued along with the metallic coins called money. 
  • The Currencies are issued by the Government themselves guaranteeing the value indicated on them. It carries the signature of the Finance Secretary of the State. But the same Currency along with metallic money called coins are also not directly circulated by the Government but are transacted only through the Central Bank and their agency banks. 
  • Therefore a Country can have both Currency note and Bank Notes besides coin.
47) Who invented the Bank Notes and Currencies ?
The Chinese jiazi banknotes are generally considered to be the first paper money in history, entering in use around about 960 AD. The first European banknotes were issued in Sweden in 1660.
 
48) What types of common machineries and equipments are used for the production of security printing documents including Currencies ?
Some of the common machineries and equipments available for security printing include the following:
  • Dry Offset : To print base tint design elements on both sides of the paper. The Dry Offset machine also is supplied in the form of perfecting machines to print the design elements simultaneously on both sides of the paper in one pass.
  • Intaglio: To print relief images on the paper 
  • Cut pack: To process the numbered sheets into bundle of 100 notes by automatic process
  • Super Numerota : To print serial numbers on the printed notes in sheets
  • Nota sort : To automatically sort out the good and bad notes after the printed sheets are cut into note size
  • Nota Numbering : To automatically number the single good notes sorted by the nota sort machine
  • Random Numbering: To automatically number the serial nos of the defective notes which were fed into the memory so that they can be removed and processed to replace the defective notes in a bundle.
  • Guillotine : Manual processing to cut the numbered sheets into bundle of notes
  • Colourtronics : To online check the shades printed and to correct the ink feed on the machine
  • Sheet inspection machines : Automatic checking of the printed sheets for defects. This replaces the manual checking for the said cause
  • Nota save : Automatic online checking of the printed sheets for printing defects. This helps the operator to quickly correct the defects in printing.
  • Computer to Intaglio plate: Engraved polymer plates to make Intaglio printing plates. This replaces more than 75% process done manually thus saving time and giving perfectness.
  • Track and trace : A machine system fitted on all the machines with whose memory of the printed sheets, the missing sheets can be traced to exact point and also give exact figures of printing in each process thereby updating the accounting of printed, blank and defective sheets.
to be continued...............9