1. Gang Runs: Where the print runs , colors and also the sizes are same, they are clubbed into one in a properly laid out fashion (layout) and printed in order to utilize the machine effectively and to reduce wastage of paper. This is called gang run. On completion of printing the sheets are trimmed to actual size to separate each work. Generally the designs that have less colors or line work are combined and printed. Multi color work is not combined and printed as the color adjustment to various jobs can not be achieved in this pattern of printing.
2. Ghosting: A faint image appearing on a printed sheet where it was not intended to appear may be termed as Ghost image. Sometimes the Ghosting also 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 especially where halftone images appear. Though no of reasons are attributable to this problem, the major reasons for this defect is thin paper, excessive penetration of ink into the paper due to defective ink, fountain solution emulsifying the ink in wet offset printing thereby causing ink to penetrate the paper, and blanket slipping etc. In a way even the doubling effect comes under this category. Properly cleaned and maintained presses and the use of high quality ink can help prevent ghosting. Adjusting the layout itself can also help in the prevention of ghosting. If you have a layout that incorporates both areas of heavy ink coverage such as large, bold headlines or reverses and areas of lighter coverage there is potential for ghosting on the back side of the sheet due to ink seepage. Therefore in such cases the layouts may be made in such a manner that the images do not appear on the back sides of the sheets below heavy text or image printed front side matter.
3. Gloss: The shiny surface of the paper called gloss can be derived in two ways. By running them between two polished stainless steel rollers at the end of the paper making machine, or adding certain loading material in the paper pulp and then passing them between polished stainless steel rollers at the end of the paper making machine.
Some times the printed sheets are coated with glass like transparent thin layer of varnish to give gloss to the paper.
4. Grain direction: The direction that fibers running in the machine direction in paper is called grain direction. Long grain paper refers to paper in which the fibers run in the same direction as the longest measurement of the paper. Short grain paper refers to paper in which the fibers run in the same direction as the shortest measurement (width) of the paper. Also called machine direction, this factor assumes importance while trimming the paper for multi colour printing process as the expansion or shrinkage of paper is directly related to this.
The paper will get easily torn when torn parallel with the grain. Where the job requires folding the printer will adjust the paper direction accordingly and use the paper. Experts say that the laser printers require long grain paper for the best results since the heat produced in the laser printers causes some curl in the sheets thus resulting feeding problem. Paper folds easier and straighter when folded parallel with the grain direction. grain. Paper will curl easier in the opposite direction of the paper grain. The paper makers usually indicate the grain direction of the paper on the packing sheets. Paper is stronger and less sensitive to changes in relative humidity in the machine direction than in the cross direction of the paper .
5. Gray scale: A photographically produced guide that consists of multiple shades of black and gray beginning with white to black at both ends. This is inserted in the edge of the original while making negatives or positives in a process camera to assess the quality of reproduced negatives/ positives. The processed film negatives/ positives images will be compared with the grey scale to confirm whether the processed film has correct tonal values as per the original. In short the Gray Scale is a quality control device that helps compare tone values of reflection copy with its reproduction. By comparing the processed films with grey scales one can correct exposure and processing conditions to balance the negatives and positives especially in a color reproduction process. Since the Grey scales are not a simple white to black tonal strip which can be prepared by spraying the tonal values on a sheet of white board, they are to be procured from the Photo film firms only as they have been specially prepared in a scientific manner so that the Grey Scale procured from any photographic firms will have the same tonal effect when compared.
6. Grippers: Small metal fingers found on the printing machines which grab and hold the paper as it is printed. This is also a device meant to transport the paper. The grippers may be found on the impression cylinders where the paper is held tight to undergo impression and also are fitted in the delivery chains that take the paper from the impression cylinder and hold them firmly till the sheets are dropped on the delivery board. If the grippers in the impression cylinder fails to hold the paper properly, it can cause mis register of the images. Therefore setting of grippers is as important as any other vital settings on the machine.
7. Gilding : The books kept as achieves or in libraries are normally bound with a full leather or rexin case. In order to quickly see the subject of the book as an eye catcher, to enhance the beauty etc the names, volume, and year of the collection are embossed over the leather case by a process called gilding. Gilding is nothing but Gold decorating the books by a special process. Do not confuse it with Gold embossing or debossing. This is a different technique by which ornamental designs are added on the cover. Some times the entire front cover will be gilded with some design using hand operated gilding machine. The text matter is composed with metal types and mounted in a special frame and given slight heating. The said metal type is pressed against the leather case with a Gold foil paper kept over the place where the text matter is to be imprinted. With the heat, the foil firmly gets adhered on to the leather base. Since the leather cases can not be printed on the printing machines and can be subjected to only screen print which however will not give such a glittering effect to attract the eyes easily, gilding is an oldest technique employed as part of work in binding.
8. Gloss Ink : Ink used and printed on coated stock such as the ink will dry by oxidation cum evaporation without penetration. There are no of glossy inks available in the market.
9. GSM or Grammage : Basic weight of paper expressed in grams per square meter (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 to calculate the weight of a ream of so that the cost can be worked out as the paper is always supplied in weight. The GSM is determined by weighing a known size 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
............Additions to alphabet G to be continued under G/2