More printing terms explained

Question: What is Full-Tone Surface?

Question: What is Digital Imposition?

‍Answer: Digital Imposition is the imposition of digital files direct from computer to film without manual mounting.

Question: What is a Digital Proof?

Answer: A Digital Proof is a proof output direct from the computer without first going to film. There are several different techniques.

Question: What is DPI (Dots Per Inch)?

Answer: DPI is the number of exposure points per inch. A unit that specifies the output resolution for image-setters and printers also known as Printing Dots per Inch.

Question: What is Duotone or Tritone?

Answer: Duotone is an image printed in two colours rather than one (grey scale). Normally black is used together with a further colour. Duotone is used as an alternative to standard grey-scale images as the technique offers a softer more detailed result.Tritone is same as above using black and two further colours resulting in denser and more tonal reproduction.

Question: What is Film Mounting?

Answer: Relates to Films that have been mounted in order to produce printing plates on a foil punched for plate making.

Question: What is Four-Colour Separation?

Answer: Four-Colour Separation is the process of converting a digital image from the additive colour system RGB to the subtractive CMYK system. The conversion is necessary to make the image printable.

Question: What is GCR?

Answer: Grey Component Replacement is a separation method where by the ink quantity in those parts of the image that contain CMYK colours is partly or wholly replaced by black ink. The aim is to limit the overall percentage of ink coverage.

Question: What is Grey Balance?

Answer: Grey balance is when a combination of cyan, magentaand yellow (CMY) produce a neutral grey tone.

Question: What are ICC Profiles?

Answer: ICC stands for International Colour Consortium. Astandardised system for colour processing. Profiles are created to managecolours in the printing process from scanner to paper.

Question: What is Image Definition?

Answer: A low definition image generally lacks clear transitions between dark and light parts. These unclear shade transitions can therefore be enhanced to give better definition.

Question: What is Image Resolution?

Answer: Image resolution refers to how densely the picture elements are packed in a digital pixel-based image. Given in pixels per inch(PPI)

Question: What is Imposition?

Answer: Imposition is the order in which the pages of a printed product are placed so that they appear in the right order after folding.

Question: What is Moire?

Answer: Moire is an unwanted geometric pattern in an image which occurs when the angles between two screen rulings are wrong

Question: What is Monochrome?

Answer: Monochrome is printing in one colour only, usually black.

Question: What is Negative Film?

Answer: Negative film is graphical film on which the non-printing parts are black and the printing parts translucent.

Question: What is PDF?

Answer: PDF or Portable Document Format is a universal file format which retains the typography, formatting, colours and graphics in all types of source document, regardless of the program or platform used to create the document.

Question: What is a Picture Original?

Answer: A Picture Original is the original of an image scanned into the computer, such as a colour slide, a photograph on paper or an illustration.

Question: What is Positive Film?

Answer: Positive Film is a graphical film on which the non-printing parts are translucent and the printing parts are black.

Question: What are PPI?

Answer: PPI or Pixels Per Inch describes the resolution of images, in screens and scanners, for example.

Question: What is a Press Proof?

Answer: A Press Proof is a proof output on a real printing press before the final run is approved. A costly proofing solution and therefore quite rare.

Question: What is a Proof?

Answer: A Proof is a test copy of a printed product, either digital or on film which indicates how the printed result will be. Should simulate printed job as closely as possible. Machine Proofs (proofs produced on printing machine) are the best but the most expensive using press, inks, paper, used in the final printed job. Digital Proofs on coated stock are hard to simulate conditions on printing press using uncoated printing stock.Information would have to be ripped twice, once for the proofs and once for the plate or film. Analogue Proofs using film such as Chromalin are not suitable for uncoated stocks. Most Proofs are digital, using ink jet technology and not printing dots to reproduce images, care has to be taken when evaluating these proofs as they do not simulate moire i.e. screen clash.

Question: What is a Repro Adjustment?

Answer: Repro and films have to be adapted to the paper to ensure that images are well reproduced in print. Typical repro adjustment includes restricting the total ink coverage in shaded areas by adapting under colour removal and choosing the right screening.

Question: What is RGB?

Answer: RIP or Raster Image Processing is hardware or software that analyses and divides text, graphics and images into raster dots before being output on an image-setter or printer.

Question: What is RIP?

Answer: RIP or Raster Image Processing is hardware or software that analyses and divides text, graphics and images into raster dots before being output on an image-setter or printer.

Question: What is Screen/Screening?

‍Answer: Relates to a conventional screen which consists of small dots laid out in a line and grid network. The size of the screen dots can be varied to simulate different shades.

Question: What are Screen Angles?

Answer: Relates to the angle of screened images in true print or printer output. When printing in 4-colour, the screening of the four colours must be in a number or different predetermined angles, otherwise unwanted effects such as moire can occur. Each colour CMYK is output at its own angle i.e. Magenta at 75, Yellow at 90, Cyan at 15 or 105 and Black (K) at 45.This avoids screen clash or moire between the dots output in various percentages from 0% to 100% which would be solid.

Question: What is Screen Ruling?

Answer: Screen Ruling is the density between the dots in as creened image. Measured in lines per inch or lines per cm.

Question: What is Stochastic Screen?

Answer:Stochastic Screen is a screen ruling method in which the distance between the screen dots is varied, rather than their size. The idea is to try to reproduce the structure of a photograph, whereby different shades are created through frequency modulation. Therefore also more correctly called FM screening

Question: What is Trimming?

Answer: In image processing, trimming is the process of removing superfluous parts of an image. This is because the aim is never to work with a larger image than is necessary.

Question: What is Tritone?

Answer: Tritone is a grey-scale image printed with three inks rather than just one, usually black plus two indexed colours. Often used to reproduce more clearly defined details or to soften up a black and white picture.

Question: What is True/Natural Spreads?

Answer: True/Natural Spread is a spread in which the right and left-hand pages are on the same sheet. A false spread is made up of the sides of two separate pages from the imposition. Also known as Imposed Pairs

Question: What is UCR?

Answer: UCR is Under Colour Removal or GCR (Grey ComponentReplacement). In image separation, when a shade is replaced by an equal proportion of black, yet the same colour shade as the original is still achieved. The aim is to limit the overall percentage of ink coverage. The solid areas of a printed image could equate to 400% i.e. 100% solid of each CMYK affecting drying time, set-off, rubbing and low image contrast. On uncoated paper a preferred total ink coverage would be 250% obtained on the plate transferred to the paper. An example of UCR would be replacing a total area of 50% Cyan, 50%Magenta and 50% Yellow with 50% Black. A simple explanation is replacing a four colour dark neutral tonal area with black ink only. To reduce drying time, setoff, rubbing and total ink usage.

Question: What is Viewing Light?

Answer: Viewing Light is the light in which a piece of printed matter is viewed and has a bearing on the overall experience, as shades vary with the light. Light temperature is measured in Kelvin, and a normal light, a viewing light, has a temperature of 5000k, which is normally used as a reference light.

Question: What is Traditional Work-flow?

Answer: Scanning to CMYK for a particular application i.e.size, dot gain, paper used, so scan can only be used for this set of parameters.

Question: What is CMS?

Answer: CMS is Colour Management Systems using ICC profiles which is International Colour Consortium. Allowing for automatic repro and curve applications after scanning for any set of parameters in the ripping process by adding profile curves.

Question: What is RGB/PDF work-flow?

Answer:Scanning work in RGB which is red, green and blue format then creating a PDF which is Portable Document Format which adds profiles to whole document.Advantages are the ability to further publish on the web or use in presentation programmes i.e. Parallel Publication. Also distributing same files to various printers and media databasing for updating and access by selected suppliers.

Question: What is Scanning?

Answer: Scanning is the conversion of coloured originals on a rotary or flat-bed scanner to YMCK or RGB files for subsequent adaptation for printing press, paper used, inks and screen ruling. Colour shades distinguished by the eye are 20 million colours, on a monitor screen there are 15 million colours distinguishable, on coated paper there are 6000 and on uncoated paper there are only 4000 colours distinguishable.

Question: Usage of Digital Camera Pictures

Answer: These are pre-scanned RGB image files and have to have sufficient resolution or enough pixels to achieve good print quality.Resolution is normally twice the screen ruling i.e. 150 line screen needs 300resolution and is governed by size of printed image and screen ruling applied.

Question: What is Image Processing?

Answer: Image Processing is the adjustment to size, resolution, sharpness, contrast, brightness and colour balance to the size required.

Question: What is Optical Illusion associated with Printing?

Answer: Images have to have dots added i.e. a screen for a printing press to add tone reproduction. Screen dots are produced in a RIP (rasterImage Processor) and exposed to photographic film or direct to printing plateCTP (Computer to Plate). They are measured as density of dots per inch i.e. 150dpi. The denser the dot the smaller it is i.e. 200 dpi is smaller than 150 dpi.

Question: What is Tone Reproduction?

Answer: Tone Reproduction is the ability of screen dots output from RIP (Raster Image Processor) in various percentages from 0% to100%, 100% being solid. All colours in an image are reproduced as percentages of Cyan, Magenta, Yellow and Black (CMYK) i.e. Orange would be reproduced as solid Yellow (100%) and 60% Magenta, 0% Cyan and 0% Black.

Question: What is FM Screening?

Answer: Sometimes known as Stochastic Screening which isFrequency Modulated Screening. All dots are the same size but vary in density in a particular area to produce dark or light tonal effects. Measured in micrometres, e.g. 21 - 35 micrometres. Advantages of FM Screening are higher detail due to no dots breaking up the image and no moire from screen clash.

Question: Are your proofs accurate to the final print?

Answer: All the printers used have calibrated their proofing to their own print presses as accurately as digital proofing will allow (visit web site under proofing)

Question: What is Bit Depth?

Answer: Bit depth is a measure of the number of tones or colours in a digital pixel based image. The more bits per colour the greater the bit depth and therefore the higher the number of possible colours.

Question: What is a Blueprint?

Answer: A Blueprint is a form of printing proof in which the result is shown in blue only.

Question: What is a Chromalin?

Answer: A Chromalin is often used rather loosely in the graphics industry to refer to any chemical proof. in actual fact a chromalin isa chemical proof specifically by Dupont

Question: What is CMYK Position?

Answer: An image saved in CMYK actually consists of four separate pixel images in shades of grey: cyan magenta yellow and black. A CMYK image therefore uses four times as much space as a grey-scale image of the same size.

Printing Terms Explained