File Types & Digital Terminology
Bitmap – A digital graphic image formed by tiny squares called pixels. The more pixels in an image, the clearer it appears.
GIF – Graphics Interchange Format, a highly compressed file format ideal for simple graphics with limited shading or colour variation. GIF format files of simple images are often smaller than if they were stored in JPEG format, but GIF format doesn’t store photographic images as well as JPEG. GIFs shouldn’t be used for files to be printed on an offset printing press.
JPEG – Joint Photographic Experts Group, a file compression format that allows high quality full colour or grey-scale digital images to be stored in relatively small files.
Pixel – A coloured dot that makes up an image on a computer or television screen.
PDF – Portable Document File, a type of formatting that enables files to be viewed on a variety of computers regardless of the program used to create them. PDF files retain the “look and feel” of the original document.
PPI – Pixels Per Inch, a measurement describing the size of a printed image. The higher the number, the more detailed the image will be.
Raster Image – Electronic representation of printable data using a grid of points called pixels. Each pixel contains a defined value about its colour, size and location in the image – this enables us to print, picture perfect.
RIP – Raster Image Processor, a production device used to convert a digital file into a raster image. The raster image is the electronic representation of printable data.
TIFF – Tagged Image File Format, a bit-mapped file format used for the reproduction of digitally scanned images such as photographs, illustrations and logos.
Vector graphics – These are images created using mathematical statements that define geometric shapes. You can move, resize, and change the colour of vector graphics without losing quality. Unlike bitmaps, vector graphics are not dependent on resolution so you can scale them to any size without losing detail or clarity.
Print Terminology – The Technical Stuff
Blanket – A rubber coated fabric sheet that’s mounted on a cylinder of an offset press. It receives the inked image from the plate and transfers it to the surface to be printed.
Borders – A margin around the edge of artwork. We recommend that all borders are more than 3mm wide on the trim edges.
Coated – Printing papers that have had a surface coating to give a smoother, more even finish with greater opacity.
Corner marks – Marks printed on a sheet to indicate the trim.
CTP – Computer-to-plate, a process of printing directly from a computer onto the plates used by a printing press, it eliminates the need for a separate film-to-plate exposure system.
Digital printing – Printing by a plate-less imaging system. Printed sheets are produced directly from a computer file without being transferred onto printing plates. Perfect for small printing volume, variable data, print on demand & personalised printing.
Dot Gain – The apparent increase in dot size, or tone value, measured on the press sheet compared with the size specified in a digital file or measured on the film separations. The increase is both optical and mechanical and varies with the type of paper and line screen being used. Dot gain is higher with uncoated paper or newsprint.
Dummy – A mock-up made to resemble the final printed product using the planned grade, weight and colour of paper.
Green Printing – Green Printing is printing in a way which is environmentally friendly. This involves the use of more natural inks, recycled papers and energy conservation.
Impressions – Refers to the number of sheets being printed.
Laser printing – A method of printing that uses a laser beam to produce an image on a photosensitive drum.
Lithography – A printing process based on the principle of the natural aversion of water to oil. The printing plate is treated chemically when being made so that the image will accept ink and reject water.
Make ready – All of the work done to set up a job, before beginning a press run.
Offset – A printing method that transfers an image from an inked plate onto a rubber blanket covered cylinder and then onto the printed surface.
Overprinting – The process of printing over an area that’s already printed. Used to emphasise changes or alterations.
Printing plate – The surface that carries an image to be printed.
Quickset – Lithographic inks are designed to obtain a tack-free state as soon as possible after printing to minimise the chance of set-off.
Sheet fed – A printing press that prints single sheets of paper, rather than printing from reels of paper.
Viscosity – The properties of tack and flow in printing inks.
Web printing – A web-printing machine accepts that substrate in a large roll (the web), either in lithographic, flexographic, or gravure processes. These are very fast presses and are the most economic for long run and high volume work.
Wet trap – When varnish or ink is printed over wet ink. The application is said to be a ‘wet trap’.
Binding – This is the process used to keep your books and booklets together. There are many different methods of binding; the most commonly used are saddle stitch, perfect, PUR and burst bound.
Burst binding – Burst binding is similar to perfect binding, however it is more durable. The spine of each section is perforated during the folding process. Glue is then pushed up between the perforations during binding and the cover drawn on. Burst binding is used for books and booklets with multiple pages.
Celloglaze – also known as cellosheen, this is a plastic film heat bonded to printed products such as booklet covers or business cards. It can be either gloss or matt and can be applied to either both or just one side of an item.
Cold lamination (gloss or matt) – Uses pressure sensitive adhesives to bind the film to the material being laminated. This is your best option when you are laminating heat-sensitive work.
Collating – The process of arranging your printed and/or other materials into a desired sequence and packing them for dispatch.
Debossing – An inverted form of embossing. An image or decoration is recessed into the paper, so it’s lower than the paper surface.
Drilling – The process of drilling holes in printed material.
Embossing – A process which produces images or decorations that are raised above the surface of the paper.
Encapsulation – hot reverse and cold front (gloss or matt) – The covering and sealing of your print work.
Finishing – Any process that follows printing, including folding, stitching, binding, laminating.
Folding – When a printed document requires folding for completion, for example A3 folded to A4 or A4 folded to A5.
Gloss cello – A clear, shiny finish that brings out and emphasises colours. It makes images look brighter, adds definition and radiance.
Gluing – a permanent method of fixing multiple items together.
Guillotine – A machine used to trim stacks of paper. The guillotine-cutting blade moves between two upright guides and slices paper evenly as it moves down.
Gumming – Similar to gluing, however it is not permanent. The gum becomes sticky when wet.
Jog – To align sheets of paper into a compact pile before they go to the guillotine for trimming.
Knife, formecut or die cut – The process of cutting paper and card into different shapes after it has been printed. We can create just about any shape you can imagine.
Laminate – A thin transparent plastic coating that is bonded to paper or board by heat and pressure. This provides protection, as well as a matt or gloss finish.
Machine glazed – Uncoated paper with a polished finished on one side only.
Machine varnish – A thin, protective coating applied to a printed sheet to reduce marking or scuffing.
Matt cello – A non-reflective varnish applied to a printed surface to protect it. A matt cello has a slightly granular look and tends to make colours look more vivid.
Mounting – The best way to make your poster stand out is to secure it to another surface. We mount posters on a range of different materials.
Foamcore – A lightweight board made of rigid plastic foam
Corflute – A hollow fluted plastic board manufactured from lightweight extruded polypropylene.
Gatorfoam – A rugged, durable board with an exceptionally hard and smooth surface that resists dents and punctures.
Screenboard – A board with high rigidity and dimensional stability.
Numbering – Printing sequential numbers on your printed material, from event tickets to limited edition series. Numbering can be printed in a number of different fonts and in black or red ink.
Perfect binding – Hornet stacks single sheets of paper together, applies an adhesive to the binding edge and then wraps a cover around the pages. This binding method can be used on booklets and books that are greater than 35 pages.
Perforation – A line of punched holes that allow a sheet of paper to be torn or folded accurately. You might also hear it called a perf.
Saddle stitch – A form of binding commonly used by Hornet to create books and booklets from 8 to 64 pages. The book or booklet is stapled through the middle fold of its sheets using saddle wire.
Scoring – Making a line or a crease in paper or board so that it can be folded cleanly. Scoring is recommended when you require folding on stocks heavier than 150gsm. It minimises cracking of the ink and paper at the edge of the fold.
Spot varnish – Varnish is applied to a particular spot on your printed material – not the whole thing. It creates a shiny effect on just this spot and nowhere else.
Trim – Cutting the printed product down to the correct size.
Trim marks – The guide marks on the printed sheet that indicate where you want to cut/ trim the printed sheet.
Brochure Folds & All About Colour
Concertina fold – A method of folding where each fold opens in the opposite direction to its neighbour, giving a concertina or pleated effect.
Crash fold – Folding a document more than once, subsequent folds fold over previous folds. For example, an A3 sheet folded to A4 and then crash folded to DL for mailing.
Crease – An indent made in paper to make folding easier.
Parallel fold – A method of folding where two folds are parallel to each other. Two parallel folds produce a six-page sheet.
Roll fold – A fold that keeps rolling onto itself.
Z fold – A fold that looks like a Z.
Section – A printed sheet that is folded to make multiple pages. Multiple sections are placed together to make up a book. Individual sections are either saddle-stitched or perfect bound together.
Black – The colour of maximum darkness. For CMYK printing, you will get the deepest black possible by adding 30 – 50% cyan to 100% black. There is no other combination that produces a better black.
Colour mode – Colour mode/space/model must be CMYK (NOT RGB).
Colour separation – The process of separating a continuous tone colour into the four process colours for print production.
Cyan – The blue colour used in four-colour process printing.
CMYK – The abbreviation for cyan, magenta, yellow and black. The colours used in our full-colour printing process.
Densitometre – An electrical instrument used to measure the density of a printed ink colour.
Four-colour process – Printing using four colour separation plates – yellow, magenta, cyan and black. The inks are translucent and can be combined to produce a wide range of colours.
ICC – International Colour Consortium, established by the printing industry to create, promote and encourage the standardisation of colour.
ICC Profiles – Standard guidelines for colour management. The profile allows one piece of software or hardware to “know” how another device created its colours and how they should be interpreted or reproduced.
Key colour – In CMYK, the colour black is the key colour and represented with a K.
Pantone – The name of an ink colour matching system, created by Pantone Inc of USA.
PMS – Pantone Matching System, a standard that creates different ink colours by mixing inks with a minimal amount of base colour. A process guide shows how Pantone spot colours will appear when converted to process colours (CMYK).
Primary colours – The three main colours in the printing world from which all other colours are created, cyan, magenta and yellow.
Proof – Also called Epson Proof, a representation of the colour.
RGB – Red, Green, Blue, a model for describing colours that are produce by emitting light rather than absorbing it. They are known as additive colours because when they are added together they create all colours. RGB colours are what you see on your computer screen, these must be converted to CMYK for printing.
Spot colour – A colour that’s not produced with our standard four-colour process, the colour is printed using ink made exclusively. It’s used when you require a very specific ink colour.
Swatch – A sample of colours or paper stocks.
Woops Houston, we may have a problem!
Creep – When the middle pages of a folded booklet extend slightly beyond the outside pages.
Dust – Small paper particles that accumulate on the blanket of a printing press. These paper particles can cause spots or hickeys on printed material.
Halo effect – When excess ink piles up around the outside edges of printed material. This causes the centre ink to seem lighter.
Hickies – Dust or paper particles sticking to the printing plate or blanket. These appear on the printed sheet as dark spots surrounded by a halo.
Hot spot – A printing problem which is caused by a piece of dirt or an air bubble interfering with plate making, leaving a weak area of ink coverage or significant dot gain.
Scumming – A common printing problem that occurs when the non-image areas of the plate take on some ink. This often causes streaks on printed material
Set off – A printing problem that occurs when wet ink from the printed side of the sheet transfers to the back of the sheet above it.
Slurring – A printing problem caused by paper slipping during the impression stage. It causes smearing of the image.
Strike-through – The term used to describe when ink soaks through a printed sheet and shows up on the back of the sheet.