10 THINGS YOU NEED TO KNOW ABOUT PRINT

1 Printing MethodsUses etched printing plates (usually aluminium). The printed image is offset onto a rubber roller. This makes the plate last much longer than if it were to come directly in contact with the paper, and the rubber can press the paper with much more pressure- creating a sharp image.

Litho is a very fast process, producing up to 11,000 impressions (individual printed sheets) per hour and is suitable for medium volume jobs. It it not suitable for high volume jobs as the plates wear quickly and would need to be replaced.

Web offset is another version of litho that uses large rolls of paper instead of individual sheets. This is a much faster process and it more suited to higher run print jobs- such as brochures and publications with lots of pages.

This is a more expensive print method that is best for very high volume jobs, such as the printing of magazines and newspapers and money. It uses thick etched copper or resin plates and much thinner ink than litho that fills the grooves in the plates rather than sticking to a raised surface.

This method produces the highest quality prints available of images, but the quality of text suffers. This is due to the consistency of the ink, the thinner ink spreads as it hits the surface of the page- creating continuous tone in image.

Uses durable inks, its a method used on tshits fabrics and metals. Rotary screen printing machines can be used to print of cylinders.

Used for printing onto 3D items, memory sticks, pens etc.

Offset Lithography (Litho) Rotogravure (Gravure)

Screenprint

Pad Printing

Flexography (Flexo)

Digital printing

This uses a similar method to litho but the plates are made of rubber not metal, so transfer the image straight to the printing surface. The ink used is very sticky so can be printed onto a large variety of surfaces including non-porous ones like plastic and metal. Because of this the quality of flexo printing is quite low and is often used for food packaging. When used for short runs flexo machines can print directly onto packaging blanks such as carrier bags rather than onto a roll of stock.

Good for short runs but can only produce CMYK prints, spot colours can’t be printed. The image gets transferred directly from digital file to paper so it is the cheapest method for short runs – no expense is needed to make printing plates. The price per unit however is quite high. Comparing the run size to the cost of setting up litho would determine the best method to use.

Diagram of how the Offset Litho process works

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2 Colour ModesStands for Red Green and Blue, the additive colour mode for screen. It has a much larger colour gamut than CMYK, and not all RGB colours can be reproduced in print. For this reason it should never be used as the colour mode for print files. exception. When producing images in photoshop its best to work in RGB mode, as not all photoshop filters and effects can be used in CMYK. Once the image is finalised it should then be converted to CMYK before being sent to print.

Stands for Cyan, Magenta, Yellow and Black, the 4 colours used in the subtractive colour mode for print. When mixed in different proportions, these 4 inks can reproduce most colours in the print gamut- but particularly bright or vibrant colours can be hard to reproduce.

Cyan, Magenta and Yellow and their subtractive secondary colours.

Some printers can produce 6 colour separations, using an Orange and Green ink in addition to the CMYK to produce a greater range of colours. The orange and green take the place and screen angle of either Cyan or Magenta during the printing process to prevent moiré patterning occurring. Pantone claims that up to 90% of its spot colours can be reproduced using this 6 colour process. This is an advantage for both printers and designers, as the printers can produce this wide range of colours without having to set up the machine with a new spot colour for each print job, and designers can produce print work that has a much larger colour spectrum - closer to that available in RGB

RGB

CMYK

Hexachrome

3 Spot Colours

Example of a pantone colour book in the adobe software. Once a colour has been decided on using a physical Pantone swatch book, its colour information can be embedded perfectly in a digital file using these swatches. Colours should be chosen using the physical pantone book, and not this chart as the differences between screen and print mean the colours will not print exactly the colour the look on the on screen swatch.

These are special colours that are mixed prior to being printed. They are usually used when CMYK can’t reproduce a desired colour, or when a colour has to be reproduced consistently across a range of branding such as a company’s logo colour.

The most common source of spot colours in this country and globally is the Pantone Matching System (PMS). This is a globally recognised standard set of colours that can be specified. Each of these spot colours is mixed specifically to a standard recipe so can be reproduced accurately at any commercial printers.

There are a few advantages of using Spot colours over the standard CMYK system. Firstly there is the cost. If you have created a design that uses less than 4 colours, printing a colour using the Pantone spot colour, rather than the CMYK equivalent means less printing plates are needed. As the production of these plates is one of the more costly elements of a print job a lot of money can be savedSecond, a pantone spot colour is a solid colour, and if printed as a 100% tint will completely coat an area of a page. This is useful as if a light colour is needed, it can be

reproduced as a solid block rather than with halftone dots.Third is the consistent reproduction of colour. Using CMYK means there is always the risk that 2 separate jobs will produce tones that are slightly different. Because spot colours are pre-mixed, they can be reproduced consistently at any printers.

4 Special FinishesCoats a page in a protective varnish. It can be applied to a whole page or just to key parts to enhance a design. Spot varnishes can be applied in different finishes such as glossy, matt and silk. UV varnish is often used to highlight particular images as it provides a higher gloss than normal varnish.

A design can be pressed into the surface of a stock to produce a raised or indented image. It gives a subtle design element but usable designs can be limited depending on stock choice. Thicker stocks wont show fine details well. Can be applied to printed areas or plain papers(blind embossing)

Process of applying powder to a wet ink that when heated, melts to form areas of high gloss.

These are special coloured foils that are attached to stock using a heat press. They are available in a range of colours, including metallic colours that have a high shine.

this process adds interest to a design by cutting the stock into unusual shapes specified by the designer. It cuts the design using a steel die.

Spot Varnish Embossing

Thermography

Foils

Die Cutting

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Overprinting5A process allowing process inks to print over each other, creating mixed tones. Colours are overprinted in the order of the printing press (usually CMYK or the order spot colours are printed) overprinting can be used to produce deeper blacks as well as for creating interesting visuals.

Setting up overprinting options correctly is crucial, as it can change the entire look of a job.

If specifying things likes spot varnishes, and foils with a spot colour - need to make sure this layer is set to overprint or it will knockout the print underneath, making registration of the 2 layers extremely hard. This could also ruin the effect of a special finish - as if a spot varnish channel knocks out the print underneath, it will be printed onto plain paper rather than enhancing the print that was meant to be underneath. This could be a design feature - but needs to be checked before sending to print.

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6 Paper SizesSRA sizes are slightly larger than A sizes to allow for crop and bleed, C sizes are used for envelopes

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ISO paper sizes are the recognised standard in most countries. They work using a standard aspect ratio for the length and width of pages

1:√2This is an effective aspect ratio- as if a sheet using this is folded exactly in half along its longest edge, the folded sheet will always have the same 1:√2 aspect ratio.

7 Paper TypesPaper to which a coating has been applied during the paper making process, usually chalk or china clay. This coating can change various attributes of the paper, but the most noticeable is the texture of the surface. Coated papers tend to be brighter, smoother and have a lower ink absorbency. This is advantageous, as it means printed images are sharper and more vibrant.

This paper is less suited to items that require long lengths of concentration, such as books, as the glare can make them hard to look at.

Paper that has no coating. It has a rougher, more textured surface than coated papers, and absorbs more ink. Its generally cheaper than coated paper.

Coated Paper

Uncoated Paper

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8 BindingEach of the sections of the publication are arranged in order. The folded edges are trimmed and then roughened so that they can hold more glue. The edge is coated in glue and and attached to the cover of the publication.

Constructed in a similar way to thread stitched publications, signatures are separated into 16 or 32 page sections. These are individually stitched, then grouped together and glued to the hard cover.

Common binding type for magazines, booklets and catalogues. Pages are fastened together through the spine using staples. This allows the publication to lie flat whilst being read, making it easier to use by the user.

Perfect Binding Case Binding

Saddle Stiching

The publication sections are individually stitched. The sections are placed in order and clamped together. The stitched edge is then coated in glue and attached to the cover. Similar aesthetic to perfect binding, but this method is stronger and more suited to books - things that need to be more durable.

Thread Stitching

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9 Colour Modes 2Images printed using a single colour and its tints. This technique works well with spot colours as well as grayscale images, and if printed onto coloured stock can produce interesting results. Monotone images can also be combined with a flood print or block shapes of a spot colour to achieve similar results

Monotone (above) and duotone (right).The levels and interaction of the 2 tones can be altered to create greatly differing variations with the same 2 spot colours.

As with duotone but using 3 specified colours.

As with duotone but using 4 specified colours. The most common application of this is the CMYK printing method, although any 4 spot colours could be used.

Monotone

Tritone

Quadtone

Similar to monotone, where 2 spot colours are used. An image is only described as Duotone if the 2 spot colours include tints that interact with one another. if one of the colours is solid then this is monotone with a spot colour.

Duotone

10 Print ChecklistProduce a mock up of the job for the printer. A black and white copy will be sufficient but its important that the size and layout of the mock up is accurate. This will give the printer a point of reference whilst the job is being processed and they will know what the job should look like in the end

If using a special finish, indicate the areas this finish is to be applied on its own colour channel - using a PMS colour not used elsewhere in the design. You MUST explain to your printer what you want the channel to be used for or the spot colour will be printed.When indicating a channel for spot varnishes the layer must be set to overprint, or the shape will knock out the colours underneath and the varnish will be applied to unprinted stock.

Before a job is transferred to the printing plates, the printer will supply you with a final digital proof to check. CHECK IT! Once this has been approved there is no other chance to edit the files, and any mistakes will be reproduced across the whole job, which could be very costly to amend. Always show the final proof to the client for them to sign off, this way if anything is wrong in the end, the blame is with the client and not yourself - as they signed and approved the proof.

Mock up Spot varnish/specials

Sign offEnsure that the final document to be sent to print only contains the swatches of used colours - especially important for indesign doccuments (either the CMYK channels or the specified spot colours) When the printers separate the channels all swatches in the pallet will register their own separation (even if the colour wasn’t used) which you may be charged for.

Colour specification

TIFF - use this for photographic images, anything that is in bitmap or a grayscale image. It is an uncompressed file format, so files will retain as much image information as they were created with, meaning the files will remain high quality and sufficient for print, but the files will be very large.

VECTOR IMAGES - if created in illustrator, leave these in .ai format as this will keep the images editable, if you decide half way through a job to change the colour scheme, or the composition of the whole image, the vecors can be edited simply. .ai files can also be copied and pasted straight into indesign without linking the files. Vectors can also be saved in PDF format, but this makes the image harder to edit if required.

PSD - use this format to preserve layers and transparencies in an image. This is useful if formating photographs with feathered edges or entire transparent areas, as they can be placed over a background image in indesign and merge/overlay visually in the desired way without having to create the entire composition in photoshop. It makes the composition more easily editable.

INDESIGN FILES:these can be sent to the printers in two ways1) Package the file. This collates all the images and fonts used in the file and places them in a folder, ready to be sent to the printer. Before the file is packaged - all files should be checked to ensure they are in CMYK mode, at the required resolution and in appropriate file formats. Check the printer has all the fonts you have used, and that these are listed in the job info, along with the names of all the image files. All the file links also need to be checked before packaging a file, if any are missing or wrong they will not be packaged correctly.

2) Save the job as a PDF. This is a more reliable format in soem ways, as all the files and fonts used within the project are contained within the single file. They are also harder to edit so there is less chance something will get changed acidentally between it being sent and printed. More and more printers requre this format over an indesign or quark express file, as they are easier and quicker to set up for print. this also means its less likely mistakes will be spotted once the file has been sent, so it is essential to run a pre flight check.

File formats