The following brief guidelines are intended to assist in preparing digital artwork for submission to AA Labels. They are not intended to be exhaustive or infallible, but following the simple tips laid out below will help to minimise the risk of some common problems which can occur when printing from digital files.

Printing digital images can be frustrating if you don't have an understanding of print quality versus screen quality. A screen quality image, which looks fine on your monitor will often look ragged or pixellated when you print it. This section explains how to ensure you get the best possible print result from your digital images, regardless of what computer program you are using to create your artwork.

Digital images come in two main types: Vector & Raster Images. Vector Images are usually logos or line art graphics which can be enlarged or reduced in size without affecting the quality of the printed result. Most commonly used images, however, including digital photographs (Jpeg being the most common file format), are raster images, which means that they are made up of a finite number of dots or pixels. The quality of this type of image when printed, varies depending on the image and label size.

For example, you might have a picture file which is 500 pixels by 250 pixels in size – and this will not change, no matter how much you enlarge or reduce the size of the picture on the page. So if you make the picture 2 inches wide by 1 inch high, it's resolution will be 250 dots per inch (dpi). As a general "rule of thumb" this is the maximum size you can make this particular picture, without starting to compromise its quality when it is printed.

If you enlarge the picture to 4 inches wide by 2 inches high, its resolution will drop to 125 dpi, because you've got the same number of pixels spread over a greater area. This will impair the output quality when you print it. For the purposes of printed label applications, all your graphics should be a minimum of 200 dpi to print cleanly. For large format printing (e.g. A4, A5 or A3 size labels) 300 dpi is usually preferable, depending on the image. Web graphics and "screen-grabs" are usually only 72 dpi, which is screen quality and looks fine on a monitor, but the results are not as good when printed. Above is a digital image of the Mona Lisa and on the right is an enlargement of the eye. A beautiful raster image made up of millions of tiny coloured squares, becomes pixellated when enlarged.

A table showing examples of minimum raster image sizes for publication and poster quality on standard paper sizes is shown below to provide a scale for use with the label sizes being considered. Most label applications are normally considerably smaller than this, but it is useful as a guideline.

Raster image sizes for label or publication print quality.

Approximate minimum dimensions, in pixels, for raster images to print at Label or publication quality at standard A paper sizes.

Print Size	Dimensions (mm)	Minimum Image Size (Pixels)
A6	105 x 148	1,000 x 1,000
A5	148 x 210	1,500 x 2,000
A4	210 x 279	2,000 x 3,000
A3	279 x 420	3,000 x 4,200

A vector object (stroke or fill) can be given a degree of transparency from completely opaque to completely transparent. On the left is a vector illustration showing fills, strokes and transparency. On the right is an image zoomed into the centre, without any pixellation.

Typical uses of Raster and Vector files.

RASTER	VECTOR
Painting	Illustrations
Photographs	Logos
Textures	Text

Typical file formats:

FILE FORMAT	RASTER	VECTOR	NOTES
			No transparency
			No transparency
			Restricted colour palette. Allows multiple frames (Animation)
			Adobe Illustrator native file format.
			Adobe Photoshop native file format.
			Fonts cannot be embedded.

Microsoft Office is the most common suite of programs used for generating documents for printing, simply because it is available to most PC users. However it is not designed automatically to generate documents which are suitable for printing on press (despite what Publisher devotees might tell you), and most documents need to be manipulated or converted into a suitable format before they can be printed. In most cases, AA Labels will be able to undertake this work for you. It will make our job easier, however, if you note the following points before submitting Office documents for printing:

1. Check Page Setup
This may seem obvious, but make sure your document is set up at a standard UK page size before you begin. This is usually a standard 'A' size like A4 or A3. Depending on your application preferences, Word documents can default to US letter size which can cause problems when the document is printed on A4 label sheets.

PowerPoint's default page size is screen size because it is designed to be used for on-screen presentations, so if you are setting up a document for printing using PowerPoint you will need to also change this to the sheet label page size that you want printed e.g. A4/A3.

2. Use Line/Page Breaks
This is particularly important for long documents, ingredients labels or large informational labels set up in Word which continuously reformats documents automatically, which can cause text to reflow from one section of text to another, particularly if you transport the file between different computers or different versions of Word. This can result in problems like the sections reformatting.

3. Use Standard Fonts
It is always sensible to stick to standard fonts like Arial, Calibri, Bradley Hand, Times New Roman and other popular fonts, as these are installed on virtually every PC – so whichever PC you open your file on, the fonts will always appear the way you are expecting. PCs can only display and print fonts which are installed on their hard drive, so if you use a special or unusual font, and we don't have it installed on our computers, we will advise you of the cost of acquiring that font. Otherwise we will not be able to replicate it correctly. However our studio library of fonts is reasonably comprehensive, but new fonts are regularly being created.

4. Avoid using Web Graphics or Clipart
It is highly advisable to avoid using any graphics, logos or clipart images which you have downloaded from the internet, or photos saved from a web page, unless you are certain that they are sufficiently high-resolution to print cleanly. Screen-grabs or pictures, cut and pasted direct from web pages look fine on screen, but will look very poor when printed and should be avoided wherever possible. This is particularly important if you are increasing the size significantly. The more you enlarge a graphic, the worse it's going to look when it's printed. For more detailed guidance on using digital images, refer back to the previous section Printing Digital Images.

PDF is now the industry standard method for submitting artwork for printing, because it generates smaller (i.e. portable) files and, when used correctly, it ensures that all graphics and fonts are properly embedded so that they will print correctly no matter what computer you print them from. Nowadays many programs have a PDF writer built in, but this is not always the case. Where this is not the case, you will need to have access to software which allows you to create PDF files – from Word, Powerpoint, or whatever program you have used to set up your document. The most well known is Adobe Acrobat. Most PCs have Acrobat Reader installed on them, but this does not allow you to generate PDF files – only read them. The full version of the program is required to generate PDF files, and it isn't free! There are, however, some PDF writing programs available on the web which can be downloaded and installed for free, for example Cute PDF. Most work like a printer driver: instead of printing to your desktop printer or network printer, you select PDF as your destination printer, and then choose your formatting options from the print dialogue box. PDF is a great tool, but it is not failsafe – it will only work properly if used correctly. The following points should be noted when generating PDF files:

Choose the right quality setting. Most PDF writers will give you some kind of choice as to what level of quality you want your PDF to be. This will either be in the form of a description (e.g. "low quality", "standard", "press quality"), or output resolution (e.g. 72 dpi, 300 dpi, 1200 dpi), or both. As a rule of thumb, it is usually best to choose the highest available quality setting, as it's safest to make your PDF better quality than you need. Look for "print quality", "press quality" or "high quality" and 300 dpi resolution or more. "Low quality" or "screen quality" or resolution between 72 dpi and 150 dpi will not usually yield good results and should therefore be avoided.

Always embed your fonts As with Microsoft Office, if our PC doesn't have the fonts you have used in your document installed on it, it will substitute them for something else – which can have unexpected and unwanted results. However, you can choose to embed all the fonts you have used in your PDF when you create it. If you do this, it won't matter whether we have the fonts you have used or not – the PDF will contain enough information to make sure that your fonts print out correctly. Sub-heading and new paragraph. Many programs allow you to export your document as a graphics file, which, like PDF, will allow you to embed all the fonts and graphics in a single file. There are many different graphics file formats, the most common being JPEG (.jpg), TIFF (.tif) and EPS (.eps). However, saving your document in these formats should be approached with caution. A lot of programs (the Microsoft Office suite, for example) will allow you to save your documents as Jpegs or Tiffs very easily, but do not give you much control as to the image quality of the resulting graphics file. In most cases, the resolution of the graphics file will default to 72 dpi – which is low quality, suitable for screen viewing but not for printing. This is a particular issue in PowerPoint and can cause big problems when PowerPoint is used to create artwork, particularly for posters. Another difficulty with turning your documents into graphics files is that the resulting files tend to be massive (in terms of memory) and very difficult to handle – they might be too large to send by email, for example. Because of this we do not recommend that graphics file formats other than PDF are used, except in conjunction with DTP software as appropriate.

DTP (desk-top publishing) software is specifically designed to prepare documents with a view to having them printed on press. They work alongside a family of graphics and imaging programs, e.g. Photoshop and Illustrator . The graphics programs allow you to create and manipulate graphics files, and the DTP software allows you to organise these graphics onto the page along with your text. DTP programs can be tricky to use until you've had a bit of practice, and in order to use them correctly, some basic knowledge of printing processes is required. For the purposes of this document it is assumed that if you are using this kind of program, you will already have this knowledge and be familiar with use of DTP software. However, the following tips will help ensure that the files you submit are print-ready.

1. Use the right colour type
There are several ways in which computers handle colour in picture files, the main two colour modes being RGB (red-green-blue) colour and CMYK (cyan-magenta-yellow-key black) colour. RGB colour is based on properties of light, and is suitable when images are to be viewed on screen, not for printing with ink or toner on paper. CMYK colour is based on properties of ink and should always be used when a colour image is to be printed. The colour mode of your graphics files can be set to CMYK from within your graphics program; the colour mode of your document text can be set from within your DTP program. In addition to RGB and CMYK colour, you may also need to work with Pantone colour, if you are creating a document which is to be printed in just one or two specific colours (e.g. the AA Labels corporate logo colours are Light blue: PANTONE 2995 & Dark blue: PANTONE 3015)

The Pantone Matching System is a universally accepted system which allows you to specify the exact colour ink you want to use, based on a pre-defined colour scale. If you're using Pantone colours, you can't use CMYK graphics alongside them, unless you're intending to print your document in full colour with additional Pantone colours on top – which will increase the cost of your print job. To print only in Pantone colours, you need to make sure that your graphics are suitably set up. The usual way of doing this is to convert them to greyscale (i.e. to discard the colour information and save them as black and white) and then to allocate them the Pantone colour you are using from within your DTP program.

2. Check the image resolution
Image quality is explained in detail in the Printing Digital Images section of this document – but worth a reminder here. For publication print quality any raster images you are using must be a minimum of 250 dpi at the size they are to be printed. An image which is 250 dpi at A6 (postcard) size will effectively drop to 125 dpi if you decide to fill an A4 page with it, so make sure the images you are using are of suitable quality for the size you want to print them.

3. Remember
to allow for bleeds This one is important – and often overlooked. A bleed is where an image or background colour is positioned so that it prints right to the edge of the label. If you're working on a document that has bleeds you need to make the object that bleeds off the label overlap the edge of the label by at least 3mm (see diagram below). The printer prints the document on a larger roll or sheet size than the label size. The extra 3mm bleed allows any movement on the convertor to not necessarily result in a visible white border and/or edge to the labels

The white rectangle denotes the roll or sheet onto which the label is printed. The red line shows the edge of the label (cutter line) NB: This should not appear on the artwork). The blue line shows the area which is printed, allowing for bleeds on all sides (min 2-3mm overlap). The marks at each corner are crop-marks, showing the printer where to cut.

If using label sheets, please always check the label template selected to ensure that it is suitable for printing the artwork produced e.g. sufficient gap between and around labels to facilitate edge bleed if required and not outside of the printable area on sheets (c. 5mm "gutter" around the edge of the page on A4).

In the Above Image:
Example (A) shows the correct use and amount of "bleed". Example (B) shows incorrect use and amount of "bleed".

The range of hues that can be produced by a given colour space is known as its colour gamut. The gamut of RGB varies from that of CMYK. This can cause issues if you submit RGB artwork to a printer. Your RGB file will have to be converted to CMYK prior to printing. If your image includes colours that exist in the RGB colour gamut but not in the CMYK colour gamut then those colours will be shifted by the conversion software to a nearby colour that is. The new colour may not be what you expect… We most commonly see this with customers who have RGB images with very bright vibrant colours. These almost luminous colours look fantastic when viewed on a screen (which is light emitting remember) but are impossible to reproduce in print (which is light absorbing). Set your artwork up in CMYK in advance! If you are working with artwork that is RGB, convert it to CMYK yourself before sending it to us, so you are prepared for how the image will finally look when printed. A comparison of the colour gamut between RGB and CMYK is shown above.