Advertising Jargon explained

Advertisement Sizes

The size of a display ad is usually described by its vertical height in centimetres and its width in columns. If an ad is 10cm high and spans two columns it is called "ten by two" and written 10x2. Note that the while the height is fixed at 10cm, the width depends on the column width, which varies depending on the publication. Most newspapers and magazines have a column width of around 3cm.

Working out prices

The price will often be quoted "per single column centimetre" or "pscc" or "scc" or "col cm" or just "/cm". To work out a price for the example 10x2 ad above: this ad is 10cm over 2 columns which is a total of 20 column centimetres. If the price quoted was £100 per column centimetre the price for the 10x2 ad would be 20 x £100 = £2,000+VAT.

It is worth remembering that newspaper rates are almost always quoted ex-vat: i.e. the VAT is not included and has to be added to the quoted price.

Document File Types

PDF (Portable Document Format)

The industry-standard device-independent file format based on the Post-Script printer definition language. The idea is that the result is the same regardless of the equipment used to view or print the file. This makes it an ideal format for sending advertisements to publications. The PDF format was invented by Adobe. Adobe Acrobat Distiller software is required to create PDF files. Some other companies have now produced software which can create PDFs although the results can sometimes be unreliable. If you are creating artwork for publication in PDF format you need to make sure you set the software to "embed all fonts".

PSD (Photoshop Document)

The file type used by Adobe Photoshop. Photoshop is suitable for creating the graphics within advertisements but the graphics should then be transferred into a vector software package such as Adobe Illustrator or Corel Draw where the text and borders are added. This is because the vector package maintains the text as lines, which means it will retain its sharpness when printed, whereas Photoshop would rasterise the text (convert to dots) and probably look fuzzy when printed.

CDR (Corel Draw Document)

The file type used by Corel Draw. This is a vector software package suitable for creating press advertisements. In fact we have used nothing else since 1992, when it was the market-leading choice.

AI (Adobe Illustrator)

The file type used by Adobe Illustrator. Illustrator gained ground over Corel Draw in the past few years and is now the market leading vector software package. However, I still prefer Corel Draw!

Image File Types

TIFF/TIF (Tagged Image File Format)

A type of image file which supports very high colour depths and compression types with zero loss of detail. TIF files tend to be very large and are suitable for all image types, where high quality is more important than file size.

JPEG/JPG (Joint Picture Experts Group)

A type of image file which supports very high colour depths and uses various levels of fractal compression algorithms and can produce extremely small file sizes. However this method of compression is "lossy", i.e. image detail is permanently lost during the compression process. Ideal for images with lots of colours such as photos. Widely used for web graphics where small file size (and therefore download speed) is more important than image quality. However, a high degree of image quality can be maintained by increasing the quality setting when creating the JPG file. Consequently the file size will be larger.

GIF (Graphics Interchange Format)

A type of image file which supports a maximum of 256 colours and various compression levels, some of which are lossy. GIF images can also have transparent areas, although partial transparency is not supported. GIF is ideal for small images with few different colours such as logos and web graphics.

PNG (Portable Network Graphic)

A type of image file which was designed to overcome shortcomings of the GIF format, i.e. 24 or 32-bit RGB colour palette and (with 32-bit), 8-bit transparency too. The data compression is lossless and PNG is ideal for internet graphics, however since CMYK colour is not supported, PNG is not suitable for professional-quality printing.

Image Colour Models

RGB (Red, Green, Blue)

A colour model based on the light-emitting qualities of computer screens. On a computer (or TV) screen, the three primary colours of light are used to produce the full spectrum of colours. White is produced when all colours are at 100% brightness and black is produced when all colours are off.

In a RGB image file, each pixel's colour is described as a percentage of the levels of red, green and blue.

CMYK (Cyan, Magenta, Yellow, Key (Black))

A colour model based on the light-reflecting qualities of coloured inks on white paper, as used in the colour printing process as used by magazines and newspapers. A wide spectrum can be reproduced by mixing the three primary colours: red, yellow and blue. However for mixing inks, it is better to use the secondary colours: cyan, magenta and yellow because a wider colour range is available. In principle, black areas could be created with a full saturation of all three colours but in practice black ink is used as a fourth colour for a better, darker black, and to ensure that black text is sharp and readable. The term "4-colour" printing also known as 'Process' printing.

In a CMYK image file, each pixel's colour is described as a percentage of the amounts of cyan, magenta, yellow and black inks which will be required to reproduce it on white paper.

The K stands for 'Key' or 'Black' to avoid possible confusion with the B for 'Blue' in RGB.

Gamut

The range of colours which can be displayed with any particular colour model. A colour which cannot be reproduced is known as 'out of gamut'. Usually the nearest available colour will be substituted. This explains why photographs of sunsets never look as good as the real thing: sunsets emit light whereas photographic paper does not!

Many bright colours which look wonderful on a computer screen are impossible to reproduce in print, because the screen is a light-emitting device whereas paper is a reflective medium. Extreme examples would include fluorescent colours, as are often used for eye-catching headlines on magazine covers. These are printed using a 5th ink of the required colour to achieve the desired result, in addition to the standard CMYK inks.

The visible colour gamut, which is the range of colours the eye can see, includes many more colours than the RGB (red, green and blue) gamut used to show colour on monitors. The gamuts that can be printed with premixed inks (of the Pantone Matching System, for example) or with process inks (CMYK) are even more limited.

Artists and graphics professionals who design for print have to consider the differences between visible, display, and printing gamuts so that they design with colours that can be reproduced with ink and paper.

Pantone

Pantone Inc is a developer and marketer of products for the 'accurate communication of colour in a variety of industries', including graphic design, electronic prepress and production, printing, and textiles. Pantone colours have become an industry-standard way of describing particular colours for reference purposes. The first Pantone colour chart appeared in 1963.

Halftone

The process of reproducing a continuous tone image (such as a photo) on a printed page as a matrix of dots. The position of the dots is fixed in this matrix or grid, and the light and dark parts of the image are determined by varying the size of the dots. The distance between the dots is called the dot pitch or line frequency (see LPI).

Colour depth

The maximum number of individual colours that may coexist within a digital image. In real life the figure is infinite but in the digital world this is clearly not possible so figures must be decided upon which give adequate colour depth for the chosen format.

Resolution

DPI (dots per inch)

The resolution of text or graphics is often measured in dots per inch. A higher figure usually means better quality although too high a resolution leads to unnecessarily large file size. If supplying artwork, 600dpi is an optimum figure.

LPI (lines per inch OR line frequency OR dot pitch)

This figure is fixed by the publication and is the distance between the dots which make up a halftoned image (see Halftone). Although a high figure means a smoother-looking image, the number of colour (or greyscale) permutations reduces as the lpi is increased relative to the dpi of the output device (typesetter or printer). This is because colour depth is given by (dpi÷lpi)², so a publication will normally keep the lpi figure set to 1/16th of the dpi of their output device in order to give 256 greyscales (16²) or 16M colours (256³). A typical modern lpi can now be as high as 150 since many typesetting devices can achieve resolutions of 2400dpi (150x16=2400) and this is why photos in newspapers don't look as dotty as they used to!

Please ask if you want something explained in more detail.

Randal Davies