7. Technical Aspects
7.1 Anatomy of Internet
7.3 Wireless systems
7.4 Client Computers
7.5 Mobile Devices
7.6 Operating Systems
7.7 Computer Programs
7.8 Security: Applications
7.10 Business Intelligence Systems
7.11 Cloud Computing
7.13 DTP Programs
7.14 eBook Readers
7.15 eMail Services
7.16 Expert Systems
7.17 Graphics Programs
7.18 Internet TV
7.19 Music & Video
7.20 Really Simple Syndication
7.21 Rich Media
7.22 Search Engines
7.24 Video Conferencing
7.25 Word Processing
7.26 Cluster Analysis
7.27 Neural Networks
7.28 Pricing Models
7.29 Realtime Systems
7.30 Regression Analysis
There are many graphics programs on the market: the following are the four most popular.
Photoshop is the professional's choice, and well-nigh indispensable for work in a busy art department or photo bureau that outputs to printing presses. The program is expensive, and plugins add further to the cost, not to mention manuals and training courses: the learning curve is steep.
Nonetheless, Photoshop is the industry standard for professional photo editing, graphic design, web design and digital imaging. In its latest incarnation, designers can:
1. Preview, organize, search, and manage image files with the Adobe Bridge File Browser.
2. Employ tools for painting, drawing, retouching, adding notes, and working with type.
3. Edit images nondestructively with layer styles, adjustment layers, masks, smart objects, smart filters, and history.
4. Automate tasks and speed up production with actions, batch processing, history tracking, and scripts.
5. Design for the web, video production, and photography.
6. Use extended version tools for film & TV, medical science, engineering, architecture, and manufacturing fields.
Photoshop CS3 comes with an interface overhaul and new productivity-enhancing features and tools. For Macintosh users, it is the first version to run natively on Intel Macs. Also added are smart filters for nondestructive effects, a cloning palette for transforming and previewing results from clone and healing, and automatic alignment and blending tools. A new quick selection tool matches the simplicity of the magic wand tool, but with much more power, and Bridge, the file browser bundled with all Adobe Creative Suite applications, is improved.
Photoshop Elements is photo-editing software for amateur photographers, digital imaging enthusiasts, and small business users. Built around core elements of Adobe Photoshop, the program excludes some inessential items and adds its own, including a fully-featured photo editor, an integrated photo organizer, project layout templates, artwork and themes, and several sharing options.
Paint Shop Pro
Paintshop Pro offers most of what is needed for web design. Designers can open, edit and save multi-layer PSD files. Each layer acts rather like a sheet of acetate on which objects or brush strokes can be placed independently of the background image. Photomontages are simple as each layer can be positioned, scaled, stretched, skewed and rotated with the new deformation tool. This opens up creative options in allowing changes in a layer's opacity or the way it interacts with underlying pixels.
PSP has a good range of tools, and controls over them, that make the program easier to use than Photoshop for photo retouching. The various retouch brushes have been enhanced with pressure-sensitivity and new options such as "hue up" and "hue down" which move colors through the color wheel and "push" which picks up underlying pixels and paints with them. The smart edge option for the lasso tool allows selections to be automatically made around objects with clear contrast. The line tool can be used in bezier mode to create smooth curves and the crop tool's selection can be resized before being applied. The picture tube appeared in Version 5, and lets the user paint on the image with existing bitmap objects, either of their creation, or in a wide choice of presupplied shapes.
Paintshop Pro is more affordable than Photoshop, and easier to learn. Older versions can be picked up very cheaply, and instruction manuals in secondhand bookshops are cheaper still. Paintshop Pro offers a wealth of features that allow photos to be retouched and/or turned into digital art. Particularly that is the case with later versions, which mimic pencil, chalk and paintbrush.
It's in commercial work that Paintshop fails. Its advanced features are slower to use, particularly the plugins. Its color handling is rudimentary. CMYK separations can be created and sent to the printer with confidence that what results is something approximating to what appears on the monitor or inkjet printer, but it won't be exactly the same, nor consistently the same. PSP lacks a dedicated CMYK working mode with access to the separate cyan, magenta, yellow and black channels directly through its Channels palette and indirectly through its various color correction dialogs.
In PSP the only way to work with the CMYK plates is to use the Split to Channels command to create separate grayscale versions of each channel and then to recombine them. PSP is in fact working in RGB mode, and won't therefore show an out of gamut warning or an ongoing CMYK preview. Indeed, it's not even possible to specify colors by their CMYK percentages.
PSP's control over levels and curves is basic, and its histogram functions only offer the two options of stretch or equalize with no interactive fine-tuning. There is no support for vector-based clipping paths, for example, or adjustment layers, editable text, automatic layer effects, spot color plates, duotones or scriptable actions.
PSP remains a favorite with many professionals for quick and easy work, especially in web graphics, though Macromedia's Fireworks has greatly superior text handling features.
Whereas Photoshop and Paintshop Pro are pixel-editing programs, Illustrator is a drawing program, i.e. is vector based. In drawing a line, therefore, the program does not specify the line of individualpixels should be laid out and given various properties but simply states 'connect point (x1,y1) to point (x2,y2) by a line of certain properties'. The result is resolution-independent, and therefore ideal for logos, illustrations or other designs that may need to be drastically resized. Adobe Illustrator is the best known of several commercial drawing programs, and is commonly used in busy graphics departments alongside Photoshop, with which it shares similar palettes and toolbars. The latest version has many features of Corel Painter, including brush textures, but is less 'painterly', allowing for accurate drawing of graphs and 3D models. Being popular, the product is supported by numerous workshop and third party 'how to' Internet articles. It can import and export practically any type of graphics file, an important requirement in studio enhancement work.
Rather than enhance photographs, Corel Painter is designed to create original works of art and is therefore (with Illustrator and Photoshop) the preferred program of many illustrators. The program centers on the facilities of its brushes, which can mimic a wide range of media (through oil, watercolor, crayon, to pencil, pastel, etc.). The program also includes several of Corel's KPT filters — Gel, Goo, LensFlare, Lightning, ShapeShifter, Reaction and Pyramid Paint.
A tracker palette stores the settings for the last 20 brushes used. Not only can brush behavior be modeled but also that of the medium on which the 'painting' is done: paper absorbency, canvas grain, etc. can all be adjusted. The mixer palette adapts to the real world, since it uses natural colors — Prussian Green, Burnt Sienna, Cadmium Orange, etc. — and allows the user to sample mixtures and parts of mixtures. Brushes can also be used with previous colors still adhering, i.e. not wholly fresh. The new align to path option forces brush strokes to follow the edges of any underlying shape or path. As with any graphics program, work can be undone: strokes, properties of layers, and behavior of the 'paint' medium. The downside is the cost, the long learning curve, and the computer processing power required.
JASC offer plugins for their Paintshop Pro package (Photoshop-compatible too), though these are much more limited than what Painter offers, and create less natural effects.
Painter Essentials is much cheaper and easier to use. The welcome screen provides a painter image on one side and access to recent documents, templates and a selection of training videos on the other. Tools have been simplified: in place of Painter 9's 40 categories of natural media brushes, Painter Essentials offers 18 ranging from acrylic through to tinting. Where Painter offers over 800 brush variants, Essentials pares this down to a more manageable 76. And where Painter offers comprehensive control over every possible brush parameter, Essentials cuts things down to control over size, opacity and grain.
Graphic File Formats
As with any other file, graphics information has to be stored electronically, in some format that records the arrangement of each speck of color in the image. How effectively that is done varies with the graphics file format, some being memory efficient, some good for poster-like spreads of color, some better for photos and some likely to lose information as the file is compressed or exported. The technicalities of file format are for geeks, but page designers do need to know the properties of the main formats, and how to exploit them. It's something of a miracle that file formats can hold such a wealth of information at all, given that a file printing out an image measuring eight by ten inches at 300 dots per inch will need to control the position, hue, tone and transparency of each of these 7.2 million dots. The graphics file formats all use some algorithm to simplify the process, and it's these algorithms that differ between the file formats.
Files have to be read, of course, and that reading or interpretation differs slightly from browser to browser, and also between the Mac, Windows and Unix platforms. Some dozens of graphic file formats exist, but the ones most used are GIF, JPEG, PNG, RAW, EPS and TIFF, plus the proprietary formats employed by the software employed: Photoshop, Paintshop Pro, Painter, etc. All file formats have their pluses and minuses. Graphics programs will convert between different graphic file formats, but designers tend to keep everything in proprietary graphics formats until exported for use elsewhere.
GIF: Graphical Interchange Format
GIF compression uses pattern recognition to compress, and is best used for flat spreads of color as it reduces everything to 256 colors. When used for photographs, however, it will reduce by four times — without losing information: GIF is a lossless format.
GIF has two other advantages: the images can be transparent, and they can support animation. For transparency, one color is designated as the 'chrome key color' and this the browser recognizes by replacing it with the background.
GIF employs two compression techniques on images: CULT (Color Look Up Table) and LZW (named after its originators Lempel, Ziv and Welch). The first indexes (creates a CLUT and references colors to it) and can reduce up to 60%. The second finds patterns in the image and indexes them, creating a lookup table that is not stored with the file but can be recreated at will by the browser. Photoshop's ImageReady facility can compress a GIF file further by losing some of the information: an often acceptable stratagem with large files.
To overcome the 256 color limitation, GIF can dither the image, i.e. create a tiny checkerboard of websafe colors to approximate to the color desired.
JPEG: Joint Photographic Experts Group
JPEG is ideally suited to photographs as it can store up to 16 millions colors, (though black and white may come out better with GIF). Compression ranges from 10:1 to 100:1. At maximum compression, therefore, a 4 MB photo will reduce to a 40KB file, an obvious boon for web displays. The cost is the information lost on compression, and it's therefore usual to keep a backup copy of the original JPEG file, or to save it in a lossless format like TIFF.
JPEG files can be in RGB or CMYK, but are not transparent and do not support animation.
JPEG's compression passes through six stages. 1. Brightness and color are separated. 2. The color space is encoded and reduced by two. 3. The image is divided into 8 by 8 pixel blocks. 4. The components in each block are divided by an individual quantization coefficient. 5. The coefficients are encoded. 6. Compression parameters are saved with the image.
PNG Portable Network Graphic Format
PNG gives the best of both worlds: lossless compression with up to 16 million colors and 256 levels of transparency. PNG also possess a Gamma correction function that ensures images will be equally bright on all platforms (Mac platforms display slighter darker than Windows).
PNG are not displayed by older browsers, however, and the files can be much larger than either GIF or JPEG. PNG does not support animation.
RAW files preserve the settings on a camera for controls like sharpness, saturation or even the ISO setting. These can be read and changed by later versions of Photoshop, giving the photographer the chance, in effect, of retaking the shot through software means alone. Unfortunately, RAW files are enormous, even larger than TIFF.
TIFF Tagged Image File Format
A popular format for storing graphics in a lossless format for printing. Files are large and there are various types of compression: Hoffman, FAX CCITT 3, Packbits, LZW and uncompressed. Color information can be stored either as RGB or CMYK.
Encapsulated PostScript Format
EPS is the primary graphics format for imagery rendered as a Postscript image. The files are large, but can be black and white, or color.
1. Compare the features of Photoshop, Paintshop Pro and Corel Painter.
2. What are the typical areas of use for each of these programs?
3. Exactly what is a graphic file format?
4. What graphic file formats are used in
a. web pages,
b. photo storage, and
c. photographic journals?
Sources and Further Reading
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