Graphics for the World Wide Web
For some time there has been a need for a comprehensive software package to create image files specifically for web use, but it’s only recently that several commercial vendors have joined the pioneering shareware writers in meeting this market’s needs.
All in One
WebVise Totality from Auto F/X Corporation is one of the best and most comprehensive solutions to the problems of web image creation yet devised. WebVise Totality features a powerful GIF and JPEG compression engine, a Digital Watermarking system, a unique Optimised Dithering engine for GIF creation, a Hybrid Web Safe Colour palette and an easy to use Animator. All the above are installed as plug-ins for Adobe Photoshop and any other imaging program that uses the Photoshop plug-in specs. All bar the Animator, are also combined into an integrated stand-alone suite. There is also a stand alone Watermark reader that’s freely available, for anyone to check for WebVise’s invisible watermark. Having four modules in one, makes it very simple to compare image quality of GIF and JPEG compression routines, before deciding which way to go.
Perhaps the most striking feature of WebVise Totality is it’s sophisticated segmentation of JPEG compression into various components, each of which can be addressed separately with a slider, and the effect viewed as it’s done. This sort of dynamic viewing is essential for determining exactly how much compression can be applied without unacceptable image degradation. What appeals to me most, is WebVise’s analysis of each image which automatically sets each compression parameter to the optimum level. The settings are so spot-on that I only over ride them on the rare occasion when small file size must take precedence over image quality. If you need to create JPEG or GIF files quickly and efficiently, this feature alone is worth the price of the software. Both Progressive JPEG and the normal JPEG file types are offered. On download, a normal JPEG will grow a line at a time till it’s complete, while Progressive JPEG produces a full image which is fuzzy at first, but gradually gathers more and more detail as it is downloads.
All effects selected are viewed and saved without changes to the original file.
A 1995 change in JPEG specifications, allowed for image areas to be omitted from the ravages of high compression process for enhanced image quality at the expense of file size. Shielded areas of the image are selected by colour using one of various colour pickers. Comprehensive as this is, it would be nice however to have the choice of selecting colours from the actual image.
The smaller the file, the quicker it can be transferred over the Internet. With both the JPEG and GIF modules, transfer speed can be predicted by setting a modem speed in the Download Stats area and then applying different amounts of compression.
GIF made simple
Graphic Interchange Format uses at most only 256 tones or colours but photographic images have many more tones and colours than this. Therefore some degradation of image information will always take place, so this format is best suited to pictures which already have a limited range of colours such as logos, cartoons and line art. WebVise goes a few steps further than most GIF creation programs by allowing control over how this tonal constriction takes place. Red, Green and Blue levels control are used to fine tune results by varying the colour before conversion into an 8 bit palette is made. Using WebVise, you can make a GIF that’s as faithful as possible while still adhering to the 216 browser safe colour scheme. Moreover, there are actually three choices for palettes in WebVise.
Apart from the standard the recommended safe 216 palette, there is a Web Adaptive Palette which is built on a core 216 browser safe palette with an additional 40 adaptive colours derived from the image. Taking this a step further, the third choice is an adaptive palette of 256 colours built not on browser safe colours but on the best colours within the image it’s self. These two alternative palettes will usually render a better result on 24 bit systems.
Optimized Dithering Engine
The Optimized Dithering Engine (ODE) is a separate module for smoothing the conversion from 24 bit RGB colour to the limited GIF indexed palette by selecting important colours and “optimizing” them for conversion. A targeting tool is used to select the desired colour you want to affect, and the Color Variations tab will show 36 variations, all in web safe colours. More variations can be produced by the Brightness Slider.
Dithering refers to the method used in a 256 colour palette to simulate more colours by adjusting the colour of adjacent pixels, thus making tonal transitions appear more natural.
The dynamic range of colours in an image is improved by dithering. The trade-off is file size which increases somewhat along with an increase in dithering. The beauty of WebVise’s “suck it and see” approach, is that all effects are there to see along with the change in file size.
There is a targeting tool for selecting particular colours for particular RGB or Dither control.
The GIF file format supports transparency data which enables you to mask parts of your image and seamlessly layer it over a variety of backgrounds on a web page.
Nine separate local and global transparency options are available, and there is also a Fringe slider to compensate for antialiased areas around the image colour that you have selected for transparency. Additional transparent colour is added by clicking on another colour with one of the eyedropper tools.
WebVise’s watermarking is part and parcel of it’s file creation process. If no watermark is desired, the fields are simply left blank. There is also an interesting option to protect the watermark’s access with a password, effectively making it’s existence a secret. A comprehensive variety of information such as name, date etc., can be included with two levels of security offered. The low level approach simply adds a packet of data to the file’s header. This is also simple to defeat, but most people would not think to look for it and it’s also true that a lot of viewers/users would not want to destroy the added information, so the low level approach is quite useful. Because the information is in the header and not the actual image data, it should also make no difference whatsoever to the image quality. The second approach is to incorporate the information into the image itself as a particular pattern of noise, which in our tests were not perceptible to the eye. This high level form of encryption, known as Interlacing Security Methods, is the most secure form of encoding your copyright information, producing a robust and invisible watermark which is impossible to detect without the program or the freely available ViseMark Reader.
The encrypted information is not removed by re-saving it, cropping it, or by altering it with filters in a minor way.
You may have noticed a red or green dot in the GIF and JPEG interfaces. This tells you if your currently chosen level of compression disrupts the watermark. No more guessing.
The Animator plug-in which appears under the File > Export > WebVise Totality menu item in Photoshop 5, and somewhere similar in other programs, takes the uppermost image on the desktop to build an animation with it. To add to the animation you simply bring another image to the fore of the desktop and hit F4 or re-select WebVise Animator from the menu. This arrangement is simple and effective but an option to use Photoshop Layers would be desirable. Perhaps in some future version.
Animator supports frame delays, overlaying, and also most of the features in the other modules such as download statistics, transparency regions.
In the stand alone application all the modules and their functions can be brought to work on a whole folder of files by using the Batch Process mode.
The Auto/Feed command will feed the files, one after another for manual processing and adjustments while Auto/Process will do the lot with predetermined parameters.
Unfortunately in the version for the Apple Macintosh platform which we tested, the Batch Process module is poorly designed and only partially functional. We found several other bugs in the program and were disappointed that Auto F/x has not closely followed standard Macintosh interface specifications. These failures degrade what would otherwise be an outstanding application. We believe though, that WebVise Totality’s unique combination of useful features makes these small annoyances worth tolerating.
HTML image maps
Both the JPEG and GIF interfaces feature Integrated Image Mapping for easy creation of web page links. Integrated Image Mapping creates client side HTML image maps that can be easily slipped into web pages in most web authoring programs. Drawing tools are used to select an image map area and when the GIF Or JPEG is saved out, WebVise will then prompt you to save out the .html page that contains the image map tags and data.
I like a good manual and WebVise comes with an excellent one in both written form and PDF, for online viewing. It’s easy to read, well laid out and covers all the bases.
Windows 95/NT 3.0.1 or higher
System RAM: Minimum of 16 MB /32 recommended
Storage Space: 10 MB or more
Apple Power Macintosh:
System Software: 7.1 or higher
Storage Space: 10 MB or more
System RAM: Minimum of 24 MB / 32 recommended