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Multimedia In Web Design Part 2
Images and icons are very useful for adding interest to a page, both from the flash point of view (which can be very important for some audiences) and from the information point of view. Images can be very important in many presentations, and the Mosaic browser's original use of images and other multimedia fueled great interest in the Web. Images can have a strong visual impact on a Web site as long as they are not overdone (multimedia overkill) or poorly arranged (clown pants). Images also are required when using imagemaps. Images play a large role in the Web, and placing images in Web pages and having the capability to manipulate them with "tricks" can help a developer make the best use of them. Image Placement and Size You can use many tricks to manipulate the placement of text with respect to images. Using the Align attribute of the IMG element, you can set the alignment of text with respect to an image. Transparency, Interlacing, and Animation Another extremely useful tool is for making GIF images transparent and/or interlaced (or progressive). A transparent GIF image is one in which a selected color is "taken" out of the graphics file when displayed, so that the browser background shows through the image. Minimizing Image Size Because every image on your web must be transferred to your users through your server, you'll want to minimize your image size. Both you and your users are paying for the transfer-not necessarily just in terms of connect time, but more important, in terms of personal time. If your users find that your pages are chock full of images, they might not come back. But images on the Web are a bit like potato chips; they are fattening, but users like them nonetheless and probably would miss them if they were gone. You can use some techniques to minimize the time it takes to transfer the image files you have in your web: 1. Reduce the amount of graphics on your web pages to the minimum necessary to support your goals. Then maybe shave off some more graphics beyond that. Every image on your site should do one of the following: - Carry important information content, - Provide aesthetic enhancements that add to the value of the information for the target audience. The amount of graphics on a web page does vary by the audience and purpose of your document. Don't let anyone tell you to never use graphics or to always use graphics. The bottom line is this: Think of what your audience wants. 2. Reuse graphics that are at your site. When your users have their browser caching enabled, they can download an image once and their browser displays that image wherever it is referenced. If you have a logo or repeated graphic, reference the same graphics file on every web page where it occurs. You therefore can get more use out of the graphic with no additional cost in time to your user. 3. Choose the best image format. If you are using a photograph, continuous-tone art, or graphics with lighting, JPEG is the format to use. If you have a line drawing, flat art, or a cartoon, the GIF format is a good choice. 4. Lower your standards for quality. For your JPEG images, using an image tool, you can choose the degree of lossiness when storing the JPEG image. There will be some degradation of image quality, but your payoff is in a faster image display to the user. 5. Give the browser some hints. Use the Height and Width attributes of the IMG element for every image on your web. This helps browsers lay out the page and put down some text for the user to read while the images download. This doesn't speed up the downloading of the images, but it does reduce the time between the user requesting your web page and getting something useful to see. 6. Get progressive or interlaced. You can use tools for making your JPEG or GIF image appear on-screen in stages so that a user sees your image in stages while it comes into focus. Look for interlaced GIF tools or progressive JPEG tools to do this. Image, Background, and Text Color With Wilbur, you can control the color of a web page's background, text, link, visited link, and active link. You can control the size and color of every character of the web page if you want. Developers wanting to show off that they know how to change these colors do so, resulting in the most gaudy, unreadable hodgepodge of color. Graphics designers no doubt cringe when they see such results on the Web. The color situation on the Web is even worse when you realize that colors can look different on the various systems your users have. If you have designed your images and colors to be very attractive on a UNIX workstation, those same colors can look bad (or even unreadable) on a Macintosh or PC system. Users have a wide variety of monitor types (including monochrome!), color cards, and screen-resolution levels. To choose colors well, you need to pay attention to contrast and value, instead of just how the color looks on your monitor. If you choose colors with the right mixture of contrast and value, your result will tend to work well on a variety of monitors. You won't achieve the same results on every platform and monitor (that is impossible), but at least you will serve your users' needs better. The best way to check the contrast and value of your Web page colors is to convert them to grayscale and examine the results. Here's one procedure to do this: Bring up your web page on your monitor. Use an image grabbing tool to capture an image of your whole web page or a section of it. Manipulate this image in a graphics tool and set it to grayscale. Observe the results. Is every word and contour of the images visible? Can you read what you see? You can make an adjustment to your web page, reload it, and repeat these steps until your image, when translated to grayscale, is readable. If possible, try this same experiment on a Macintosh, PC-Windows, and UNIX platform. If everything still is readable in both color and grayscale on all these platforms, you're not guaranteed a good color, but at least you've examined your color scheme for contrast and value. More about web design on http://kate-web-design.co.uk Article Directory: http://www.articledashboard.com |
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