OptimizingGraphics for the Internet

Introduction
Scanning Graphics

Resolution
Number of Colors
File Formats

GIF
JPEG

Scanning Text

Optical Character Recognition
For digital display

Mustek Scanners

Handheld
Sheetfed
Flatbed

Conclusion

1. Introduction

Making a home page on the Internet can be fun and exciting (sometimeseven profitable). To make the best home page, you will need to have thebest tools. A scanner is an important part of making a distinctive andrecognizable home page and Mustek is one of the most affordable scannersaround. Before you go out and buy a $1000 scanner, look at what exactlyyou will need in terms of resolution and color depth.

2. Scanning Graphics

Here are a few guidelines to help scan better pictures. Some ideas ofthings to scans are pictures of people, real buttons for web pages, andcorporate logos.

Resolution

Unlike money, hard drive space and processor speed, with resolution,less is more. Graphics on the Internet take forever to load. That’s becausepeople often scan at resolutions and color depths much bigger than theyneed.

Most scanning software tells you what your scan is going to be in inchesand dots-per-inch. A typical scan might be 5" x 5" at 600 dpi,which would create an image 3000 x 3000 dots. Standard VGA supports a 640x 480 resolution, better video cards 800 x 600 and 1024 x 768 resolutions.A picture of 3000 x 3000 wouldn’t fit and would take 70 times longer toload than the same image at 72 dpi! Web publishers don’t think in termsof inches and dpi, they think in terms of pixels. All Mustek scanners allowchanging the units from inches to pixels.

To fill approximately half of a standard VGA display, the graphic wouldneed to be around 320 pixels wide. Lower the resolution until the pictureis approximately 320 pixels wide. On a 5" picture that would be around60 dpi. If the resolution doesn’t go low enough to scan an image 320 pixelswide, scan a 640 pixel wide picture and use the software to scale the image.

Number of Colors

The rule of thumb when displaying pictures on the Internet is the lessinformation you can give and still have it look good, the better off youare. Lets say you scanned your company logo which has four colors, green,gray, black and white. You could easily save this as a 16 color file. Ifyou were to save this as a 24-bit color file, it could be as many as 6times bigger, display no better while still taking much longer to load.

When scanning pictures of landscapes, people, and even product shots,the number of colors is important. 256 colors won’t display these typesof images very well, for optimal display, 24-bit color is needed. Doesa 30-bit scanner help? Yes, 30-bit scanners help get the best possible24-bits (assuming your picture is either too dark or too bright).

File Formats

There are two different file formats popular on the Internet, both arevery different. The question isn’t, "Which file format is better?"That question is much like, "Which is better a hammer or a screw driver?"It isn’t so much which is better, its which tool should I use for whichjob. Use the hammer to drive nails, the screw driver to remove the screws.Warning: using a hammer to remove the screws from your computer could voidyour warranty. ;^)

GIF File Format

The GIF file format is a lossless file compression format. Informationon areas with similar colors are compressed. For example most of our companylogo is white and could be compressed in the GIF format, where a pictureof a person has subtle tones which could not be compressed.

Some GIF file formats support a handy feature called interlacing. Interlacingsaves the file with the odd line information first, then the even lineinformation. This allows the user to get a good idea what is coming up,so they don’t have to wait until the entire button is shown before movingon. These graphics don’t really load any faster, they justseem to.

Another handy feature of GIF is the ability to save transparency information.Round buttons would have background areas that you would have to specifyfor each different background; however, with GIF and transparency, thebrowser can automatically overly it on any color or textured background.

The software shipping with Mustek scanners do not support these twofeatures, in fact even very expensive software like Adobe Photoshop doesn’tdirectly support it. However, your scanner works with other image-editingsoftware which does. Some of which are even available for free on the Internet.

GIF files are usually 256 and 16 color files called "Palette Color."So you wouldn’t want to save images that had many more colors. The GIFfile format is most often used when saving buttons and other small items,because they have very few colors and lossy compression would make smalltext unreadable.

JPEG File Format

The JPEG file format is a Lossy image compression format. It was designedby a group of very smart people to compress pictures of natural objects.It does some fancy mathematics to allow images such as people and flowersto be compressed from sizes like 1 megabyte to sizes like 50K. When compressingan image that much, some information is lost. Pictures of people and flowersaren’t changed much with JPEG; however, items like company logos oftenlook fuzzy and distorted.

JPEG has a cool option called Progressive rendering. Its much like GIFInterlacing but its much fancier and looks more interesting when its loading.Very few programs support progressive JPEG (for example Adobe Photoshop3.0.5 doesn’t support this feature), but if you have one that does, itis a great addition to any Internet toolbox. Some handy utilities existon the Internet for converting images into Progressive JPEG.

Because JPEG saves files with 24-bit color information, use this fileformat for picture of organic items like people and landscapes and useGIF for things like buttons and logos.

3. Scanning Text

Converting old brochures and memos from the paper world to the digitalworld is made much easier with Optical Character Recognition (OCR) software.

Optical Character Recognition

When converting from paper to HTML, you don’t want to use programs whichoffer format retention. For best results, it is best to scan the text andlay it directly into an HTML editor. The formatting used by most documentsis hard to undo in most word processors and isn’t support by the HTML standard(i.e. multiple columns and snaking text).

The OCR software that ships with Mustek scanners offers an excellentrecognition rate and doesn’t retain non HTML formats like multi-columnand snaking text.

For digital display

When scanning text for display, do not scan at high resolution. Thelower the resolution the more text you can fit on a page. Text is veryreadable at 72 dpi when scanned in grayscale. Don’t scan entire documentsand just put them directly onto your web page. A single 300 dpi line artpage takes one megabyte which can take 10 minutes to display on some Internetconnections.

4. Mustek Scanners

Mustek offers a wide variety of affordable scanners which will makea valuable addition to any web publishers toolbox.

Handheld

Handheld scanners are small, compact, inexpensive devices for scanningcasual pictures smaller than 4.13". They are good introductory scanners.They aren’t very useful for OCR but they are useful for capturing picturesand logos.

Sheetfed

Sheetfed scanners are small, fax like scanners for scanning multiplepages. They are affordable and Mustek sheetfed scanners offer 10 page AutomaticDocument Feeders (ADF). Best used for OCR and scanning pictures. They aren’tgood for scanning 3-dimensional material like buttons, jelly beans andwatches.

Flatbed

Flatbed scanners are photocopier-like devices which allow you to scanpictures, text and small 3-d objects. They are the most convenient andflexible scanner type. They cost slightly more than the other types, butare well worth the added expense for the serious web page developer.

5. Conclusion

Mustek scanners are a valuable tool for scanning pictures and graphicsfor the Internet. With the addition of some low cost third party software,users can be producing professional quality web pages at a fraction ofthe cost of having them produced.