Introduction to Scanning

Part of the Digital Library Workshop

Web Institute for Teachers 1999

Bill Geraci and Sally Levin, Presiding

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What Is a Scanner?

A Scanner is a piece of hardware that sits outside of your computer and is connected to it.

There are different kids of scanners, the most common being "flat bed". This allows you to put a piece of paper (or other object) flat on its bed. You can get good scanners now-a-days for under $100. They look, mostly, like this:

Flatbed scanner

There are also sheet fed scanners. If you have one of these you feed in pieces of paper one at a time. (This means you can't scan something that isn't flat.) These were popular because they were cheaper and they take less desktop space. They look like this:

Sheetfed Scanner

There are also Drum Scanners. These are the most expensive and highest quality scanners. But they're really expensive; they may cost thousands of dollars. They look like this:

Drum Scanner

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What Can You Do with a Scanner?

Scanners make digital (ie: computer) files that are the image of what they scan.

Say you've got a photograph you like and you want that photograph to appear in your web page. You have to get that paper photograph into a form your computer will understand. That is, "digitize" it. When you're done you'll have the photograph still in its paper form and a file on your computer that contains an image of that photograph.

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Connecting One Up

Most scanners are ìSCSIî devices because image files created by scanners are big files.

SCSI sands for Small Computer Standard Interface
SCSI has been built into almost all Macintoshes
You usually add a "SCSI Expansion Card" to a PC so it can connect to SCSI devices
SCSI is great for devices that exchange big files (like scanners and hard disks)
SCSI is now being replaced by another standard called FireWire

Once you have the scanner, connect it up and install its software.

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Installing Software Drivers

After you add a new device to your computer you need to install a hardware driver into your System. The software you install usually comes on a CD.

This is so that the computer can recognize / make use of that device

True for almost all hardware, not just scanners

Always read the packaging and ReadMe file to make sure your driver works for this specific kind of computer and works with the version of the System you have on your computer.

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Installing Software Graphics

One you install a scanner, you need to install graphics application software to make use of the scanned images the scanner creates

This is in addition to the driver

This software does two separate things

Allow you to get images from the scanner at all

The driver just makes it *possible*
You need the software to work with the scanner

You usually also get software that will allow you to manipulate the images you get

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The Steps in Using a Scanner

Set it up

Install all the software

Put something in it

Onto the flat bed or feed it through

Scan it!

This creates the file

Manipulate the scanned image

Make it look as you like
Just print it, montage, merge & meld, alter, etc
Check this link for some applications that edit images: http://cuip.uchicago.edu/wit/99/mentors/Zumpano/graphics.htm#Image Tools

Make use of the scanned image

Put it in a publication, up on a web page, printed out, etc.

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Adjusting Image Quality

Once you have an image you can edit that image.

Brightness and Contrast

How dark / light, grainy / smooth

Color and Hue

Color adjustments

Crop

Get just the part of the image you want

Effects and Filters

More....

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Terminology Pixels / dpi

Pixels is short for PICTure ELement

dpi is short for dOTS pER iNCH

The smallest piece that makes up part of the picture
Computer monitors are usually 72 pixels per inch
Printing can be up to 2400 dpi

The more dots per inch / pixels the smoother the image

And the bigger the file!

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Terminology Resolution

Resolution is how smooth the image is

dpi or Pixels is a measure of Resolution

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Terminology ìColor Depthî

How many ìbitsî of information for each pixel?

1=black and white
4=16 colors or shades of grey
8=256 colors or shades of grey

The standard

16=Thousands of colors
24=Millions of colors

More than 24 bits per pixel carries other info *and* still makes the file bigger!

More color depth means the file gets bigger!

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Terminology Image Size

This is how big the image is

Usually measured in pixels

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File Size / Detail Factors

Here is a description of an image

ì72 dpi, 16 bit, 340 x 230î

This tells you what quality and size file you have

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Problems with Scanning

You may have to start with poor originals

Combersome to work with lots of originals

Imagine scanning War and Piece!

Most scanners are big--they take up desktop space

You can spend lots of time in the software making it look just right

And you may never get it just so!

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Alternatives to Scanning

There are other ways to get images into your computer

Steal it
Clip art collections
Download image files

From the WWW, other sources

Paint / draw it yourself with paint and / or draw software
Kodak Photo CDs
Digital Cameras

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Kodak Photo CDs

Take your camera shots with a file camera

As you send the film in for development

Specify on the Options you want a Kodak Photo CD

More expensive than ìjust picturesî but then you have the images in digital form

And several different resolutions, too

Introduction to Scanning

Part of the Digital Library Workshop

Web Institute for Teachers 1999

Bill Geraci and Sally Levin, Presiding

Contents

Related Links

What Is a Scanner?

What Can You Do with a Scanner?

Connecting One Up

Installing Software Drivers

Installing Software Graphics

The Steps in Using a Scanner

Set it up

Install all the software

Put something in it

Scan it!

Manipulate the scanned image

Make use of the scanned image

Adjusting Image Quality

Brightness and Contrast

Color and Hue

Crop

Effects and Filters

More....

Terminology Pixels / dpi

Pixels is short for PICTure ELement

dpi is short for dOTS pER iNCH

The more dots per inch / pixels the smoother the image

Terminology Resolution

Resolution is how smooth the image is

dpi or Pixels is a measure of Resolution

Terminology ìColor Depthî

How many ìbitsî of information for each pixel?

More color depth means the file gets bigger!

Terminology Image Size

This is how big the image is

File Size / Detail Factors

Here is a description of an image

This tells you what quality and size file you have

Problems with Scanning

You may have to start with poor originals

Combersome to work with lots of originals

Most scanners are big--they take up desktop space

You can spend lots of time in the software making it look just right

Alternatives to Scanning

There are other ways to get images into your computer

Kodak Photo CDs

Take your camera shots with a file camera

As you send the film in for development

More expensive than ìjust picturesî but then you have the images in digital form

There are other options like this now

Digital Cameras

These cameras do not use film

They store impressions of light and dark (ìpicturesî) electronically (ie: digitally)

You ìuploadî these images from the camera to your computer

Digital Camera Pros

Pros

Ditigal Camera Cons

Expensive (but comming down)

Not as good a quality as a good scan (except at the high-end price range)

Still takes time to make them right

Bill Geraci and Sally Levin, Mentors