Scientific Visualization Image Scanning

and Editing Tutorial

This is a tutorial for scanning and modifying images in Adobe Photoshop 3.0. When entering the .information provided here is equally applicable for use with Adobe Photoshop 2.0, since both versions share many common features. This tutorial is by no means a manual for scanning and editing images in Adobe Photoshop. Rather, it is quick reference of tips and pointers that future classes may find useful in creating and posting images on the World Wide Web.

For more information, see the Adobe Photoshop Version 3.0 User Guide located in the Laboratory for Scientific Visualization.


Scanning Images

The Laboratory for Scientific Visualization in Handcock Hall, there are PC & Mac Computers that Have scanners hooked up to them, (two PC computers). For this project a PC computer was used because all of the peers of the group working on the project owned PC computers. (Lab assistants can help you locate the appropriate computers.) Before you open Adobe Photoshop you should make sure the scanner is on and ready to scan. Once the scanner is ready (usually is indicated by a green ready light). To open Adobe Photoshop on Windows 95' click on:

Start > Programs > Adobe > Adobe Photoshop 3.0

This program has many capabilities, for this reason the first setting you must check is the TWAIN_32 Source. This is done by clicking on:

File > Acquire > Select TWAIN_32 Source

and make sure it is set to Microteck Scan Wizard (32 bit). Once Adobe Photoshop has loaded you may either edit an already existing image or you may scan in a new image. To edit an existing image, choose:

File > Open

and open your image from the appropriate disk/directories. To scan in a new image go to:

File > Acquire

submenu and choose the appropriate plug-in module for the scanner you will be using. In our case, we chose the TWAIN_32 option. While the program is loading, load your image on the scanner and close the lid. Make sure the image is aligned straight, (if using a book, you may want to place another book on top of it to ensure the image is flat on the scanner). Looking back at the monitor there are three windows. The first:

should be set to automatic. This box will control the initial color, contrast, size, and resolution of your image. All of these things can be modified latter. The second box is a window for your image.

By clicking on the preview button it will do an initial scan of your image. The third box is your tools box.


Click for more information on the tools

The move cursor will already be in the image window as a dashed lined box with your picture. With you mouse you may position the box appropriately around the exact image you want. Once the box is where you want it click on the scan button and it will scan that image that is in the cursor box only. (Scanning may take a we minutes.) A window will pop up with your image. You may scan as many images at a time as you wish, (we recommend that you only do few at a time so you can save your work as you go). You may not edit your image while the preview window is open. At this time close the preview box by clicking on the X in the upper right hand corner of the preview box.

Editing and Formatting Images

Once a new image has been scanned or a previously saved image has been opened, Adobe Photoshop may be used to edit the image. We recommend scanning images at a resolution of 144 pixels per inch. If your image is in color or is unusually large, you may wish to select a ower resolution to keep the file size reasonable. Remember: it is usually better to scan the image in at a higher resolution than what the final image resolution will be (see Resolution Basics) Link.

Resolution Basics

Image Resolution

Image resolution refers to the spacing of pixels within the image and is measured in pixels per inch (ppi). The higher the resolution, the more pixels in the image. Higher resolutions allow for more detail and subtle color transitions in an image.

Resolution and Image Size

Image size describes the physical dimensions of an image. Because the number of pixels in an image is fixed, increasing the size of an image decreases its resolution, and decreasing its size increases its resolution. For example, doubling the resolution of an image from 72 to 144 ppi reduces it to one quarter of its original size. Halving the resolution, for example, from 300 to 150 creates an image that is twice its original dimensions.

If you keep the image the same size, increasing the resolution requires Adobe Photoshop to create new pixels that can make the image appear blurry or out of focus. Because of this, increasing the resolution often produces a poorer quality image than the original.

Other Selected Formatting Tools

These are tools we found particularly helpful:

Under Image > Adjust > Rotate:

The Rotate command allowed us to align the images horizontally. The Rotate command can also rotate selections, such as text, for aligning with vertical axes.

Under Filter > Blur:

Blurring was usually the last operation we performed on an image. Like anti-aliasing in text, blurring helps smooth out rough edges created a more aesthetically pleasing image.

Under Image > Image size:

In the image size box you can control the amount of spaced that the image took up on a disk by adjusting the width, (the height adjust automatically), and the resolution, you can see the size.

Under Image:

there are submenu for Bright/ Contrast, Color/ Balance, and Hue/ Saturation. All of these techniques are self explanatory once opened.

Information on image formats


Table of Contents


Submitted by Michelle Gallagher

Virginia Tech Materials Science and Engineering

http://www.eng.vt.edu/eng/materials/classes/MSE2094_NoteBook/97ClassProj/visual/scanning.html

Last updated: 5/7/97