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Working with Images: Finding, Creating and Using Digital Images Goals

Choose the best image resolution and file format given a desired end product for an image

Understand how image resolution and file format of images commonly found on the web restricts their flexible use

Understand the capabilities and optimal uses of each scanner in the Arc

Understand scanner TWAIN drivers compared to bundled scanner software

Knowledge of basic image manipulation most commonly needed for scanned and digital pictures

Why are resolution and file format important? Resolution is the number of dots per inch of ink or monitor pixels that make up an image. In

general, the higher the resolution, the more detail you have about an image. The more detail you have about an image, the larger you can make it without experiencing quality problems.

However, the total number of pixels of information (not just the resolution at which the image is stored) you have to describe an image will limit how large it can be displayed on a monitor or in print without quality loss.

• Monitors display 72 pixels per inch

• Printers generally print between 300 and thousands of dots per inch

When scanning, choose your resolution based on the end goal for your image

• For all on-screen viewing, 72-100 pixels per inch is sufficient

• For print, 300 pixels per inch is usually sufficient

• If you intend to increase the size of a digital picture after scanning, double the resolution each time you want to double the final image size.

Common file formats include JPEG, GIF, TIFF, Photoshop, and PDF

• End goal is on-screen viewing: JPEG for photos (lossy), GIF for line art

• End goal is print: TIFF or Photoshop for photos, PDF for text documents

• Archived copy: Try to maintain a copy in Photoshop format so that you have flexibility to make changes at any time

Resolution and file format are important because they determine what you can and can’t do with an image.

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What kinds of images are available on the web? Most images are 72 dpi JPEGs and GIFs optimized for on screen viewing (small pixel

dimensions)

• If you resize them, they will look jagged and poor

• If you print them, they will look much worse than on screen

Images found on the web are best used on screen only, unless otherwise specified

• Images are property of their copyright owner and not free, should ask permission

Ways to find images

• Google image search – http://images.google.com ; all will be free, most will be screen quality only, but pixel dimensions are listed

• http://www.freeimages.co.uk/ has nice, free stock photography, but you are required to credit them in print or on web; these are print quality not just screen quality

• Getty Images has line art and stock photography that is available for a fee per picture - http://creative.gettyimages.com/source/home/homeCreative.asp

What can people scan in the Arc? Photos Documents Film negatives

Slides Print documents

What scanners are available in the Arc?

A high-resolution color scanner (Agfa DuoScan T2000XL, capable of scanning at 4000dpi optical resolution, with Acrobat’s built in OCR software) • This scanner is best used to scan color images into Photoshop for digital image

preservation or high end color print reproduction • It was used by the library for the Dred Scott digital archive

A high-speed grayscale scanner (Fujitsu M47097D, capable of scanning up to 50 ppm with grayscale output of up to 800dpi, document feeder for automated duplex scanning) • This scanner is best used to create Adobe Acrobat PDFs of print documents • It is the same model as the one that the library’s reference department uses to prepare

documents for eReserve

A slide and film scanner (Nikon Coolscan LS 2000, capable a maximum of 2,592 x 3,894 pixels, maximum optical resolution of 2700dpi) • This scanner is best used to scan color images into Photoshop • It can only scan slides and film

Eight basic scanners (HP Scanjet 4570c, capable of scanning at 2400dpi optical resolution, with basic OCR software) • These scanners are best used to scan color or black and white images for use on the

screen, web, or consumer level color printers (e.g. inkjet printers) • They can also scan print documents but for more than five pages, they are not

recommended

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Using Photoshop CS3 to Improve Scanned or Digital Camera Images We will learn how to correct the following common problems with scanned pictures:

Scanned image is huge and does not fit on the screen Scanned image prints poorly and looks all jagged Image needs to be rotated and/or cropped Image is blurry There is a blemish on someone’s face or on the picture Image is underexposed or overexposed Image has a color cast

Image needs to be rotated and/or cropped Sometimes when you scan, the picture isn’t straight on the scanner bed. In order to correct this, you need to first rotate the image and then crop off the excess space surrounding the image. You can also apply the same cropping techniques if you just want to crop a photo.

To better understand rotate and cropping, please open the file rotate.tif from Arc Documents (t:\).

Click on the Eyedropper Tool to reveal the menu that allows you to choose the Measure Tool. First, we’ll use the Measure Tool to draw a line along the edge of the picture. This line tells Photoshop what we want to be level horizontally.

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Next, select Image > Rotate Canvas > Arbitrary… The resulting dialog box will look like this:

The angle will be automatically filled in, based on the line you drew in the last step. Click on OK. You image should now be straightened out, but there will probably be a lot of extra white space around the edges. You need to crop that space out.

Select the Crop Tool from the toolbar. Use this tool to draw a box around your picture. Everything you didn’t enclose in a box will appear gray and will be eliminated from the picture when you complete your crop. Adjust the box so that it has only the part of the image you

want to keep. Double-click in the box to crop away the gray area.

Scanned image is huge and does not fit on the screen You already learned about resolution in the scanning portion of the workshop. Remember, if you are only going to view your image on a computer monitor or a TV, the resolution does not need to be higher than 72 pixels/inch (also called dpi or dots/inch). If you want to print your image, a dpi of 200-300 is recommended. To better understand resolution, please open the following two files from Arc Documents (t:\).

Go to Image > Image Size and your resulting dialog box will look similar to this:

We will adjust the resolution and see how it affects the Pixel Dimensions and the Document Size.

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There is a blemish on someone’s face or on the picture If someone has a blemish or if there is a scratch or dust on your scanned image, you can fix the picture using the Healing Brush Tool. To better understand the Healing Brush Tool, please open the file healing-brush.tif from Arc Documents (t:\). Select the Healing Brush Tool from the toolbar. At the top of the screen, select a brush size that is similar to the blemish you want to remove. Holding down the ALT key, click on an area similar to the one you want to heal. Position the brush over the blemish and click once.

The blemish should magically disappear!

Image is underexposed or overexposed

It is also very common to have an image that is over or underexposed. It is very simple to correct this problem using the Levels function of Photoshop. To better understand Levels, please open the file too-bright.tif from Arc Documents (t:\).

After you have opened the image, select Image > Adjustment > Levels… from the menu bar. The resulting dialog box should look like this:

When an image is under or over exposed, you will see a lot of white space to the right or left side of the histogram. Click on Auto and the picture will be automatically changed to reflect the levels that Photoshop thinks are optimal. If your picture is still too light or too dark, you can adjust the sliders directly below the histogram until the picture looks best to you. Click on OK when you have finished.

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Image is blurry Depending upon the quality of your image, you might be able to increase the sharpness of your image and remove some of the softness or blurriness. This is accomplished using a filter called Unsharp Mask. To better understand increasing sharpness, please open the file blurry.tif from Arc Documents (t:\).

Go to Filter > Sharpen > Unsharp Mask… The resulting screen will look like this:

You can play with the options to see if it improves your image, but I usually just keep it on the default option. When you click OK, the image should look sharper and clearer.

How do I scan?

Note: Every scanner has a different driver, or TWAIN interface. In the Arc alone, we feature four different driver interfaces. You can usually access the TWAIN driver from more than one program, such as Adobe Acrobat, Adobe Photoshop, and the software that comes bundled with the scanner.

If you are interested in learning how to use any specific scanner in the Arc, you are invited to stop by for the Arc open house this Friday from 11:30am-3pm. You are also invited to stop by the Arc any other time to receive personalized scanner training.

Demo in Open Technology Area: Tour of the Arc’s scanners (time permitting)