Scanning Guidlines

Determine the output size and resolution

Resolution and image size are issues that most novice scanners overlook. In order to get the best scan possible you need to know 2 variables before scanning.

1. The physical size of the scanned image. Commonly measured in inches,
   centimeters, etc.
2. The resolution of the image, correctly expressed as Pixels Per Inch or PPI. Note: this is not the same thing as DPI or Dots Per Inch but is often incorrectly labeled as such. DPI is a printing function — how many dot per inch your printer is capable of printing…Without making this any more confusing than it already is here’s some guidelines:

Web output 72 PPI

Digital presentation output 100 PPI

Wide-format poster output 100 PPI

PowerPoint 35mm slide output 150 PPI

Publication/Journal output 300 PPI

Dye Sublimation printer 300 PPI

Set size and resolution

Scanner interfaces allow you to set your size and resolution requirements. It’s important to note that scanned images are bitmap in nature and not vector based. Once an image is scanned changing the size or resolution results in a reduction in quality. Information must be discarded or interpolated to create a new image size.

Adjust the preview marquee to crop the image

Fine tune the cropping using the marquee to select how you want the image to be scanned.

Scan the image

Hit the button!

Sharpen the image

Use Unsharp mask in Photoshop to sharpen your scanned image. Find this in Photoshop under Filter, Sharpen, Unsharp Mask. There are many variables that affect what the settings should be, try experimenting and use the preview window to see the results of changing the amounts. Use the values shown as a starting point.

 

Adjust color and desnity

Many color management issues affect how you adjust your scan. Important consideration—just what is your monitor doing??

Suggestions:

If you’re scanning for web, bring up a web browser and adjust to match.

If you’re scanning for slide output have one imaged and adjust your monitor to
match the slide. The same procedure can be applied to printer output.

Using the variations feature in Photoshop is a great basic way to adjust the color and density of an image. This can be found under Image, Adjust, Variations. There are more advanced methods for tonal adjustment that can be found in the Image, Adjust menu selection. Try exploring the Levels and Color Balance options.

Variations offers a visual ring around with color and density.

Remove any defects

Use the Clone tool in Photoshop to remove dust and scratches. It copies an area that the user defines and "Paints" that information where specified. You can control the size of the brush to customize the area of correction. To select a copy from area select this tool and hold down the option key and click. Then move to the area that requires the correction and click to apply.

Save the image

TIFF, PICT, and JPEG are very common digital file formats. If you’re importing your file into Powerpoint use PICT and avoid compression. For Web scans use JPEG and choose your level of compression carefully. More compression will save you space but will reduce image quality. For publications the most commonly requested format is TIFF. All three will go from Mac to PC, check your specific application for the recommended file type.