Guidelines for

Working with Digital Images

 

Know what you want for the end result BEFORE you start.

Are you going to print your image and, if so, at what size? Attaching it to e-mail? Posting it on a Web page? Uploading it for photo sharing/printing? Including it in a slide show?

 

For printing or photo processing, digital images should be of high enough resolution to produce reasonable print quality.

 

Print Size

Minimum Image Required

Aspect Ratio

4 x 6

900 x 600 pixels

1:1.5

5 x 7

1120 x 800 pixels

1:1.4

8 x 10

1500 x 1000 pixels

1:1.5 (1:1.25)

 

Image resolution is measured in PPI (Pixels Per Inch). A pixel (for Picture Element) is a single point in a digital image. The more pixels, the higher the resolution (sharpness and clarity) of the image. Too few pixels and the image will be jagged or pixilated. When you want to print an image from a digital camera, shoot it at the camera’s highest resolution. While you can with software resample your image to approximate additional pixels, you will get better results when the original image resolution is as high as you need for the task.

 

High-resolution files can be huge in dimension (think pillow case/bedspread) and file size (hundreds of KB/even MB). This is good for printing and OK if you have the drive space.

For posting to Web pages or sharing by

e-mail, images should be smaller in dimension (no scrolling) and file size (fast downloads). Use a combination of resizing (reducing PPI) and file compression.
 

Screen/E-mail Image Size

 

File Size

50 KB

or less

Thumbnail

130 pixels

Small

180-200 pixels

Medium

300 pixels

Large

400 + pixels

 

With scanners and printers, resolution is expressed in DPI (Dots Per Inch). If scanning an image for print, match your scan DPI to your printer DPI. If scanning for e-mail or for Web posting, scan at 75 DPI. When scanning to print an enlargement, try this formula.

 

          Scan resolution = Printer DPI x (Final image width/Original image width)

 

For better enlargements, consider scanning negatives rather than the print. The HHICC Resource Center has a high-resolution slide and negative scanner available for members.

Text Box: For ongoing information about working with digital images, try these HHICC SIGs: Web Page & Graphics Design with Jolyn Bowler – 4 PM, 4th Tuesdays Digital Photography with Paul Wyss, Bob Pettit – 7 PM, 4th Wednesdays
 

 


Installing IrfanView:

 

·        Insert Floppy disk in drive.

·        Right click My Computer/click Open

·        Right click 3˝ Floppy/click Open

·        Right click Iview351.exe/click Open/click Next/click Next

·        At IrfanView Setup window, check JPG/JPEG (at minimum) and any other file types you want associated (opened) with IrfanView

Text Box: Note Keyboard Shortcuts in Menus: R = rotate Right L = rotate Left T = Thumbnails P = Properties I = Image information F =Fit image to desktop S = Save As Space = rotate through images Enter = view images Full Screen W = Slideshow Esc = close Full Screen/ Slideshow/IrfanView Shft+G = Enhance colors Ctrl+R = Resize/Resample Ctrl+Z = Undo F1 = Help (your IrfanView manual) Using IrfanView:

 

w        Options/Properties/Extensions
 (check files to associate with IrfanView)

w        To scan directly into IrfanView,
File/Acquire (Select TWAIN source)

w        File/Open
(Locate disk/folder)
(Click to Preview if Preview Active)

w        File/Copy
(Be sure to copy your digital “negatives”
 before working with your image.)

w        Select (drag holding left mouse button down)/
Edit/Crop

w        Image/Enhance colors
(Negative/Sharpen/Effects)

w        Text Box: File types: .JPG or .TIF for photos .GIF for graphics File/Save As/Options
(check JPEG compression slider)

w        Options/Set as Wallpaper

w        File/Print/Best fit to page
(Custom/Inches/Preserve Aspect Ratio)

w        Text Box: On the ‘Net: http://www.irfanview.com http://IrfanView.homestead.com E-mail: searobin@yahoo.com Image/Resize(Resample)
(match pixels to result)

w        File/Save As/Options
(compress for e-mail, Web posting)

w        File/Slideshow