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emco: english >Know-how >Computer and Internet >Image processing for the Internet >Working with IrfanView >
Working with "IrfanView"A brief overview of the functions on the toolbar
Opening an image file and fundamentals
Important program functions  | Creating cropped images
| | Saving an image and assigning an image format
| | Brief information about the most frequently used image formats
| | Editing colors
| | Changing the image size
| | Filters
| | Specifying the order of images/working with thumbnail view |
IrfanView is a multitalented program and very interesting freeware that can be obtained on CD-ROM in numerous magazines or via the Internet. The program only measures approx. 640 KB. In addition to the download, there are a number of plug-ins that substantially expand the regular scope of functions: IrfanView can also be used to play back audio files (Real, MP3, WAV) or apply certain Photoshop filters.
The current version of the program is located at: www.irfanview.com After the installation, you can start Irfanview by double-clicking the Irfanview icon (see the figure above). Always use the options provided by the toolbar in navigating through the program. This allows for direct access to the most important program functions. In addition, many of the symbols (icons) are familiar from other Windows programs. A brief overview of the functions on the toolbar: 
1. Open
2. Slideshow
3. Save
4. Delete File
5. Cut selection
6. Copy
7. Paste
8. Undo
9. Image information
10./11. Zoom in/out
12./13. Previous/next file in directory
14./15. Previous/next page
16.Current directory index
17. Properties
18. About IrfanView Several of these functions will be referenced below. Most of the other functions are either easy to understand or well-documented in the online help of IrfanView. Opening an image file and fundamentals
Open the first image in the "Image"-folder. (All of your photographs should be stored in this folder.)
To do so, select the "File" menu and the "Open" menu item or click on the corresponding icon. Select the Image- folder, mark the first image, and click on "Open".
If your pictures are larger than the screen, you can adjust the images to fit the window. It is recommended (if at all) only to adjust the large images to fit the window. To do so, select:
"View" menu, "Display Options" menu item, and mark "Fit only big images to window".
However, it is better to display images in their original size. If the image does not fit into the Irfanview window, you can also reduce the display of the image: | Repeatedly press the minus key (-) on the keyboard.
| | Repeatedly press the magnifier symbol (-) on the toolbar (10./11.).
| | You can quickly return to the original size by pressing "CTRL+H". |
IrfanView offers a series of convenient functions that facilitate work with greater numbers of images. For example, you can scroll through existing images in a directory. The following example shows image no. 2 of a total of 51 image files of the selected directory. Using the two arrow keys (previous/next), you can scroll forward and backward in the directory.
In addition to the icons, keyboard shortcuts offer a fast way of selecting functions of the program: | The spacebar offers another option to move to the next image in a directory (but not to return!).
| | Scrolling forward and backward is also possible by using the arrow keys on the keyboard.
| | The Enter key toggles the full-screen mode on and off.
| | "+" enlarges the display.
| | "-" reduces the display (see the symbols 10./11. on the toolbar)
| | Shift + G Enhance colors |
Most of the keyboard shortcuts can be viewed via the pull-down menus to the right of the command word. An overview of the keyboard shortcuts is located in the online help. Important program functionsWe do, however, want to take this opportunity to deal in detail with a few of the program functions that are important for our work: 1. Creating cropped images
With many images, you only need certain sections of the image for your work. IrfanView offers a quick way of creating a new image from an image area:
Press and hold the left mouse button on the image, drag the desired image area, and release the left mouse button again. An image area is marked (see the figure below; the marking lines are highlighted for illustration purposes).
Next select the "Edit" menu and the "Crop selection" menu item. The selected image appears as a new image.
Important: Do not save at this time! Otherwise, the original image is overwritten. Observe the following processing steps.
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Marking and crop selection
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2. Saving an image and assigning an image format
To save the new image, select: "File" menu and "Save as" menu item. Enter a name and assign the file type "jpg" to the image. For our purposes, we need a slim image format. These are, among others, "GIF" or "JPEG" files which are also widely distributed on the Internet. 3. Brief information about the most frequently used image formats
GIF displays an image with up to 256 colors. JPEG with up to 16.7 million colors, and JPEG features the strongest data reduction. The reduction parameter can be set by using the "Options" button. The higher the image quality, the lower the data reduction (compression), the larger the file size.
A qualitatively high JPEG is more brilliant than a GIF. GIF allows, for example, transparency switching of certain color areas of the image. Other important image formats are the Windows bitmap format "BMP" and the TIFF format "TIF". However, these two formats are too large for presentations or a web presence. They could possibly delay the image display or page change since they require too much memory. TIFF files are used in professional digital photography since TIF represents an image without loss. | | |
A brief example is shown here:
The figure on the left is required as JPG with a quality level of 80% and it takes 1.47 KB (1507 bytes) of memory. The same file as bitmap (BMP) is almost 10 times the size: 10.02 KB (10,262 bytes).
IrfanView can be used to quickly and easily change image formats:
You merely save an existing image via "File" menu – "Save as" menu item and select the desired file type. 4. Editing colors
Another powerful function, which is often also perfectly suited to rescue images that are too dark or too bright, is the possibility of color-editing the images:
"Image" menu and "Enhance colors" menu item
or via "Shift+G" shortcut
After selecting the program function, another window opens that offers the most important color change options via slide controls and, which is particularly practical, immediately displays the changes in the "New image" window.
"Brightness", "Contrast" and "Color balance" (Red, Green, Blue) should be familiar from your home television set. But "Gamma correction" may be new. It can be used to control the brightness distribution of the image.
The two figures below show the gamma correction by means of a gradient:
The left side shows the linear gradient, the right side the corrected gradient: By using gamma correction, the image brightness is changed so that the dark and bright image sections remain unchanged, yet the image appears brighter or darker without affecting lights or shadows. Use the possibilities of visual control over the two small image windows (original image, new image). If you briefly want to transfer the changes to the original, larger display in the editing window, click on the "Apply to original image" button. Returning to the default values is accomplished by using the "Cancel" or "Set default values" button.
If you made any changes, do not forget to save! 5. Changing the image size
Another frequently required function is the option of changing the image size. However, in doing so, you should always visually check the result. Depending on the file format (tiff, jpeg, ...), extreme image size changes (in both directions!) result in a loss of image information, or details that are unavailable due to compression move to the background.
"Image" menu and "Enhance colors" menu item or via "Shift+G" shortcut (see the figure below).
The setting options are, once again, fairly self-explanatory. It is important to select the "proportional" setting, if needed. In this case, you only specify the value for the desired width or height for enlarging or reducing. The missing value is automatically calculated by the program.
The "DPI" (dots per inch) setting represents the number of image pixels per square inch on the screen or on paper (if it is printed). For this purpose, it is helpful to know that computer monitors display with approx. 72 dpi. You should select at least 150 dpi to print it out as a photo. In our case, 72 dpi are sufficient.
6. Filters
Even though IrfanView is free of charge for private users and education, it does provide powerful filters for image editing.
The most common one is the sharpening filter (sharpen) which is primarily applied after changes in size. Other interesting filters are located under "Effects".
You should simply try out the selections. As long as you do not save, you are not damaging anything. AND: Today's objective is the presentation of images and the integration of image and sound. For this reason, you should not be too critical with your designs!
7. Specifying the order of images/working with thumbnail view
After you have read in and edited all your images, it is useful to prepare the images for selectively copying them into the presentation program (PowerPoint). There are several procedures available. We suggest sequential numbering to arrange the images in the desired order.
IrfanView offers a digital image panel that allows you to gain a quick overview of all images in a directory: the so-called "thumbnail view".
Select "File" menu and "Thumbnails" menu item.
The thumbnail view opens with two different windows next to the program window: the directory tree and the directory view, the actual image palette whose display size and type can be changed under the "Options" menu and the "Set thumbnail options" menu item.
The directory tree corresponds to the left window of the Windows Explorer. It displays the complete directory structure of your PC. Double-clicking a thumbnail image displays every image in the editing window of the program so that it can be edited.
Next, specify the image order of your presentation by renaming the images so that they can be displayed on the screen in the desired order. The images are sorted in alphanumerical order on the image palette. For this reason, we suggest sequentially numbering the required images for the presentation: image01.jpg, image02.jpg, ...
1. Select the desired image on the image palette with the right mouse button and select: Rename (see the figure below).
2. Enter a new name for the image, for example "Image01.jpg".
Caution: Do not overwrite or add the file extension (.jpg) yourself!
Note that a file name is always specified according to the following convention:
Suffixes identify file types and assign them to the corresponding programs: .doc = Word, .htm = browser, jpg = image.
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