Save Image Options - JPEG 2000

Use the JPEG 2000 tab located in the Save Image Options dialog box to set options for the JPEG 2000 image file format. These options will then be taken into account every time you save images in JP2 format.

The JP2 method was developed to make so-called "Streaming" possible. "Streaming"is used, for instance, when images are loaded in the Internet and results in an image being built up progressively. This means that an image will be saved in the file in different resolutions.

Opening the dialog box

Select the File > Save As... command. Select the JPEG 2000 (*.jp2) image file format and click the Options... button .

Description of dialog box

Selecting the compression parameters

Define the compression parameters in the Compression group. To do so, select a compression method from the list, then enter the necessary parameters.

Note: As with most compression methods, JPEG 2000 creates image artifacts. The more an image is compressed; the more artifacts this creates.

Compression method - Quality

Select the Quality option in the list, to specify the quality of the image in a compressed file. Entering a high value in the Value field, will ensure that your images are of high quality. Even a relatively high value, e.g. 85%, considerably reduces the file's size. Depending on how detailed an image is, the file size can vary greatly when you use this method.

Compression method - Ratio

Use the Ratio option in the list, to keep the ratio of your source file size to that of your target file size, constant.

Enter the desired value in the Value field.

When the image file is 10 MB in size before compression, by a ratio of 1:25, the compressed file will then be about 400 KB (10 MB / 25 = 400 KB).

Compression method - Target size

Select the Target size option in the list, to specify the file size of the image in a compressed file.

Enter the required file size in KB, in the Value field.

Please note that using the Ratio and Target size methods can lead to results of differing quality when employed with images that have different grades of contrast. This can reduce the quality of highly detailed images.

Compression method - Lossless

Select the Lossless option in the list, to compress your image file without loss of quality. When you do this, all the image information will of course be retained. The size of the compressed file depends largely on the amount of contrast in the source image, but will anyway be far greater than when you use the other methods. Conversely, the advantage is, you can still Stream it when you use this method.

1004 20092012