JPEG 2000 is a new addition to Photoshop’s list of file formats. It is a derivative of the standard JPEG format but offers additional enhancements.
JPEG 2000 advantages
- More control over the balance between compression and quality
- Ability to target a file size
- Can utilize optional lossless compression
- Support for16-bit color and grayscale images
- Retains alpha and spot channels
- Support for transparency in 8 bit-images
- Support using a Region of Interest (ROI) to selectively optimize portions of your image using an alpha channel
JPEG 2000 disadvantages
- JPEG 2000 files cannot be optimized using the Save for Web feature.
If you decide that the positives outweigh the negatives, then you need to know about the various options involved in saving a JPEG 2000 file. Note that the following options save the file in extended JPEG 2000 (JPF) format. There is also a standard or minimal JPEG 2000 format (JP2). After you click the Save button, the JPEG 2000 dialog box appears with the following options:
- File Size: You can enter a value to set a target size for the saved file. The Quality value will adjust automatically to the best quality for your specified size.
- Lossless: Select this setting to compress the image without quality degradation, but create a larger file. If deselected, you can drag the Quality slider to specify a quality setting. Higher values result in better quality but a larger file. But, if you select a quality setting that is inconsistent with your target file size, the File Size changes.
- Include Metadata: Select this option to include file information. Leaving this option deselected will produce a smaller file.
- Color Settings: Select this option to include ICC profile data. Leaving this option deselected produces a smaller file.
- Include Transparency: This setting preserves any transparency in the image.
- JP2 Compatible: Select this option to create a file that can be displayed in an application that supports standard or minimal JPEG 2000 format but does not support extended JPEG 2000 format.
- Advanced Options: Click this button to access the following options:
- Compliance: Chooses various devices that support this format. Right now only general devices, like browsers, are supported.
- Wavelet Filter: Specifies the type of numbers used to encode the file. Integer is a good overall option for providing good image quality. Float is more accurate, but you can’t use it with lossless compression. Float may also cause some degradation around the edges of an image.
- Tile Size: Specifies the size of the tiles used in the image. Use 1024 x 1024 for a good overall size. If you create a really small image, use a lower size.
- Metadata Format: Saves various data with the image. JPEG 2000 XML is format specific XML data, XMP is File Info data, and EXIF is digital camera data.
- Color Settings Format: Includes color settings data in the image file. The ICC Profile format option includes the ICC profile specified in the Save As dialog box. The Restricted ICC Profile option saves a restricted profile used for portable devices, such as cell phones and PDAs. This profile is for the JP2 format only.
- Optimization Order: Choose one of the following: Growing Thumbnail produces a sequence of small thumbnails that get larger until they reach the image’s full size.
Progressive creates an image that gradually displays increasingly detailed versions all applications. Color displays the image as a grayscale image first and then as a color
image.
- Region of Interest: As I mention earlier, being able to use regions of interest is one of the advantages to this file format. If your image contains one or more alpha channels (saved selections), you can choose them to define a Region of Interest. Select the alpha channel from the Region of Interest pop-up menu. Then choose an Enhance value to increase or decrease the quality of the Region of Interest relative to the rest of the image. Be warned that by enhancing the area inside the region, the area outside the region decreases in quality. This is done in order to leave the file size the same. After the alpha channel is used, it will be deleted when the file is completely saved.
- Download Preview: Choose a download rate from the pop-up menu. The estimated download time is displayed in the bottom-left corner of the dialog box if you selected the JP2 Compatible under JPF Settings.
JPEG 2000 advantages
- More control over the balance between compression and quality
- Ability to target a file size
- Can utilize optional lossless compression
- Support for16-bit color and grayscale images
- Retains alpha and spot channels
- Support for transparency in 8 bit-images
- Support using a Region of Interest (ROI) to selectively optimize portions of your image using an alpha channel
JPEG 2000 disadvantages
- JPEG 2000 files cannot be optimized using the Save for Web feature.
If you decide that the positives outweigh the negatives, then you need to know about the various options involved in saving a JPEG 2000 file. Note that the following options save the file in extended JPEG 2000 (JPF) format. There is also a standard or minimal JPEG 2000 format (JP2). After you click the Save button, the JPEG 2000 dialog box appears with the following options:
- File Size: You can enter a value to set a target size for the saved file. The Quality value will adjust automatically to the best quality for your specified size.
- Lossless: Select this setting to compress the image without quality degradation, but create a larger file. If deselected, you can drag the Quality slider to specify a quality setting. Higher values result in better quality but a larger file. But, if you select a quality setting that is inconsistent with your target file size, the File Size changes.
- Include Metadata: Select this option to include file information. Leaving this option deselected will produce a smaller file.
- Color Settings: Select this option to include ICC profile data. Leaving this option deselected produces a smaller file.
- Include Transparency: This setting preserves any transparency in the image.
- JP2 Compatible: Select this option to create a file that can be displayed in an application that supports standard or minimal JPEG 2000 format but does not support extended JPEG 2000 format.
- Advanced Options: Click this button to access the following options:
- Compliance: Chooses various devices that support this format. Right now only general devices, like browsers, are supported.
- Wavelet Filter: Specifies the type of numbers used to encode the file. Integer is a good overall option for providing good image quality. Float is more accurate, but you can’t use it with lossless compression. Float may also cause some degradation around the edges of an image.
- Tile Size: Specifies the size of the tiles used in the image. Use 1024 x 1024 for a good overall size. If you create a really small image, use a lower size.
- Metadata Format: Saves various data with the image. JPEG 2000 XML is format specific XML data, XMP is File Info data, and EXIF is digital camera data.
- Color Settings Format: Includes color settings data in the image file. The ICC Profile format option includes the ICC profile specified in the Save As dialog box. The Restricted ICC Profile option saves a restricted profile used for portable devices, such as cell phones and PDAs. This profile is for the JP2 format only.
- Optimization Order: Choose one of the following: Growing Thumbnail produces a sequence of small thumbnails that get larger until they reach the image’s full size.
Progressive creates an image that gradually displays increasingly detailed versions all applications. Color displays the image as a grayscale image first and then as a color
image.
- Region of Interest: As I mention earlier, being able to use regions of interest is one of the advantages to this file format. If your image contains one or more alpha channels (saved selections), you can choose them to define a Region of Interest. Select the alpha channel from the Region of Interest pop-up menu. Then choose an Enhance value to increase or decrease the quality of the Region of Interest relative to the rest of the image. Be warned that by enhancing the area inside the region, the area outside the region decreases in quality. This is done in order to leave the file size the same. After the alpha channel is used, it will be deleted when the file is completely saved.
- Download Preview: Choose a download rate from the pop-up menu. The estimated download time is displayed in the bottom-left corner of the dialog box if you selected the JP2 Compatible under JPF Settings.
The new JPEG 2000 in Photoshop
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