Administration Guide : Setting up Xinet Volumes : Fine tuning preview generation

Fine tuning preview generation
Xinet ships a preset, default preview-generation values. Many sites may find the Xinet-set values appropriate. You may, however, change these settings for any individual volume at any time. Any change, however, will only affect newly-generated previews, not those already in existence, unless you specifically update them (through the Update Previews tab).
Xinet allows you to fine tune the ways in which it automatically generates its For Placement Only and Web-ready images on a volume-by-volume basis:
There are several ways to open the Preview Settings panel for a volume.
Starting at the Volumes/Users, System Volumes, Summary tab, hover with your cursor over either a check mark in the FPO or Web columns. You should see the check mark highlight itself in blue.
Click on a highlighted check mark. It doesn’t matter which column. They both lead to the same page.
Click on the Volumes/Users, Systems Volumes, Preview Settings tab, and select a volume in the Select a Volume pop-up list.
Figure 0-3 Preview generation options. The “Set as default options” button may alternatively be “Discard options (revert to defaults).”
For more information about preview options, also refer to the fpovolpts(4) man page, either online or in Volume 2, as not all of its options appear in the GUI.
Note: The options you set for Preview Generation may be set for the individual volume you are currently configuring and also, optionally, established as the default values that will be assigned to any volumes added in the future.
This feature may help retain detail in dark (shadowed) areas in FPOs and previews if you also enable ICC color transformations on the volume. (See Color profiles for Xinet previews.) Success will vary according to a number of factors, so it’s best that you test in an environment where the images are likely to be previewed.
Note: the integer value stored in fpovolopts(4) will be 10 times the DPI.
Default is 0, for example, the option will not be used.
By default, Xinet creates EPS FPOs for EPS files and TIFF FPOs for all other image formats. The Make EPS FPOs option makes it possible to generate EPS FPOs for all types of images. You might want to use this option when Mac users primarily use applications such as Adobe Illustrator, which doesn’t write OPI comments for TIFF FPOs, or if you have Windows clients within your workgroup. EPS FPOs also preserve the link to the high-resolution original image on the server when they are taken off site. The fm key takes one of three possible values:
eps = make EPS FPOs from all image types
noconv = make EPS FPOs from EPS or PDF files, make TIFF FPOs from all other files unless an image contains a clipping path, spot colors or mask
web = make Xinet-style Web previews
When on, Xinet will make previews for raw camera, GIF, and ArtPro CTs.
By default, FPOs are copy protected. Turning on this option makes it possible to export EPS FPOs without using the Xinet FPO Exporter to explicitly break links to high-resolution corollaries. This can be done safely for EPS FPOs because they contain path and file ID information; TIFF FPOs do not, however, so be aware that breaking their links will cause confusion. Use this in conjunction with the fm key.
Note: The integer value stored in fpovolopts(4) is 10 times the DPI.
You might want to turn on this option when you know Mac users primarily use applications, such as versions of Adobe Illustrator, which only recognize EPS files and you are sure they won’t need printable previews for the low resolution images (for example., when they print proofs it won’t matter that they see gray boxes where the images should be). Printable EPS previews take extra space on the server and have an impact on performance.
This option is mutually exclusive with other FPO resolution constraints because Bounding Boxes do not carry a concept of resolution.
Turning on this option will cause Xinet to insert PC-style TIFF previews into EPS FPOs. See the Xinet PC Connectivity Guide for more information about OPI replacement on Windows workstations.
When on, Xinet will not insert the Standard OPI “ALDImage” comments into FPOs.
By default Xinet will not JPEG-encode EPS FPOs unless the high-res files are already JPEG-compressed. In some cases, however, you will see that the FPOs are not smaller than the originals. To overcome this, Xinet includes the option to JPEG-compress all EPS FPOs, at three quality levels, Low Quality, Medium Quality, and High Quality. You will get smaller FPOs this way (the lower the quality, the smaller the FPO). Using one of these settings will not effect the quality of the high-resolution image at print time; it will only change the FPO.
Include masks in EPFS FPOs via a PostScript Level-3 Masked Image operator. These FPOs will produce PostScript errors when printed to a PostScript Level 1 or 2 device. This option key overrides em.
Xinet, however, also generates PICT previews. You may turn off this option or choose between palleted (8-bit) previews, Full color (the default setting), or Full color (OS9) previews. Please check your Macintosh application documentation to see whether PICT previews are used by particular applications your users run. PICT previews are used, for example, by the Aldus Fetch image catalogue program. They are also used to provide screen previews for EPS FPO images. (Without them, Mac users will see gray bounding boxes.)
The Xinet 8-bit setting builds palleted previews (including masks) which look acceptable on most kinds of monitors. Full color previews provide more detail, although, of course they take more memory. These previews look better on full color monitors. Full color previews differ from Full color (OS9) previews when the high-resolution image has a mask or clipping path: they present more intricate masks, which have the potential to crash OS9 clients.
This will ensure that JPEG WEB previews contain either an ICC profile from the high-res image (if that high-res is RGB and contains a profile already) or the ICC profile selected to represent RGB previews on the server (if set). If you use this feature, that profile will be embedded in the JPEG preview and then allow properly-equipped applications and browsers to display the preview based on ICC color transformations. (See Color profiles for Xinet previews for information about color fidelity in other sorts of previews.)
You may also limit image resolution by DPI or DPCM. By default, Xinet sets this value to 72 DPI. You may, however, type in other values. The values stored in fpovolopts(4) are 10 times the DPI.
If you want to limit the pixel dimensions of WEB previews, check the box for this option and include a value in the type-in box. In some instances the value you set here may override the resolution for Web previews. That’s because, even at the selected resolution, some images can be too large to fit in a Web browser window. This option limits an image to a specified number of pixels.

The strings shown in this column are keys used by fpovolopts(5)

Set options for this volume
Saves the currently displayed values for the volume.
Set as default options
Saves the currently displayed values for the system, so that each new volume thereafter will, by default, initially have these values.
This option toggles between Set as default options and Discard options (revert to defaults) depending on whether the stored options for the volume match the stored default options.
Dismisses the currently displayed values in favor of the values last set for the volume.
After changing options, the Update Previews page, described in the following topic Updating previews, will open automatically. This allows you to ensure that all of your images will have previews generated in the same way. If you do update previews, older previews may work in a different fashion than new ones. The Update Previews page will open with appropriate previews already selected for you.