Summary:

If you have 4 GB of RAM or more you should be able to process 250 MB images (CS3) to 350 MB images (CS4x64) without using memory tiling.  With memory tiling images up to 4 GB can be processed by dividing the image into sections or tiles, processing each tile separately, and then reassembling the tiles into the final image.

IMPORTANT: As you use Photoshop the RAM Photoshop accesses becomes fragmented. So if you have been using LucisArt 3 with no problem and then at some point get a “need to tile message” it means the RAM is fragmented. To defrag the RAM select Edit | Purge | All. Or you can restart Photoshop.

If your image cannot be processed in one pass, and you will be asked whether or not you wish to tile the image. Unless you are processing a huge image please avoid using memory tiling.  Tiling is slow and there can sometimes be artifacts at the edges of the tiles in areas of the image where the contrasts do not vary much, such as a clear blue sky. However note that with most images the contrasts vary enough that artifacts from tiling will not occur. Because of the possibility of these artifacts, you will be warned before the software processes any image that is large enough to require tiling.

Processing extremely large images with memory tiling in LucisArt 3 can be very slow. This applies not only to the actual processing operation (after you select OK in the user interface), but also to the process of actually showing the LucisArt 3 dialog. It is recommended that you experiment with LucisArt 3 settings on a smaller version of the image before trying to process the entire image. You can save some time by processing a small version of the image using your selected settings, opening the larger version, and using Photoshop’s “Last Filter” command (Ctrl-F on Windows or Cmd-F on the Mac) to bypass the LucisArt 3 user interface.

Troubleshooting Memory Issues

Even with tiling, the software still puts a heavy demand on the system’s available memory, and out-of-memory conditions are still possible. These instructions will help you to improve the software’s performance as much as possible when dealing with extremely large images.

If you should encounter a “not enough RAM” message, there are some things you can try in order to be able to process your image successfully.

1) Close any other Adobe applications, such as Adobe Bridge.

2) Defrag the RAM by selecting Edit | Purge | All. Or you can restart Photoshop.

3) Complete any operations that need to happen before the LucisArt 3 processing (such as resizing the image), save it to a temporary file, and then select Edit | Purge | All to defrag the RAM. Open the temporary file and perform the LucisArt processing without doing anything else.

4) If you are running a 32-bit version of Photoshop, try adjusting Photoshop’s “Available RAM” setting. This can be found in the preferences – on Windows, this can be accessed from Edit | Preferences | Performance, and on the Mac, it is at Photoshop | Preferences | Performance. The first thing to try is increasing the setting – this may make enough memory available for LucisArt 3 to complete the operation. If that does not solve the problem, try decreasing the setting. This is not entirely intuitive; why would reducing the amount of available memory solve an out-of-memory problem? The reason is that in some cases, LucisArt 3 is not actually running out of memory, but rather out of address space. Reducing Photoshop’s available RAM setting causes Photoshop to allocate less memory, leaving unused address space that LucisArt 3 can use to process images. This is not an issue if you are running 64-bit Photoshop CS4.

5) If none of the other measure has helped, consider upgrading your operating system and/or Photoshop version. Photoshop CS4 is significantly better at handling large amounts of memory than Photoshop CS3. If you are running Windows, the 64-bit version of Photoshop is even better. Running under 64-bit CS4 on a 64-bit version of Windows, the maximum image size supported by LucisArt 3 is almost unlimited.