Derivative creation and quality control process in DLG

Mary Willoughby at the DLG works closely with TCA on the imaging side of the project. Here's her description of the process she goes through when performing image quality control and creating derivatives:

"As part of the Troup County Superior Court Records project, I convert the document images scanned at TCA into PDF and DjVu images for online display. Along the way, I've been working with Kaye Minchew and the TCA staff to help review the images for consistency and quality and suggesting techniques and software options to help with their scanning process.

Once TCA sends us a disk (typically containing 500GB – 1 TB of tifs) I spot check its contents to make sure the scans are of consistent quality and are properly oriented and cropped. If there are problems that I feel would negatively affect usability in the finished page display I refer them back to TCA. When time and DLG workflow have allowed, we corrected some of these problems here using either BookRestorer (a batch image editing application) or a combination of ACDSee or XNView as a viewer plus Photoshop as an editor. Because of the large number of files involved in the project and the necessity of hand naming by TCA during their scanning process, I also double check the filenames using Quick File Rename, a batch file renaming program that we have found useful for many DLG projects. When fixing problem images at DLG is not an option because of other project demands, the TCA staff corrects scans they feel need improvement and sends us replacement files.

After any necessary changes are made to a set of images, I convert them to DjVu and layered PDF using the JRA Publish software suite. Both of these file formats allow you to greatly compress large images with minimal compression artifacts. They also provide page-turning, zooming, and the ability to print an enlarged version of the image you are viewing from within a web browser if you have the appropriate plug-in installed.

The final step in the DLG's role in managing the images is to move the master tif files to our archival storage system for long term preservation. Though a large amount of drive space is required for this, it is important because these images will allow us to recover from any accidental data loss that might occur in the future. Having a readily available set of high quality images for these documents also preserves our ability to undertake any conversion projects that might be necessary to preserve the usefulness of the collection should the files used to present the images become obsolete or be superceded by new technology."