I wrote last week about the DjVu format that’s among the formats supported by Internet Archive, and why it’s so good for displaying books with pictures. In this post, I’ll detail how to take advantage of DjVu’s picture-viewing capabilities.
For the most part, DjVu is well–documented. It’s widely acknowledged that the DjVu format excels in the online presentation of images/pictures, when compared with PDF, but this is not emphasized as much as it should be. In most discussions of eBooks, the emphasis is on text, and pictures are an afterthought.
This under-emphasis of commentators about the capability of DjVu in presenting books with pictures/images is perhaps related to the fact that the DjVu system itself has surprising design lapses that make it hard for the user to intuit the system’s graphic capabilities.
These powerful graphic features are especially related to use of thumbnails, which are much of what makes DjVu so useful for viewing books with pictures.
The thumbnail bar, shown to the left, is the key to navigating the pages of a book. The first hurdle in using this is that, oddly, the default display when a book is first displayed does not show the thumbnail bar. To turn it on, the user has to click the Show/hide thumbnail icon, which hides inconspicuously on the far right side of the toolbar. Turning on the thumbnail bar display can also be done by right clicking anywhere and choosing Layout – Thumbnails (In another odd, unaccountable oversight, the Show/hide thumbnail icon does not appear at all on the toolbar in the Macintosh -Safari version of DjVu, and the user has to use the right-click [or CTRL key] option to turn it on.)
The default display of the thumbnail bar is quite small, so the next step in using it to get a better view of page contents is to enlarge the size of thumbnail images, by dragging the mouse, as shown at left.
The thumbnail bar works smoothly — Thumbnails are loaded rapidly as the user scrolls down to see more. Surprisingly the speed of loading seems to be little affected when the size of thumbnails is enlarged. It’s odd that the default size of images in the thumbnail bar is so small, when the larger size works so well — Another indication, I think, that the DjVu developers are not thinking much about use of the system for viewing books with pictures, since it’s so much easier to see details in pictures with larger thumbnails.
Finally, one more hurdle to using DjVu seems to exist in Internet Archive, which is the largest source of DjVu records — When the DjVu format is chosen in the “View the book” box, the link to open the DjVu file is broken. The way around this is to click All Files: HTTP, which is at the bottom of the “View the book” box. This goes to an index screen listing several formats, and clicking the one that ends in .djvu (usually the first in the list) successfully opens the file in DjVu format. I sent a question about this on Sept 8 to the DjVu.org forum, and have not gotten an answer on Sept 10 — Go here to see the question and to see if it has been answered.
Yogi Berra quote of the day: “You better cut the pizza in four pieces because I’m not hungry enough to eat six.”