Juhana wrote:

...

for free access. [For those interested, the book is the 1885 second printing of the second edition of Sir Richard F. Burton's "Kama Sutra of Vatsyayana".]

Please do *not* make them bitonal (black and white only)!!!!!!! You could also save time and do only the color manipulation (e.g., "gamma").

I do not intend to throw away the original page scan images, or the partially cleaned up greyscale "intermediary" images (which have been deskewed, fully cropped, and have been normalized onto a white background canvas.)

Could you place all the original scannings available for me? I could place the scannings available at our site. I also would like to process the images myself before you ruin them.

Again, I'm not throwing away anything. <smile/> But I do understand your view that original page scans should be: 1) done at archival quality and 2) made available to the world.

Use of "gamma" most likely is not the way to improve the images. I will pick up the two example images and do experimentations. Takes a few days before I mail again with results. I have earlier done this kind of automatic level blancing in which I additionally flattened the curved pages (dark near the binding).

I agree with the "gamma". I've been spending a lot of time experimenting with the feedback provided by quite a few people on how to further process these images. A goal of mine is to produce a portable yet nicely readable DjVu version of the scans, and from past experiments going from 600 dpi greyscale to 600 dpi bitonal, and then putting that into DjVu, works out pretty good. The DjVu readers have their own "built-in" anti-aliasing to improve readability. But I'll experiment some more on the 2-bit versus 8-bit approach for DjVu. Regarding "curved" pages, I did mention before the book was "chopped", so each page is now separate and was scanned with minimum distortion.

Are those original 8-bit images?

The originals were scanned at 600 dpi optical and greyscale. Some have mentioned I should have scanned at full 24-bit color since sometimes certain color channels (such as red and green) have lower noise and thus improve image processing/restoration. My experiments yesterday confirmed that the red channel was a little better, but doing various post-clean-up experiments showed that, at least for my copy of the Kama Sutra, the red channel versus grey-scale did not visibly improve the final results. Of course, there may be books where color channel separation could give remarkable improvements in post-processing, so, except for increased space requirements, it may be preferable to scan at 24-bit, even for black and white documents.

How to download them from DP? What are the direct links to the pages?

I'm not sure if I can give out the ftp user:pass at 'dpscans', since it was given to me in confidence. If you are interested, email Jon Niehof <jon_niehof@yahoo.com> for possible access since they were dumped into his folder, 'jnik' (he's on travel, so has limited access the next week or two.) The raw scans total about 1.22 gigs, while the partially cleaned-up scans (still 600 dpi greyscale) take up about 680 megs. Jon Noring