Thanks for your answers. Due to my newbie status I'm still somewhat confused but at least now have some information that I can use to experiment. I've noticed that when I've got images in a MS Doc file that is then saved as "Web Page, Filtered" the size of the file (htm) seems to drop considerably from the size of the Doc file. I've opened both Jpegs in my browser (Firefox > New Tab > Open File) and, while image quality looks similar, the size of the images are different - the smaller one is smaller and the larger file is larger. I then started a Word Doc and inserted both scanned images into it - the quality seems very similar (the lower PPI scan has less contrast) but the size difference (on the screen) seems to differ less than when the Jpegs are opened with the browser, which is probably a result of being displayed within a smaller context..
I saved the Doc file and it is 1.7 MB - opened it again and saved it as "Web Page, Filtered" and the file size is 1.71 KB. This surprised me as the size of the final htm file seems to bear no relationship whatsoever to file sizes of the images that it contains; to go from 1.7 MB to 1.71 KB is, I think, an order of magnitude, so it leaves me with the impression that I may as well "go nuts" and scan at a higher resolution from within the scanner (assuming that I don't run into problems with the images becoming too large for an e-reader screen).
I opened the MS web page file in Sigil and saved it as an ePub and the file size is 80.2 KB (all file sizes are taken from file properties > Size
. I opened Calibre and imported the ePub file, then opened it in the Calibre reader (my only reader) and, lo-and-behold, the difference in image size (on the screen) is negligible although the larger (scanned) image still shows better contrast.
So now I'm more confused; it seems as though scanning at a higher resolution has little bearing in terms of final file size in terms of MB's of either the web-page file or the ePub file (which was my initial concern, not wanting the ePub to balloon to an unmanageable size) and has negligible impact on the visible size of images in the e-book reader's screen - after all, one image was scanned at twice the resolution of the other. So for the time being, I'll assume that scanning at 300 PPI is acceptable unless someone can explain otherwise. I’ve uploaded the ePub file if you’d like to have a look at it.
A few comments were related to “target device” but a look at the Wikipedia page for e-book comparisons (
http://en.wikipedia.org/wiki/Compari...e-book_readers) lists about 130 different models which makes for a rather diffused target. Beyond that, people will be reading e-pubs on smart phones and tablets and, especially with regard to tablets, with better and better (and bigger) displays, image quality starts to become more important than it is with dedicated e-readers.
My feeling is that the storage capacity on e-readers and tablets is something of a rip-off in a world where Gigabyte thumb drives are a dime-a-dozen and I suspect that these flash drives will increase dramatically in size once manufacturers have milked us sufficiently and one of them comes out with a device with reasonable storage capacities at a reasonable price. At that point, perhaps my concerns about larger ePub file size will be similar to worrying about what will fit on a floppy disk.
I looked for ULead SmartSaver but it is now part of Corel and sells for around $70.00 which is more than I would like to spend, although it seems as though it would be a helpful solution.
I do have Irfanview installed so I’ll experiment with that – it is worth my while to try things out before setting out to scan 150 images. I’ll also try saving as PNG to see if that helps rather than Jpegs.
Thanks again for your suggestions and please keep them coming if you feel you have something that would help to educate me.