putting images on the Web that can be panned and zoomed

Bob Rasmussen ras at ANZIO.COM
Mon May 21 11:17:11 EDT 2012


There are two issues here, the quality of the image, and the tools for 
zooming and panning. You have received some good suggestions for the 
latter, let me dwell on the former. 

I would concur that you should start by scanning in grayscale. You will 
get a much more "zoomability". You might even increase your scanning 
density.

Then see if you can remove the speckles. Are they on the original? If you 
use a different scanner, or reposition the microfilm, do the speckles stay 
consistent? If not, then it's a scanning problem. If they ARE on the 
original, most image-processing software will have a filter for removing 
speckles. The filter should be adjustable for sensitivity, so you can 
avoid removing too much of the original document.

The lines probably ARE on the original, a result of running the film 
through the reader many times. You might find a filter to remove those, 
but that would be harder to find than one for speckles.

Then apply a threshold filter. Adjust it so the background goes to pure 
white. This will improve compressibility.

These are just some ideas. If you will post a higher-res grayscale image 
of one page, I'll play around with it.

Finally, I note that a Google search for "best practices scanning 
microfilm" produces a number of promising links.

On Mon, 21 May 2012, John Fitzgibbon wrote:

> Hi,
> 
> We are in the process of making very old hand written documents 
> available on the Web. The handwritten information has been typed up and 
> converted to HTML, but we are hoping to provide links from this to the 
> originals which will be in PDF format.
> 
> The originals are on microfilm. Each page is about six times as wide as 
> it is high. We have scanned a sample, but find that when zooming in, it 
> quickly becomes impossible to read the handwriting. Vertical lines which 
> are on the microfilm become more of a problem when enlarging the image. 
> Also, because of the document's dimensions, much of the document 
> disappears off screen when zooming in, and a large scrollbar appears at 
> the bottom of the screen.
> 
> A cleaner image and an ability to pan and zoom with the mouse would be ideal. What is the best way of achieving this? Any help would be much appreciated.
> 
> Regards
> John
> 
> 
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Regards,
....Bob Rasmussen,   President,   Rasmussen Software, Inc.

personal e-mail: ras at anzio.com
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