On Sat, 2009-05-30 at 08:00 -0700, James Cobban wrote:
> I scanned some microfilm yesterday.  For some reason the software does not
> support JPEG so I scanned into TIFF format, putting 5 images in each TIFF
> file to reduce the number of times I had to enter a file name.
> When I got home I used GIMP to extract the individual images into JPEGs. 
> Unexpectedly the JPEGs are enormous!  For example one of the TIFF files that
> was 5MB in total, containing 5 images remember, exported into JPEGs which
> ranged from 9.0MB to 9.6MB!  That is using the default 85% quality.
> This is unexpected since TIFF uses lossless compression while I have
> indicated to GIMP that I would tolerate some quality loss.  Even when I
> reduced the quality to 65% the JPEGs were still over 5MB each.
> Are there any suggestions on how I can get GIMP to construct reasonable
> sized JPEGs?

There may be some obvious answer o your question I don't know about.  I
hope someone provides it.


It is hard to evaluate your question without knowing some more about the

What size was the original tiff file?
What were the pixel dimensions of the individual subimages which you
wanted to save as jpegs?

What size would they be if you saved them as tiff files?

Among other things, jpeg only compresses significantly if there is
sufficient redundancy in the file to do so.   If that isn't so, it is
conceivable you might not get that much reduction.  How about showing us
one of those images?
Leonard Evens <l...@math.northwestern.edu>
Mathematics Department, Northwestern University

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