TIFF files indeed can be large.
But having looked at the quality of JPGs delivered by irfanview, compared
with the rather involved method I described, the irfanview version looks to
have more compression artifacts. But perhaps there is a way to persuade
irfanview to deliver better results that I haven't explored yet. The
smaller file size of JPGs may be a reflection of lower quality or lower
resolution. Jpg compression is "lossy".
I am given to understand that PNG is a format that offers a similar
compression but is claimed to be "lossless".
I think it would be good to take one pdf file containing an image and
export it in several ways and compare critically for image quality, before
adopting one method.
Pdfs can literally contain a jpg or jpgs, the pdf acting as a kind of
wrapper, and there are tools that can pull these out without loss. That is,
recover the original jpg completely. I have used such a tool but I removed
it when it stopped being supported.
It goes without saying that if you have received a document in ANY form,
PDF or otherwise, even TIFF, you should retain this unaltered, even if it
isn't the form that you attach to the family tree program. If need be, it
can be stored on a separate drive.
On 25 October 2017 5:55:44 pm Peter at LostCousins <peter(a)lostcousins.com>
> I don't know what other people experience but when I saved a
> a Heraldic Visitation file, composed of scans from the book, it saved
> as a PDF of 87 KiloBytes. I then exported this (on an Mac) as a TIFF
> file, and it came out as 15.6 MegaBytes, around 189 times larger. I
> know that TIFF files can e compressed but if people are not careful
> they may end up filling their disk and their genealogy files rather
> too quickly.
All the more reason to use JPG, perhaps?
In my tests a 1.26MB PDF death entry from the GRO turned into a 127KB JPG
Irfanview's default settings); though even saving the image as an
uncompressed TIF resulted in
a small saving in file size (1.12MB).
Unfortunately Irfanview isn't available in a native version for the Mac,
but it might run under a
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