> So, I have used Gimp to downsize large architectural drawing images
> from Tiff's to jpgs. Well, I always thought I was downsizing them.
> In the past, the process always seemed to make the files more usable
> in the application where I need to use the architectural drawings
> without a significant loss in quality.
> This morning, I have had trouble following 'my process'. Typically, I
> will open a tiff in Gimp, save as jpg, export if prompted, then select
> quality of 40 or 50 percent, and the result is a usable file that is
> significantly smaller than the source tiff file.
> Today, the source tiff which is 900 mb in size is being converted to
> jpg which is 6 or 7 mb in size, totally unusable.
> Additionally, if I simply open the source in Gimp, save it to another
> directory from Gimp without making any changes, the file also grows to
> 6 or 7 mb.
> What am I doing wrong this morning that I have not been doing wrong
> for the last 6 months?
> I am stumped (and frustrated because I have work to do).
> Using version 2.6.11 in Ubuntu 10.10 if that matters.
> I have a version of 2.7 on my Windows XP OS, and it will lock up
> trying to open these drawings.
> It's curious, because, at 900 MB, I typically can use the drawings
> without even altering or downsizing them. Today, it's a problem.
> What I really cannot understand is why Gimp is causing unaltered files
> to grow in size when saving them. Is that normal?
There are tiffs and tiffs, see
http://en.wikipedia.org/wiki/Tagged_Image_File_Format, however what
happens if you save to png first, rather than as a tiff as defined by
gimp (where some compression may have been removed).
If you save to png, I would be interested in the resulting size, and
then if you convert to jpg from that, what size is the jpg.
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