[magick-users] Tiff to PNG speed, and advice on Q16 vs Q8

[Anthony Thyssen]

Roland Tanner on  wrote...
| Hello,
| 
| As mentioned in quite a few other posts, convert can be slow in converting 
| images between one format and another, depending on setup. I am experiencing 
| very slow processing. (Admittedly I'm working on an underpowered laptop, 
| which does not help).
| 
| Can I get some advice? I have about 1000 tiff images, of about 500KB each, so 
| not vast as far as tiffs are concerned. They are monochrome from microfilm. I 
| want to convert them to pngs suitable for website display - so resize and 
| then convert them. 
| 
| Unfortunately the files were converted on some proprietary Windows based 
| scanning platform - opening them in the GIMP crashes KDE! However they are 
| not corrupted. I have put some version info at the end of this message. Note 
| the 'unknown field' report at the end, which every image has.
| 
| The advice I need is:
| Will using Q8 rather than Q16 decrease the quality of the resulting image?
|
Generally no, but it depends on the destination format which you did not
mention.

| Would resizing first and then converting be better/quicker than doing in one 
| convert command?
|
Resize during the read process rather than afterward.

| If I want to use Q8, am I going to have to compile it?! Would I have to 
| unistall Q16 first? I'd rather apt-get, but I can't see it in my repos.
| 
No. just get the source and build a new one.

See IM Examples, Feedback and Questions
   http://www.imagemagick.org/Usage/feedback.html#speed

It is very general however.

Also specialized programs may be faster, such as  tif2gif  from the 
libtiff package, as is is more specific, than a generalised image
processor.


  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
 -----------------------------------------------------------------------------
    Personally, I consider myself perfect and bug free...bug free... bug
    free...  bug free... bug free... bug free... bug free... bug free...
        -- Adam Calinsed Cuerden   <acuerden at salsgiver.com>
 -----------------------------------------------------------------------------
     Anthony's Home is his Castle     http://www.cit.gu.edu.au/~anthony/