[olug] resize with gimp

Ken emptymm at cox.net
Thu Jan 22 17:01:45 UTC 2004


Nate wrote:
> When I go to the resize menu in the GIMP and at the bottom of that menu 
> is something called resolution.  If I take, say, a photo of a size about 
> 70 resolution and bring it down to 5 I get a smaller file but not a 
> smaller picture and do not lose any quality.  How can this be?
> 
> Also when I send that picture to windows and call it up with Paint Shop 
> Pro it reports in the resize window that the resolution is 5 as you 
> would expect however when you use that resolution part in the resize 
> menu in Paint Shop Pro to make the original picture a 5 resolution all 
> you get is a postage or Thumb nail picture.
> 
> Can someone tell me what is happening here ?
> 
> thanks,
> Nate
> 

My understanding (which is limited here) is similar to what Jay said. 
When you adjust the resolution you are adjusting the dpi of the image. 
You are loosing quality but it would only really show when it comes to 
printing the image since computer monitor resolution usually only 
displays at 96dpi (which is crap in print quality).

For example, if you started with a high quality 4x6in photo scan at 
600dpi and a high quality printer, it would print you out a nice 4x6 
photo.  If you were to reduce the resolution to 300dpi then it would 
need to print out at 2x3in to get the same photo quality (or at 4x6 with 
only half the quality).  Either way, it's going to look the same on your 
96dpi monitor.

As far as the Paint Shop difference, it could be that Paint Shop is 
displaying the "actual print size" of the image which would vary with 
the resolution. Adobe Photoshop has an option like this..

-Ken MacFerrin




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