On Fri, 18 May 2007 20:52, you wrote: > On Fri 18 May 2007 17:29:27 NZST +1200, Carl Cerecke wrote: > > Look at the EXIF files in a hex editor, then write a python script to > > modify those bytes. > > A possible solution for tinkerers, but I would use a script which does > the same and is already there: exiftool. It's perl (eek), but being > purely a user that doesn't effect me. If exiftool doesn't do this > resolution job, then there's a fundamental problem with the problem, so > to speak. > > Then of course there's the question of why one wants to change those > values - no effect on the information in the image. Does some other > silly(?) program actually use these numbers? What for?
I am submitting an application form, and the organisation requests a head and shoulders greyscale jpeg photo. It needs to measure 28x30mm with a resolution of 300dpi. So, if you calculate the number of pixels in 28x32mm @ 300dpi you get 330x354 pixels. I have now produced a JPG of that size using ImageMagick from a 2560x1920 image from my camera. I know the dpi values are merely stored numbers, and don't affect the image data itself, but, if someone should look at them then they will see 300x300dpi instead of the default 72dpi. Some programs, such as IrfanView for example, will look at the dpi values to determine how to print an image "actual size". We could discuss the fact that I ought to be able to send an image of any size, and their printing tools should be able to crop and scale the image appropriately. But, since they have gone so far as to specify exactly what they want, I am sending them exactly what they asked for. This might have been a mistake on their part. They do also allow you to send a real photograph if you'd rather... Andrew
