On Tue, 30 Jun 2009 15:03:23 -0400 John Culleton <[email protected]> wrote:
| On Monday 29 June 2009 09:13:16 pm Anthony Thyssen wrote: | > On Mon, 29 Jun 2009 16:37:28 -0400 | > | > John Culleton <[email protected]> wrote: | > | On Monday 29 June 2009 12:00:30 am Anthony Thyssen wrote: | > | > On Sun, 28 Jun 2009 17:35:57 +0200 | > | > | > | > Noel da Costa <[email protected]> wrote: | > | > | Hi, | > | > | | > | > | Thanks... what I did was open it into Photoshop, which | > | > | reports the resolution as 300dpi. | > | > | Perhaps Gimp would do the same? | > | > | > | > BOTH would be faking it!!! | > | > Just as IM does. | > | > | > | > | > | > All of them are raster image processors. | > | | > | Therefore in Gimp one can increase or decrease the dpi figure | > | and run the dimensions up or down as you go. The converse is | > | not true for some reason. | > | > What do you mean the converse is not true. Of course it is true. | > | In IMageMagick perhaps. In Gimp no. The resolution remains constant | if you adjust the dimensions, meaning that it is doing some | downsampling or other conversion under the covers. It is just a | Gimp peculiarity. The basic rule, that size is inversely | proportional to density holds. But to adjust size without | converting the raster image I have to | adjust the density. For example I can scan a photo at 600dpi, and | then decrease the dpi to get a bigger image at 300 dpi. That is called -resample convert photo_at_600dpi.png -resample 300 photo_at_300dpi.png IM will do the resize and density adjustment so these two images still remain the same size in real world terms, though pixel size is halved. See Im examples http://www.imagemagick.org/Usage/resize/#resample Anthony Thyssen ( System Programmer ) <[email protected]> ----------------------------------------------------------------------------- I don't make the rules... I just impliment them! -- Programmers Law of Policy ----------------------------------------------------------------------------- Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/ _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
