Specify the units – I seem to remember having a problem when I omitted this option (although DPI should be the default), for example: convert. convert -units PixelsPerInch -size x xc:black -resample 96 The GIF format actually totally ignores/discards the dpi anyway, as you can see diff finds. #resample. As for your screen — measure it! it is typically (these days) 90 to dpi. Remember dpi.
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Am I getting something completely wrong? For this purpose, it is just a a few number stored within the image file.
Sign up or log in Sign up using Google. So-to-speak I “executed” your code manually. If you want to print the original 72×72 pixels image as a 1 inch wide square, but at dpithen you’ll have to rescale the image in this case scaling it up. Do you want to 1 Change the real pixel dimensions of the image or 2 Change the metadata hint that is embedded in the image?
How to figure it out: I’m going to guess that these are for passport photos of some sort?
Some other image formats JPEG? I discovered that pngcrush not an ImageMagick tool can also add the density metadata.
One example, where the resolution value noted by ImageMagick inside the image metadata is NOT honored by converg application is Adobe Photoshop. Funny enough, the same output comes for input. IT isn’t a problem that the quality will deteriorate, because the image is needed just for the process of making the document not for the document itself.
IF an image viewer understands it, it will render the image larger or smaller to meet that DPI request, but it will not change the image per se. These are the exact requirements for making some documents through electronic government. Select all convert rose: That is the first info. Under what conditions imagemagkck you need to have -units first other than for vector images?
Convert image to dpi – ImageMagick
It seems to work. I added some details now. A higher DPI will transfer more picture information into the raster format and hence preserve more details from the real original quality. Post as a guest Name. Passport photo itself they will make when I visit the office.
Why does ImageMagick always convert to 96 dpi? I am often doing that when I am working with LaTeX, or to be exact with the command pdflatex on a recent Ubuntu-Machine.