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.

Author: Tojagis Nasida
Country: Botswana
Language: English (Spanish)
Genre: Automotive
Published (Last): 13 January 2010
Pages: 267
PDF File Size: 20.82 Mb
ePub File Size: 18.39 Mb
ISBN: 840-5-26065-948-3
Downloads: 39159
Price: Free* [*Free Regsitration Required]
Uploader: Zulkikree

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. The image I put here, is from Windows command which is working fine but if I execute the same command on the same image then its not showing required DPI. Passport photo itself they will make when I visit the office. If you answer questions just by title you are not a help to anyone here.

Did you even understand what I tried to say in my comment?! So it asks you at which resolution you want to print.

For example, following is a C program compilable via gcc setRes. Should I try again, but in different words? Imagemayick Questions Tags Users Unanswered. But this is no more than a ‘hint’ attribute that does not alter the underlying raster image. With ImageMagick you cannot print.

Trying to reduce the DPI of a image – ImageMagick

Post convfrt a guest Name. You can ‘print’ the very same 72×72 pixels image on a 1 inch wide square: Just convert DPI to metric: It seems to miagemagick. If you ‘manipulate’ your image with Gimp, and then embed the result in LaTeX, the page looks imagemagjck you expect it.


A higher DPI will transfer more picture information into the raster format and hence preserve more details from the real original quality. So-to-speak I “executed” your code manually.

It has no influence upon inagemagick number of actual pixels described by the file and is completely irrelevant in this respect. Sign up using Email and Password.

Now there are different algorithms which can be used to compute what color values these 4 pixels 3 of them new pixels should have:. Also, ImageMagick does not support ‘printing’ as such. DPI is only meaningful if rendered to devices. ImageMagick does not touch this profile, even when asked to write a resolution change into the metadata of an image file.

Whatever is noted as ‘Resolution’ or ‘Density’ inside an image file, is a metadata attribute. Post as a guest Name. It is just a hint which a printing or rendering device or an application may or may not follow when printing, rendering or displaying the image. Now there are different algorithms which can be used to compute what color values these 4 pixels 3 of them new pixels should have: So there actually was no effect at all.


Do you know which embedded data fields GIMP uses to read the resolution – does it have its own that override the standard ones used by ImageMagick?

It’s a completely abstract value that gets practical value only in the jmagemagick of knowing also the absolute size of the printout or rendering on imaggemagick or monitor: If you ‘print’ it at dpi on a 1 inch square, it’s no longer the same image: The problem is that density is also a ‘input setting’.


One example, where the resolution value noted by ImageMagick inside the image metadata is NOT honored by an application is Adobe Photoshop. For every 1 pixel in the original you’ll need 4 pixels of the new, upscaled image. The OP should have chosen the heading: 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?


Please provide the following to resolve the above issue: PNG image data, x8-bit grayscale, non-interlaced output. That’s the reason why you made this discovery: Nov 28 ’16 at Vonvert it is still not clear to some readers what I noted above, here is one more attempt Sign up or log in Sign up using Google. Email Required, but never shown. I would probably have expected something similar with units, in which case order between the two should not matter. Select all convert -units PixelsPerInch image -density resultimage.

Convert image to dpi – ImageMagick

Sign up using Email and Password. Since ImageMagick is known to be superb and I used it for many other tasks I tried to achieve my goal with this tool. And ImageMagick’s documentation is in full agreement with me: This gives you This is new to me.

Try to avoid resampling unless you are hurting for speed. Some other image formats JPEG?