In OSX there is a tool called sips, it allows one to script image processing but I am sure you already know that if you're reading this!
In my case I am trying to resize the DPI from 144DPI to 300DPI without resampling the image. I know this is possible because the "Preview" tool allows this by unchecking a box, however, I cannot find anything anywhere on how to do this on the command line.
In short I would like to modify the DPI of an image without resampling it.
The code below works to change the DPI but it resamples.
sips -s dpiHeight 300 -s dpiWidth 300 *.tiff
I have tried giving it an expicit resampleWidth / resampleHeight of the images but that doens't work either. To be clear I want to keep the original dimensions of the images and just change the DPI - again I know this is possible because the "Preview" tool allows this inside "Tools -> Resize Image" (Uncheck resample image) and change DPI from 144 to 300
Thanks in advance, this should hopefully save me having to do each image one by one!