rescale-shrink and keep pixels

[iaw4]

Let's say I have a document that is 10cm x 10cm at 72dpi. I want to shrink it to 5cm x 5cm at 144dpi. Later, if I want to scale it back up to 10cm x 10cm at 72dpi, I should not have lost any pixels.

how would I do this? advice appreciated.

/iaw4

[anthony]

that is JUST a density change use -density

Code: Select all

    convert image_72   -density 144  image_144