Manipulating Print / Document Size Issue

[markurxn]

I am trying to create a .5 x .5 inch thumbnail with Imagemagick. Theres a huge quality difference between what I am doing in Imagemagick versus what I can do in Photoshop. I'm new to image manipulation, so I could be missing a step. The image attached illustrates the steps I'm taking for each method and it shows the resulting image.

In Imagemagick, I'm cropping / resizing while keeping the dpi at 300. What I'm not able to do is set the document size. My command looks like:

convert -density 300 -thumbnail 120 -crop 50x40+55+15 input.jpg output.png

In Photoshop, using the crop tool, I can set the print size and crop to 150 pixels wide at 300 dpi.

It looks to me like its a document / print size issue. Any ideas?


http://64.182.1.86/gd3/shrinkingquality.jpg

-Mark

[fmw42]

Take a look at -resample http://www.imagemagick.org/script/comma ... p#resample and http://www.imagemagick.org/Usage/resize/#resample

I am no expert at this kind of thing, and I will defer to the experts, but I think this may be what you need.

[anthony]

You are just enlarging a small image using IMageMagick.

You need to crop and resize the image with regard to the final 'density' you are using for output. IM defaults to a 72 dpi density
whcih is reasonable for displays, but horible for printouts!