Input Sharpening and Resolution upsizing

[kuau]

I need to upsize some of my images so I can maintain at least  180DPI for printing 20x30 on my Z3200 PS printer. I am shooting with a Nikon D700
For input and output sharpening I use PhotoKit Sharpener and for upsizing I have both Genuine Fractals and ALien Skin Blow Up.
My question pertains to workflow.
Do I first do a input sharpen on my image before I upsize it or so I do it after upsizing it?
I of course do output sharpening at the very end.

Thanks

Steven

[madmanchan]

Steven, input sharpening (or capture sharpening, as it's sometimes called) is usually done at the original resolution of the file, before image resizing. This gives you a use-neutral master file which can then be repurposes for different image sizes, as needed (e.g., web-sized images, prints of different sizes).

[jbrembat]

Steven,
 the initial sharpening is to try to recover the effect of the antialiasing filter (a low-pass filter).
 Must be performed at the original image size.

Jacopo

[bjanes]

Steven,
 the initial sharpening is to try to recover the effect of the antialiasing filter (a low-pass filter).
 Must be performed at the original image size.

Jacopo

That is true, but the Capture Sharpening as proposed by Bruce Fraser involves two processes. The first, sharpening for source, is to correct for softening introduced by the blur filter or by digitizing the image and is applied globally but limited to the midtones via blend if sliders. Sharpening for content takes into account the image content and is different for low frequency sources (e.g. portraits) and for high frequency images (e.g. landscapes). It is usually done with masking to restrict some of the sharpening to the edges. Both of these steps are performed at the original image size.

Bill