- Open the image in photoshop
- Cmd+J/Ctrl+J to duplicate the layer, and then open the layer styles window, then alt + click the sliders to split the white blend, move the two of them to 235 and 250, and the same to the black layer, but to 10 and 20, then using the opacity controls in that window to adjust the amount of sharpness that is visible.
- Then under filter, sharpen and unsharp mask, use the values 320%, 0.6, 4. for Amount, Radius and threshold, respectively.
- Then to edit, fade unsharp mask, and opacity to 76%, and mode luminosity.
- then change the blend mode of the layer to overlay
- then go to filter, other, high pass and change the radius to 0.6/1.0 to 2.0
- once that is done, zoom in on the finer details and turn the sharp layer on and off, to check if it has worked well or not.
This is a good method of making sure images are good to print on a large scale.
