Sharpening files for digital printing

[RPNugent]

I recently bought an Epson 3880 printer and have a minor question about file sharpening for the digital printers here. In the past when I sent files for printing on a Lightjet I used something like amount 350, radius 0.3 and threshold 0 based on what Calypso printing had in their specs when I took a class there before they started printing on Epsons. Does the same apply to inkjet printers like the 3880?

So far I must say that I’m pleased enough with the results to know that my CP51 processor has become a very expensive paperweight. Don’t know if anyone might be interested in it.

[Francisco Disilvestro]

I follow the recommended setting by Bruce Fraser in the book "Real World Image sharpening with Photoshop CS2" to print with a 3800.

For a 360 DPI file, amount 360, radius 0.6, threshold 4

The method described in the book uses a sharpening layer overlayed to the image and using a high pass filter.

[Brian Ellis]

I use different settings for different photographs and different sizes of the same photograph but my most common is for roughly 8x11 landscapes and that's radius 1, threshold 0, amount ranges from about 80 to about 130 depending on the amount of detail in different areas of the image.

However, I select areas of more or less uniform tone and don't sharpen them at all (the sky for example). And other areas in the image get a greater or lesser amount depending on the degree of detail in them. But I never go over about 130 for the amount. At the radius I use my prints look over-sharpened at a greater amount. And I don't recall ever going below about 80 for landscapes. This isn't as complex as it may sound, there usually are no more than three areas and often less that get different degrees of sharpening plus areas like the sky that get no sharpening.

I think you have to just try different settings and make prints. I don't think there is a standard setting that works for all prints. After a while you start getting a pretty good feel for the right amount to use (I don't vary radius or threshold). You could also try one of the several sharpening programs out there. I tried one and didn't think I got better results than I got on my own but some people like them a lot.

[Marko]

A quick way to get (approximate) preview is to view the image on screen reduced (zoomed out) to either 50% or 25% of the full size. It is important to use one half progression only in order to eliminate sizing artifacts, i.e. 50%, 25% or 12.5% and stay away from intermediate steps such as 66%, 33% and such.

The reason for doing this is that screen display needs much less sharpening than the print, since there is no ink dissipation (dot gain). Zooming out in halves effectively discards half of the pixels in each axis and so approximates the effect of dot gain.

Finding the right zoom-out level for the given printer - or even paper and ink set - will take some experimentation, but this could be a handy, fast tool.

[Michael Gordon]

Sharpening should be image- and size-based. A one-size-fits-all approach is a compromise. How do I determine sharpen settings? Proof prints

[Francisco Disilvestro]

There are different approaches, but the three steps sharpening workflow described by Bruce Fraser is:
Input sharpening: To compensate for aliasing of the low pass filter in digital cameras or scanners, so is dependent on the capture device no matter what is in the picture
Content / creative sharpening: As other posters mentioned, depends on every picture
Output sharpening: To compensate for aliasing of the print method, so it is dependent on the output device and not on image content. What I wrote in my previous post is output sharpening for an inkjet printer at 360 DPI and that is independent of image content.
ACR from version 4 and Lightroom sharpening are based on the method proposed by Bruce Fraser for input and content sharpening

[RPNugent]

Thanks Brian and Francisco for the helpful suggested starting points.

I had found the Calypso lightjet settings gave me what I felt were slightly soft prints on the 3880 so was wondering what others were using. It is interesting to note that using your very different suggestions resulted in indistinguishable (at the 8x10 size), but very nice and sharp while not overly sharpened prints that were quite different from what I was getting with the settings from Calypso's lightjet suggestions.

[Preston]

"Sharpening should be image- and size-based. A one-size-fits-all approach is a compromise. How do I determine sharpen settings? Proof prints

Same here. This method does use paper and ink, but is more efficient in the long run, imho. (I use an Epson R2400)

The starting points given above are similar to mine, and will get you close.

-Preston

[D. Bryant]

Sharpening should be image- and size-based. A one-size-fits-all approach is a compromise. How do I determine sharpen settings? Proof prints

Michael's advice is spot on.

Some people recommend Photo Kit Sharpener or Nik Sharpener Pro 3.0, among other products. I've tested both PKS and NSP and fianlly purchased NSP 3.0.

Some suggest using PS built-ins for output sharpening. The PS/Lightroom evangelists-gurus like Jeff Shewe, Andrew Rodney, Eric Chan and others recommend PS to Lightroom for printing to optimize sharpening which utilize Photo Kit technology.

Based on my own experience I don't recommend judging sharpness that your monitor displays if you are outputting to paper.

Good luck,

Don Bryant

[sanking]

[QUOTE=Brian Ellis;536687You could also try one of the several sharpening programs out there. I tried one and didn't think I got better results than I got on my own but some people like them a lot.[/QUOTE]

I use Photokit Sharpener, which has routines for Input, Creative and Output sharpening. It was designed by some very good people, including Bruce Fraser, and works really well, though if you have some understanding of how it works you can get even more out of it. On the whole I am fairly certain that in 95% of the cases PK Sharpener does a better job than I could do on my own.

My only major complaint is that it only works with RGB files and virtually all of my work is with grayscale images.

Sandy King