sharpening for print

I searched the NPN site for relevant articles, but now ask my question here. When processing an image in Lightroom, my approach is to increase sharpness as much as possible, consistent with no visible sharpening halos and minimal noise, using a combination of the sharpness, noise reduction, and masking sliders. I sometimes use the adjustment brush in areas such as sky or water where lack of sharpness is not critical to apply more aggressive noise reduction there. (My camera is a Canon T3i and the sensor is not famous for its low-noise abilities.) If I'm posting it on NPN, I use Tony Kuyper's resize and sharpening actions. This results in an image that looks quite good to my eye when viewed in a web browser; better than if I had just resized it in PS and done no additional sharpening. TK's sharpening definitely improved its appearance. But if I'm having the photo printed, say to 18 - 24 inch size, I don't do any more sharpening than I already did LR. But I wonder if there is some additional sharpening analogous to TK's that would improve the printed image. Any opinions? My photographic subjects mostly fit in the landscape gallery.

Before you try and fix what may not be broke, are you currently pleased with the sharpness of your prints?

Yes, I hear what you're saying. The motivation of my question was a comparison of an image resized in PS and the same image resized and sharpened with TK's actions. The latter not only was sharper but appeared to have more "depth", for lack of a better word. So I was wondering if my prints could look "better" with some additional processing specifically tailored to printing. What do you professionals do when preparing an image for an 18 - 24 inch print?

Ron: Sharpening for Print is a bit of a different beast than sharpening for the web using TK's actions. His actions are really nice for web presentation, but Tony will tell you (and I think he says so in his documentation) that those actions are not intended for print output.

Print output has many other variables that I consider when sharpening. If I'm printing on a cotton fiber based paper (largely matte surface) the dot gain from the paper will be more than if I'm printing on a luster or glossy surface paper. Generally (but not always), I can apply more aggressive sharpening when the final output will be on a matte surface. Of course the size of the print also impacts the sharpening parameters to be used. I use Nik Sharpener Pro for some work, I use Smart Sharpen or Unsharp Mask for some work. It seems to depend on the image what seems to produce the best output. If you are shipping the file out to a printing company, make sure you know if they intend to apply any sharpening or if they assume you've prepared the file as desired.

A bit tough to be really specific in answering your question as sharpening is a pretty detailed (no pun intended) subject for optimal quality, especially when it comes to prints.

Agreed with Keith that it's tough to be specific, since many factors [should] affect how you sharpen. A big one is resolution. When outputting for the web, you're typically working a lower resolution and smaller dimensions than for print.

I mainly use Photoshop for sharpening. When outputting for the web, I sometimes use Tony's actions, while other times I'll do it 'by hand'. Most web images I size for 1024px wide at 72dpi (sometime 150). I apply sharpening at a smaller radius than for print, by as much as 3-4X.

Bottom line, the sharpening processes for web vs. print are distinct from one another.

Hope this helps.

I size for 1024px wide at 72dpi (sometime 150)

Note that the 72dpi here is completely meaningless Wesley and won't affect your image. It's simple a piece of meta data that some programs/print drivers can use as an initial default. You could set it to 72000 and your image would appear identical.

For printing, I tend to find that a little over-sharpened can sometimes produce a better result to account for ink spread on paper. As Keith mentioned, you can get away with more on a matte or art paper. I've spent some time making some test cases on a single print, one of which is shown here with three different sharpening methods on the same print. I printed this one about 16x12; All three sections came out OK, but I definitely got better detail on the "crunchier" looking one on the right. But that's from a couple of inches away, and the difference isn't huge. It really depends on how anal you are about this.

Here's a trick I use when sharpening for print in CS6:

Set the rulers in PS so that they read in inches.
Now, grab a real ruler and hold it next to the screen, aligning an 'inch' mark.
Adjust the view so that 1 inch on PS's ruler is the same as 1 inch on the 'real' ruler.
Sharpen your image.

Note: When you size your image, set the print resolution to your printer's 'native' resolution. For Epson printers, this value is 360 dpi. I believe the reason for this is so that the printer does not have to do any interpolation.

I use USM or Smart Sharpen in Photoshop for printing. The specific settings are image dependent, as has been mentioned. I agree with David that the on-screen image should look a little crunchy (over-sharpened); however, you'll need to check for halos by going to View>View Actual Pixels.

Once I have the image sharpened, I save the file and then flatten it before printing. After I am done printing, I go to the History palette, delete the flattening step, and re-save the file. It's always a good idea to run a hard proof print to see if the image needs further tweaking for color, contrast, or sharpening.

The bottom line is as John mentioned: If it ain't broke, don't fix it.

Added: Here's an article from West Coast Imaging about gaining maximum sharpness from digital camera files that may be of interest.

--P