Sharpening for printing

I have learned from experience (and have also seen others comment to the same effect) that one needs to sharpen a digital image more for printing than for viewing.

But now much? With sharpening for viewing you can just look at it and tell, but how do you know how much too sharpen for printing - too much and it will look phony, too little and it will be soft.

???

Thanks,

G

Well, I usually sharpen up a tiny bit more than what looks optimal on my computer monitor. Also, the amount and type of sharpening I use depends on paper size and type.

For example, a 4X6 inch matte-finish print needs little extra sharpening, as details are smudged up anyway due to the matte finish. However, an 8X10 glossy-finish needs more work applied. For these, after performing all other edits (i.e. cloning, cropping, colour balance, etc.), I apply very slightly more sharpening than what looks good on my monitor.

The larger the print, the more likely people aren't going to come up an inch away to view. I personally wouldn't worry too much about sharpening, trial-and-error is a good way to learn what settings, paper sizes, and paper types work best. The shop used for printing can also play a major role in print quality.

G, a little math magic works wonders here. Measure the width of your monitor's display, in inches. Multiply by 75. Find the display resolution closest to that result, and switch to it.

Now when you open the image, set the view (I'm assuming you're using Photoshop or Elements) to 25%.

Now, you've set your screen resolution to 75 ppi, and Photoshop is displaying one out of every four pixels. That means that the image on your screen has an effective resolution of 75X4, or 300 ppi, same as your printer. Now you can actually eyeball your sharpening amounts.

If you have a large enough monitor, you can try setting it to 150 ppi, and using a 50% view. Just stay away from Photoshop's 33% and 66% views- PS adds a lot of anti-aliasing to these views to make them work, so the image is softer in these views.

Also note: This method is only effective if you're reducing your images to print size (1800X1200 pixels for a 4X6, for example). If the printer has to reduce the image size, then it's going to reduce the width of the sharpening halos also. If you're not comfortable with reducing the image size, then you'll have to factor the reduction in to determine sharpening amounts.

- Joe U.

Thanks guys.

Alex, I'm pretty much doing the trial and error thing already. Just need a more scientific method. But I like your insights: seems reasonable that smaller prints would need less, but also that 8 x 12s or something usually mean that they are framed and not gotten that close to (but not always - portfolio shots would be examined in hand and very closely).

Joe, wow, I will have to re-read that a few times! (I think I've been working too hard lately cause after work some things just don't click very fast :) .) I am reducing the size. One thing to note (if I understand): LCD screens display well at their max resolution but very poorly (fuzzy/blurry) at smaller resolutions, so I will have to see how that works in the instructions you have here. Will try it and see.

Thanks again!!!

G

I hadn't heard that G, but it does kind of explain a variable I couldn't nail down. The closest I'm able to get with my 17" MacBook's LCD screen is about 80 ppi( Using the 1152x720 res). I would have thought that that meant the image would be undersharpened if you were going by the screen, but I find that, if anything, I need to back the amount off- just a tad- to make the print spot-on.

Still, I find that this system gives me a reference point to work from. I'd be interested in your thoughts on it, if you try it.

- Joe U.

So G, any thoughts?

- Joe U.

Hey Joe -

Haven't had time to try it yet, being a little busy at work and other stuff. I did drop off a few images for printing and found that I didn't sharpen them enough, so the problem still exists. Maybe this weekend I'll go through you procedure and see how it goes. Poke me again next week

G