Posted by Karl Buiter on November 6, 2014 at 12:07 AM
A question for those who have printed large images at lower DPI's, and Output Sharpening. I think I am ok but to be sure...
I have a number of proofs at 300 DPI and 150 DPI when using a Canon Large Format 1200 dpi head. I use NIK Output sharpener set to the correct output and all looks great even up close.
I printed a proof for 100 DPI. At a distance of 4 feet, all looks great. I have some customers that want big; this one 48 x 27", so as long as its going up above the fireplace, sure.... But as I get closer to the print I see all the sharpening artifacts jump right out at me identical in appearance to the output sharpened source image seen on the monitor - super crispy!
What I assume is happening is the 300 DPI images, intended to be viewed closer, mix in the eye at a close distance. And the same result occurs for the 100 DPI image at the further 4+ ft distance. I was expecting coarser pixelation; but I am just surprised to see the sharpening artifacts.
So everything is ok?!
Posted by Paul DeCesare on November 6, 2014 at 12:17 PM
I battle those all of the time with 20x30 and larger, I'm actually glad to hear someone else experiencing that, lol! I have gone back to the master file at times to reduce the opacity a bit on the Nik layer if I think it's a piece that might be viewed closer. But up on that wall over the fireplace pretty much avoids pixel-peeping so I think you'll be fine. A couple years ago I was asked for a 30x45, and fortunately the person followed up with "and I want it on canvas for over the couch". I did the happy dance, had it printed at the local lab down in Tempe at 150 dpi and from a few feet back it looked great. Viewing distance and a canvas wrap make for an excellent large print! But even if it's not on canvas, it sounds like viewing distance is on your side. Make a 100dpi 8x10 of a smoother section of the image and pin it up on the wall and see what you see.
Posted by Grant Collier on November 7, 2014 at 4:25 PM
Have you tried up-rezing the image to 200 or 300 dpi before sharpening it? The Preserve Details (enlargement) option in Photoshop CC seems to work well. Also, like Paul said pulling back on the opacity of the sharpen layer can help. I use PhotoKit sharpener and Nik's sharpening is a lot more intense. I think it tends to oversharpen some images at the default settings, so you should be fine with less sharpening.
The good thing is that photographers are usually the only people who pixel-peep. Most people won't notice. I'll warn customers if I think the print size they want is too big for the image and I'll sometimes offer a test print of part of the scene. But I've never had anyone notice any of the slight problems that I notice.
Posted by Grant Collier on November 7, 2014 at 4:43 PM
And you might reduce the viewing distance to "Up to 60 cm." Nik can go a bit crazy with the sharpening if you set it at longer distances.
Posted by Karl Buiter on November 7, 2014 at 5:33 PM
Thanks Paul, Grant.
I do like the ideas about opacity layers (running NIK in PS instead of LR); and/or reducing the viewing distance. While I am generally ok with the 100 DPI print referenced above, another print at 150 DPI needs to be re-run - the cracks on a rock wall look spackled - so yeah, NIK may be a bit aggressive. That said, I have had no issues with 300 DPI sharpening. I just received a Pro-1 that will match the iPF head resolution used by the lab; so I should be able to test some sharpening scenarios before sending the next batch.
On the upsizing question, I NIK-processed and sent files at 100,150, and 300. The lab used 300 across the board - which is a good thing since going back, those lesser DPI sources look worse.
Yep, probably really dot-peeping here. Any issues are mine. The prints all looked damn good.
Posted by Roger Clark on November 8, 2014 at 5:59 PM
Most sharpening methods, including unsharp mask are not actually sharpening. Unsharp mask only increases edge contrast (accutance). Real sharpening is a deconvolution that takes many iterations and a lot of cpu time. I make very large prints (e.g. 4x5 feet) but I will not make a print unless the image will look great even close up, because in my experience, customers will always move in close when they see an amazing image. So I use Richardson-Lucy deconvolution for sharpening as my main true sharpening. See my series on sharpening here:
http://www.clarkvision.com/articles/image-sharpening-intro/
Roger
Posted by Tim Visser on November 8, 2014 at 7:08 PM
Before I consider printing, I always go into Photoshop and see what the largest size I feel comfortable with printing is. Change the ruler size to be exactly 1" as you would see if you place a ruler up on your monitor. Once you have this done, resize the image to the size you want and review. Keep on doing this until you know what is acceptable to you. I have gone away from NIK because of what you are saying. You do not want to over sharpen. I have gone to sharpening within LR as I find it works the best for me at least.
Discussion
6 repliesI have a number of proofs at 300 DPI and 150 DPI when using a Canon Large Format 1200 dpi head. I use NIK Output sharpener set to the correct output and all looks great even up close.
I printed a proof for 100 DPI. At a distance of 4 feet, all looks great. I have some customers that want big; this one 48 x 27", so as long as its going up above the fireplace, sure.... But as I get closer to the print I see all the sharpening artifacts jump right out at me
What I assume is happening is the 300 DPI images, intended to be viewed closer, mix in the eye at a close distance. And the same result occurs for the 100 DPI image at the further 4+ ft distance. I was expecting coarser pixelation; but I am just surprised to see the sharpening artifacts.
So everything is ok?!
The good thing is that photographers are usually the only people who pixel-peep. Most people won't notice. I'll warn customers if I think the print size they want is too big for the image and I'll sometimes offer a test print of part of the scene. But I've never had anyone notice any of the slight problems that I notice.
I do like the ideas about opacity layers (running NIK in PS instead of LR); and/or reducing the viewing distance. While I am generally ok with the 100 DPI print referenced above, another print at 150 DPI needs to be re-run - the cracks on a rock wall look spackled - so yeah, NIK may be a bit aggressive. That said, I have had no issues with 300 DPI sharpening. I just received a Pro-1 that will match the iPF head resolution used by the lab; so I should be able to test some sharpening scenarios before sending the next batch.
On the upsizing question, I NIK-processed and sent files at 100,150, and 300. The lab used 300 across the board - which is a good thing since going back, those lesser DPI sources look worse.
Yep, probably really dot-peeping here. Any issues are mine. The prints all looked damn good.
http://www.clarkvision.com/articles/image-sharpening-intro/
Roger
Tim