Posted by Nathan Buck on November 16, 2014 at 2:23 AM
Hi all.
I have an image that I need to up-res, and I was wondering if I could get some suggestions on how to best go about up-resing.
I have a 10.2 MP image from a Nikon D80. I would like to get the image to somewhere around 20X24 if possible.
Do you happen to have any suggestions on how to best up-res and sharpen for printing much larger.
Thanks in advance.
Nathan
Posted by Keith Bauer on November 16, 2014 at 9:14 AM
Nathan:
You should strive to get a file that is at least 240 ppi for printing. 300 ppi would be better but 240 will suffice. That means you need to up-res your image to 4800x5760 @ 240 or 6000x7200 @ 300.
Assuming you have Photoshop, simply open the Image / Image Size dialog box type in those dimensions. (You can do it in inches or pixels). Just make sure your resolution is set to the desired amount.
You can do this in one process. In historical days, it was better to do the up-res in 10% increments. That is no longer necessary with the algorithms in Photoshop.
If the image is very sharp to start with, you should be able to pull this off. You will most certainly need to apply sharpening the the final print sized image for best printing quality and display. Sharpening will be a matter of specifics for the image.
Nathan, for the same purpose I too increase the size in steps of 10% with Bicubica softer. I often tried different ways but always came back to this solution. After I sharpen with Focal Blade that allows a good control of noise, delicate surfaces and high lights. Then in a different level I add an action for sharpening the edges only. At last I modulate both levels with Opacity according to the characteristic of the photo. In many images a plug-in against noise is needed, often only color noise, at least in the softer areas.
I hope it helps.
Take care.
Posted by Roger Clark on November 17, 2014 at 10:06 PM
Hello Nathan,
"Up rezzing" to make a larger print needs to have few artifacts and good sharpening methods post "up rezzing." Best to use a relatively simple method like cubic spline (definitely no cubic sharper which will introduce ringing artifacts). Whether doing it in increments or all at once is largely irrelevant in my opinion and tests. One simple increase works just fine. Once "up rezzed" the sharpening methods makes all the difference. Note that the typical methods in most image processing systems. like unsharp mask in photoshop, do not actually sharpen. Unsharp mask enhances edge contrast (accutance) which gives the illusion of sharpness but in many cases, actually reduces sharpness. I use Richardson-Lucy deconvolution and find in a typical high signal-to-noise digital image, resolution can be approximately doubled (thus a 20 megapixel image becomes an 80 megapixel image). Details can be found in my series on sharpening:
http://www.clarkvision.com/articles/image-sharpening-intro/
Discussion
3 repliesI have an image that I need to up-res, and I was wondering if I could get some suggestions on how to best go about up-resing.
I have a 10.2 MP image from a Nikon D80. I would like to get the image to somewhere around 20X24 if possible.
Do you happen to have any suggestions on how to best up-res and sharpen for printing much larger.
Thanks in advance.
Nathan
You should strive to get a file that is at least 240 ppi for printing. 300 ppi would be better but 240 will suffice. That means you need to up-res your image to 4800x5760 @ 240 or 6000x7200 @ 300.
Assuming you have Photoshop, simply open the Image / Image Size dialog box type in those dimensions. (You can do it in inches or pixels). Just make sure your resolution is set to the desired amount.
You can do this in one process. In historical days, it was better to do the up-res in 10% increments. That is no longer necessary with the algorithms in Photoshop.
If the image is very sharp to start with, you should be able to pull this off. You will most certainly need to apply sharpening the the final print sized image for best printing quality and display. Sharpening will be a matter of specifics for the image.
I hope it helps.
Take care.
"Up rezzing" to make a larger print needs to have few artifacts and good sharpening methods post "up rezzing." Best to use a relatively simple method like cubic spline (definitely no cubic sharper which will introduce ringing artifacts). Whether doing it in increments or all at once is largely irrelevant in my opinion and tests. One simple increase works just fine. Once "up rezzed" the sharpening methods makes all the difference. Note that the typical methods in most image processing systems. like unsharp mask in photoshop, do not actually sharpen. Unsharp mask enhances edge contrast (accutance) which gives the illusion of sharpness but in many cases, actually reduces sharpness. I use Richardson-Lucy deconvolution and find in a typical high signal-to-noise digital image, resolution can be approximately doubled (thus a 20 megapixel image becomes an 80 megapixel image). Details can be found in my series on sharpening:
http://www.clarkvision.com/articles/image-sharpening-intro/
Roger