Resize and sharpening settings for poster sized canvas prints

[Rudi van den Heever]

I am looking for some sound advice on how to sharpen for canvas printing after having enlarged images to sizes A0, A1 and A2.



I found this guide on the net http://www.cambridgeincolour.com/tut...sharpening.htm ,but it does not solve my problem as it does not specifically deal with enlarged canvas prints.



I do some input sharpening on my RAW images in Lightroom 3 and then the output sharpening in CS5. I have read Scott Kelby's suggestion of a double luminosity unsharp mask at 120%, radius 1 and threshold 3, but really do not want to fool around with test prints on today's prices!



Does somebody have some rule of thumb settings to give me a head start on sharpening for canvas prints of the mentioned sizes, or should I simply do the output sharpening in Lightroom 3(sharpen for matt print, high) and leave the rest (enlargement AND the sharpening thereafter) to the lab?



If necessary, the answer to the question whether I should enlarge with bicubic or bicubic smoother in the Image Size box, will also be appreciated...

[Roger Clark]

Hi Rudy,

In my opinion, sharpening is image dependent, so there is no single magic formula.

I suggest reading the "Important Sharpening Information" in the educational resources:
http://www.birdphotographers.net/for...read.php/18534

I personally would try enlarging with bicubic, look at the results and if artifacts are seen, use bicubic smoother. Then I would sharpen with Richardson-Lucy image deconvolution. I would not leave it up to the printer.

Roger

[Tom Graham]

Canvas printing. Haven't tried that. Think it would be very dependent on canvas used?? For starters, I might try making up a composite print of the same image at different sharpening settings. That is, print the same 4x5 inch (piece of) image 6 times, each with different test settings, with all 6 on the same single sheet of canvas. (Be sure and put/print ID on each image).
Tom

[Dan Osman]

Canvas printing. Haven't tried that. Think it would be very dependent on canvas used?? For starters, I might try making up a composite print of the same image at different sharpening settings. That is, print the same 4x5 inch (piece of) image 6 times, each with different test settings, with all 6 on the same single sheet of canvas. (Be sure and put/print ID on each image).
Tom

Yeah I agree.