What's "good enough" resolution/DPI for a 14x10 print?

[Mike Lee]

I'd like to print a photo of a juvenile bald eagle that I took. The print company has a 14.4x10.8" size that I'd like to use. Unfortunately, the image I'm thinking of printing is from my 10 megapixel Rebel, so printing at that size would put the print at 240 dpi, lower than their recommended 300 dpi. I've never done a print like this before, and I'm not sure how important the difference between 240 and 300 dpi will be once it's up on the wall. I don't imagine that people will start pixel peeping the shot on the wall, and the large size will make it stand out better in the room, but it's a bit of a shame to not fully utilize their full 300dpi resolution. If you were in my shoes, would you print at their smaller 9.6x7.2" size for ultimate sharpness, or go for the bigger size to optimize for across-the-room viewing? Thanks!

[Diane Miller]

Use your image editor to upres it to 300 at the desired size and inspect the result at 100%. Most images will upres very nicely at that amount, with proper control of sharpening.

[Mike Lee]

Good idea! Not sure why I didn't think of that, but I'm quite the newbie. Thanks!

[arash_hazeghi]

Hi Mike,

It won't make much of a difference because when you up-sample your photo you are not adding any extra detail or information to the file. Up sizing a photo and printing at 300 dpi vs. native size at 240dpi will not make any visual difference eve upon close inspection. In this case you will just increase your file size

If you are concerned with "dithering" in prints it won't happen when using a serious printer such as Epson or Canon pro models. They will internally interpolate the data and print at much higher actual DPI (4000-5000 dpi on select papers).

best

[Mike Lee]

Hi Arash, thanks for the thoughts. I think what Diane meant, and what I'm thinking, is that enlargement would let me see how the loss of resolution might look. I know that it's not a movie magic "enhance" function that adds detail.

My intent is not to advertise for other sites, but since it might be relevant to the discussion, it's a site called Fracture that prints directly onto glass. Hopefully you aren't all shaking your heads at me being taken in by a fad, but I'm interested in trying it out. For this printing process in particular, I'm not sure what they're doing when enlarging images to print at larger sizes, and if it's a 1000+ dpi process like you mention. In the absence of more information about what they do, could manually controlling the enlargement improve the result over an automated process? Or if it's all a wash, I can save a step and send them my 240dpi image.

[arash_hazeghi]

Hi Mike, what I said was for inkjet fine art printing, I don't have any experience in printing on glass. I'm sure you can ask them for some test prints

best

[Don Lacy]

If printing on glass is like printing on aluminum prepare the file as you would for a inkjet print that includes sharpening I would call to verify then prepare the file to meet their recommendations. I prefer to send a properly sized and sharpen file to my lab over letting them do it.

[Diane Miller]

Don's approach is what I would do. Any automatic up-res the printer would do (from your 240 to their recommended 300) is probably as good as your doing it yourself, but I'd want to have a look to see if I wanted any additional sharpening, for example. In any printing process, no matter what the substrate, some sort of proprietary resampling will occur if the file isn't already at the optimal size. For inkjet printing, the magic number has always been debated and is apparently a trade secret for each printer, although 360 dpi has been the usual guess. On most substrates a little resampling by the printer driver won't be noticeable, such as from 240 to whatever is actually optimal for the printer) but I like to see the closest approximation I can get.

Upsampling changes the number of pixels in an image by interpolation. Adding extra pixels can soften an image unless some sharpening occurs to counter it. When you resize with a resample in PS you have several choices of the algorithm (one of the four bicubic choices are usually the best) and I'd want to try them and make my own decision which is best rather than leave it to a printer driver or RIP.

[Grady Weed]

...and I'd want to try them and make my own decision which is best rather than leave it to a printer driver or RIP.

I agree with Diane!!!

[Jonathan Ashton]

I use Epson Pro 3880 and I leave it to the driver to sort out. So long as the print is about 180dpi or higher it will be fine.

[Mike Lee]

Is the 180dpi based on the size of the print and the expected viewing distance? Ultimately what I'm trying to get a handle on is what is good enough for certain situations. This article has been cited on these forums before:

http://www.clarkvision.com/articles/printer-ppi/index.html

which has some really high numbers for what an eye can resolve, but I imagine that's under ideal circumstances that might not be required for large prints seen at longer distances. (I should really read the article all the way through; I've only skimmed a few times.)

[Don Lacy]

Mike if the image has not been cropped then 10 MP is more then enough for a 11 x14 print, I have made prints as large as 16x20 from a 10 mp camera.

[Mike Lee]

Thanks! I know that this will get more familiar with time and experience, but I wanted a basic understanding of what to expect and what to shoot for.

[Jonathan Ashton]

Is the 180dpi based on the size of the print and the expected viewing distance? Ultimately what I'm trying to get a handle on is what is good enough for certain situations. This article has been cited on these forums before:

http://www.clarkvision.com/articles/printer-ppi/index.html

which has some really high numbers for what an eye can resolve, but I imagine that's under ideal circumstances that might not be required for large prints seen at longer distances. (I should really read the article all the way through; I've only skimmed a few times.)
The 180 dpi suggestion is based purely on subjective analysis.
My pal produced a number of A3 prints for Epson lecture they were printed at various resolutions and to all intent and purposes 180 dpi was about best acceptable minimum, people were guessing which was 180 240 and 300 and 360, once prints fell below 180 it began to show in some prints.

[Don Lacy]

The 180 dpi suggestion is based purely on subjective analysis.
My pal produced a number of A3 prints for Epson lecture they were printed at various resolutions and to all intent and purposes 180 dpi was about best acceptable minimum, people were guessing which was 180 240 and 300 and 360, once prints fell below 180 it began to show in some prints.
I just did a 20X30 metal print that I did not want to resize so I sent the file in at 200 dpi and the print is stunning

[Jonathan Ashton]

There you go Bob's your uncle:S3:

[William Giokas]

In the wild with your eye you don't see at 300dpi! It will be fine and your only talking 40 points. The problem that I see on this Forum is people tend to over sharpen their images.Bill