How big can I expect to be able to print out this image?

Factual Questions
1

Image info (please tell me if there are numbers I’ve left out):

size: 3056 px x 2292 px
resolution: 480 dpi x 480 dpi
bit depth: 24
color: sRBG

I was near my alma mater on Sunday with my camera and my tripod, so I stopped by to take some pictures. A couple I’m particularly proud of and am considering getting professionally printed and framed to put up in my home.

What’s the largest I could expect to be able to print out an image with the stats above and expect it to look, you know, like a photo?

For extra credit, please show your work.

2

Im sure you could downres it to 300 and still look great- a normal print would be 10 inches wide at that resolution. Some applications out there are getting very good at blowing up digital images and keeping a natural look. You could probably get a really nice print 20 inches wide. Depending on your standards- Im sure you could get a print 5 feet wide that looks fine too from a little more of a distance

3

You shouldn’t have any trouble getting it up to 11x14 or even 16x20. The larger size might look a bit grainy, particularly if the original was shot at a high ISO, but unless people are examining it with a jeweler’s loupe, they’re not likely to notice.

Note that dpi doesn’t seem relevant in your OP as dpi only comes into play while printing. Generally, you don’t need to go above 250 - 300 dpi, but lower can be acceptable depending on your personal preferences.

So if you have a 3056 pixel image and want to print it at 20 inches wide, you’ll get 150 dpi. That’s enough for a fair to good image. Make it 200 dpi and you can have a 15" image (essentially 11x14).

But…it all depends on your original. If you’ve compressed the image with severe jpeg compression or took the picture under sub-optimal lighting conditions so that the shadow areas are grainy or show chromatic noise, then a larger print may reveal the flaws.

4

I agree. You’ve got a 6 MP image there. With a little up-sampling, you can easily print up to these sizes, provided you’ve got a good file to start with. I have many old pictures from a 6MP camera that I’ve blown up to 13"x19" and they look fine. You can see a little loss in quality if you look very close, but at normal viewing distances, it’s more than adequate.

5

Well, if you mount your picture over on the other side of the galaxy, I expect that a couple of parsecs per pixel would give you a decent photo-like view from earth. Those dimensions’d be about 19,900 X 14,900 light years.

IOW, how far away are you going to look at it from?
It’s the angular size of the pixels that determine whether something looks like a photograph.

6

Correction. 7 MP.

7

In general, print requires between 200 and 300 dpi. At 300 dpi, that would be about an 8x10. The resolution dpi that is listing in the file is not useful information, the only thing you really need is the number of pixels.

8

If you are printing on a textured surface (like canvas) you can go to as much as 5’x3’.
A print this size isn’t designed for close viewing, but will look great framed and hung over a fireplace.

(5’ = 60", 3000 pixels/60" = 50 pixels/inch
The commonly stated resolving power for the human eye with 20/20 vision is 1/60 degree of arc. At 5’, 1/60 degree is .01745 inches, or 1/57 of an inch. Therefore, a 50 ppi print will be almost perfectly resolved when viewed at 5’).

9

Thanks for the info, all. The metadata on the image says the ISO is 80. I don’t know if that’s high.

FWIW, if it matters at all, here’s the original image and here’s my cropped and retouched version, which I deliberately stored more compressed because I was emailing it to someone. It’s not my final draft.

Once the image is pulled from the camera and saved as a JPEG, what’s the best thing I can do to preserve the quality of the image through cropping and retouching? Given that it’s been compressed once, am I right in thinking that converting it to a lossless format at that point (before cropping/retouching) will at least preserve what I’ve got, or is it pointless by then?

10

There’s a good bit of JPEG artifacting there, and some ugly magenta-green chroma noise in the shadows by the trees, but I don’t think it will be that noticeable in a print. I’m assuming this was taken with a compact point-and-shoot or something similar? As mentioned above, with a canvas print you can get away with quite a bit. For a regular print, I probably wouldn’t print it much bigger than 14" across. But you might be able to get away with 20" or more. It all depends on the viewing distance. As for upsampling this, it’s going to be a rough one to upsample, as the pixels that are there are not the cleanest or clearest.

Yes, save in PSD or TIFF (LZW compression is what I use) or whatever your preferred format is once you’re ready to save your first draft. What you generally don’t want to do is JPEG something that has already been JPEGed. JPEGging a JPEG once isn’t that big a deal, but if you keep coming back to it and resaving it each time, you’ll definitely notice image degredation.

11

You have to also include “viewing distance”.

Acceptable resolution for a large billboard visible from a street intersection is different from a photo held at arms length.

12

Thanks again to everybody.

Yes, I took this picture with a little point & shoot.

I think I’ll see what size options I have for printing and maybe (if the price is right) just go for a variety of sizes from, say 14" across to 24" and just frame the one that looks best. :slight_smile:

13

For info, iso 80 is very low, and as low as it will go for most cameras. Which is good in your case, since low iso means less grain !

However, the compression didn’t seem amazing in here. You may want to look if the image quality (i.e. compression quality) was set to maximum, and if no you should consider increasing it.

14

The “sharpness” quality of a photo is not just the number of pixels.
The amount of detail captured is also dependent on the quality of the optics in the camera as well as things like motion artifact.

I think it’s reasonably easy to approximate what your photo (nice photo, btw) would look like if enlarged by simply opening up the file with a high-quality monitor and then further enlarging it to the size you want…

As an example, my (fairly inexpensive) regular computer monitor is 27" diagonally and has a native resolution of 1920x1080. You could take your file, display it on the monitor, and keep enlarging it until you decided it wasn’t worth enlarging further for the viewing distance you propose. Obviously at some point larger than the size of the monitor, you’ll only be looking at a portion of the photo, but you can still get a pretty good idea of what kind of (sharpness" (resolution) you’ll get at size x.

It’s my personal opinion that “megapixels” is not a super terrifical way to decide how much you can enlarge a photo, even though it’s an approximate parallel and even though in the early days of digital photography there were some good rules of thumb back when a megapixel or two was a big deal. Not only the quality of the pick-up chip and processing play into the final result; so do the optics and motion and lighting level, and so on, once you get past a few megapixels of resolution.

15

I totally agree. I have a 13"x19" portrait of Stud Terkel in my home office right now that a friend took with a 2.7 megapixel Nikon D1 (Nikon’s first-generation dSLR.) The print looks great at that size, despite the (relatively) low pixel count. It’s not only how many pixels you’ve got, it’s how good those pixels are, which is dependent on various factors, including optics, noise characteristics of the sensor, per pixel sharpness, etc.

16

Thanks!

17

It really depends on the image quality for printing. This picture of our chief is the large version original and this photo reduced size from the original. If you are enlarging a small picture you loose quality and it pixilates. Meaning that the picture will look very blurring if you enlarge it from a small picture.
If you do it the other way from large original to small you will always retain the quality.
Good luck and I recommend a free site photobucket where you can do all kinds of editing and see the results immediately.

18

Costco charges about $3.99 in my neck of the woods for a 12x18 IIRC; for that it’s worth experimenting. get a print made of the full pic, get a print made of the center cropped to half size (say the tower) so that if you printed the whole thing at that enlargement it would be 18x30 or something. That should give you an idea. Experiment trumps theory.

Many photo printers work their own magic on the image so you get a smoth picture, not a pixilated bunch of squares like the monitor may show in blown-up view. They want to help you and get repeat business. I have a Fuji 4900Z image, 2.4MP interpolated by the Fuji to 4MP and printed 11x14 and it’s a bit grainy but very nice and pretty sharp. I suspect most limitations nowadays are the lens quality of the smaller P&S camera, not the sensor or JPG artifacts.

As others point out - it depends on how far away you are looking at the picture from. For magazines, from 12 to 18 inches away, 300 to 400dpi (dots or pixels, details, details…) is good. For regular photos on a wall, 100dpi to 150dpi full colour is good. For posters to admire from 3 feet away, 50DPI might work. YMMV.

Blow it up in your monitor so the picture is 3 monitor-screens wide; that’s about 3 feet by 2 feet or so; and since your monitor is probably 1 foor horizontal and 1280 pixels, that’s about 100dpi.

Every time you re-save a JPG you lose a little bit of information. This is not a big deal if you edit your original JPG, crop it, and then save as a second JPG. It is if you are going to edit, make a few changes, save. Come back each day for a few weeks and open the work in progress, tweak it some more, then save as JPG again. Even worse if you crop or something to change the boundaries of the 8x8pixel tiles that JPG works with. If you must do this, store everything between the original and the final product as lossless like photoshop PSD or TIFF.

NEVER NEVER OVERWRITE THE ORIGINAL CAMERA IMAGE. Treat this as we used to treat the negative in film. It is your best starting point for every new attempt to crop, edit, enhance etc.

If you really want to enhance resolution - you can’t do those stupid tricks like CSI and the movies do, where they blow up a pixel into a recognizable face; you can, however, use programs like (IIIRC) Fractal Magic to enhance the sharpness of an existing picture so you can resize it as say, 10MP or 12MP.

19

Nice photo. Although this is not what you are asking, I will suggest that your crop include the top of the tree. Just MHO.