You’ve seen them. . . prints from digicams blown up to posters. The pixels are the size of a grapefruit and it’s not pretty.

There are limits to how large you can go. Eventually experience helps you to just “know” these limits, and printer and paper quality play a part in this. But there is a rule of thumb you can use as a starting point.

To calculate (in inches) the largest photo-quality print you can make from a digital file, using its native resolution, meaning no interpolation, divide the vertical and horizontal pixel counts (see your manual) by 240.

If you are making images for commercial publication or other critical applications, or if you want exhibition-quality prints from commercial printers, divide the pixel counts by 300.

Let’s take an image from the Canon PowerShot G6 as an example. It makes a high quality jpeg image at 3072 x 2304 pixels. Using the formula above, that would generate a native print size of 12.8″ x 9.6″ at 240 DPI. Now remember, this assumes you haven’t rezzed up the image in Photoshop.

The next step in the formula is to take this print size and multiply it by 25%. That is the largest amount of image interpolation the picture can stand and still maintain reasonable photo quality – in my opinion.

In the example above, that would change the maximum print size to 16″x 12″.

Note, this is only a GUIDELINE. So don’t make a religion or cult out of my advice. Just use it to get started and do your own experimentation. I think you’ll find that this guideline is pretty accurate.

You can go bigger with some post-processing tricks and add-on software, but the results are far less predictable.

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This post sponsored by the Digital SLR Store

Join the conversation! 26 Comments

  1. I agree with this mostly, I used my digital rebel to print a 16×20 recently, and it was good, but not great. I am wondering though about what you mean with making it 25% bigger? Is there a special way you do this to keep the file looking good, is there a workflow in PS that you do?

  2. Miles what part don’t you agree with? And using your example – your camera will natively yield a
    12.8 x 8.5″ print. If you multiply each of those numbers by 25% you get a maximum size of 16×10.6″. So I am not surprised that your 16×20″ print looked good but not great. It was significantly larger than you should expect to get from your camera.

    There are several different workflows I use – and each is dependent on too many factors to list here. If I am printing for a gallery show – I use one formula – if I am printing on certain papers – I use another.

    Try again using the formula I suggested in the post and see what that gives you.

  3. Yep I agree, 25 % is probably a good limit. I shoot canon’s, and recently went out shooting with my 4×5 the other morning mostly due to my realization that none of my digital images will hang in a gallery that needs 60 inch prints.

    You can see my recent shot here.

    Thanks scott for a great show

  4. Perhaps you mean to multiply the native size by 125%? When you multiply something by 25%, that’s the same as dividing by 4.

  5. Actually I meant multiply by 25% and then move the decimal point – but by 125% would work too. They both end up giving you the same result.

  6. The other factor is the image quality. A good, sharp image can be blown up larger that a slightly soft image. From your perspective as a pro that might seem obvious, but I think it is worth mentioning. And sharpening a soft image isn’t the answer.

    Funny you should mention the G6. I cut my teeth on that camera. Great camera in good light if you aren’t in a hurry. I printed tons of G6 pix at 11×14 and they looked great.

  7. Scott, my inner engineer is making me do this: multiplying 12.8 by 0.25 and moving the decimal point is the same as multiplying by 2.50. That gives an answer of 32, not 16. I think that what you want to say is either: [1] multiply by 125% (1.25), or [2] increase the photo size by 25%. Sorry for being so A-R on this.

  8. Okay Mike Briggs whatever makes you happy.

    Mike I didn’t go into image quality because what I am trying to do is give a general guideline for people to start from. If I wrote a tip that covered every single aspect of getting a great print – it would be 500 pages long :)

  9. [...] Print Size – How big can you go? TWIP Digital Print Size – How big can you go? TWIP: [...]

  10. I think a lot of it has to do with if you’re shooting RAW or not. When I shoot RAW with my Panasonic FZ30 or my Nikon D80 I can get, with appropriate photoshop work, 50″ prints that look stunning. No way I could get anything comparable from a jpg.

  11. Actually Sean in my tests – RAW certainly helps but the formula is generally pretty close for most cases – and again – it’s just a starting point and a guideline.

  12. I have to agree with Sean – I use RAW from my Sony A700 (and using Lightroom) when I need to go big. As a test if I need to go big I take a very small section and print it at the intended dimension on my local printer – its easier than the math.

  13. I see a dangerous trend here – RAW fixes everything – starting to sound like the old “I’ll fix it in Photoshop.”

    Just know that if you plan to go crazy big just because you shot RAW – someday – it will come back to bite you.

  14. Scott, I am wondering if viewing distance is involved in this…Is your formula so that the image can withstand the “Photographer stick your face right up to the print” Test? A pro friend of mine routinely did billboard portraits of real estate agences with a 3 or 4 MP Canon….but of coarse they only look good with a good 500 meter viewing distance lol

    Have you ever tested the program Genuine Fractal? The results from that are suppose to be better then anything Photoshop can do alone……I have never used it (seeing that I never do the poster sized images or anything).

  15. Yes David viewing distance is involved – and I am using the simplest test I know – I have served as a photo editor on several large, four-color coffeetable books. I look at images from that perspective. And again – it’s just a guideline.

    I have used GF and think it probably doubles or even triples the amount of enlargement that you can get away with and still get a good print. I like that it applies the enlargement based on final output, i.e., how big, from how far, under what light, etc.

  16. Scott-

    Thanks man, maybe I will check out GF then…..I think you have started a great topic here for a video tutorial…..The proper way to enlarge an image :)

  17. You guy are trying to push to hard, GF does not work any better than the CS3 resizing options. Average, digital camera images (10-12mp) do not print sharp above 12×18, period, in my opinion. Go to a photo gallery and look at some large format prints, and then come back and tell me what sharp is.

    I went through this in my head for the last year, then I bought all my 4×5 gear back, ONLY FOR SCENES I MAY HAVE PRINTED LARGE. Most of my photos will never be printed above 8×10 anyway, so the rest of my imaging is done with my digital SLR.

    I bring this up because film (large format anyway..not 35mm) is still a VERY useful tool for large prints. Of course I have them drum scanned, and printed digitally.

    I think we all ran away form film to fast, just think of it as a tool in your belt, and not your belt…..

    That is my 2 cents

  18. Like I said…Never used GF before, but from all the reading I have done the algorithm GR uses for interpolation does a better job then anything CS3 has built in……But all of this is 3rd person knowledge.

    I would have to agree that a 12 MP camera is limited to 12×18 if you are going to walk up and stick your noise to the print. But, I still think you can get away with some poster prints if you have a technically well made image and you rez it up properly. When I see a print that large I tend to step back to take the whole image in…..I don’t get right up there to inspect every detail to make sure everything is sharp, just a personal thing I guess.

  19. Man, This is exactly the “rule of thumb” type stuff that I can use.
    Nice job Scott.

    BTW: Your constantly posting of new content is part of the formula for success of this site. Suppling novice to intermediate users relevant material is another. You experts argue the minutia just keep the good stuff coming.

  20. According to my math, using your formula, my D40 6.1MP can produce an image of 11×14 tops but, according to the Scott Kelby Digital Photography Book I can print 13×19 images. Am I doing the math wrong?

  21. Carl this is just a guideline based on my experience. If you prefer Scott’s advice that’s fine. His opinion and mine regarding print quality may be different. I may have more exacting standards than Scott. He’s an author, teacher and entrepreneur first and a photographer second. I am a photographer first so I may have stricter standards.

    In the end – trust your own eyes. If you like the 13×19 quality you get go for it.

  22. Scott, this may be an excellent topic for the next episode. Print sizes, and Does film (obviously not 35mm) still have a use?

  23. Scott and everyone

    I recommend a page by Thom Hogan which discusses this issue. http://www.bythom.com/printsizes.htm

    He generally agrees (I think) with Scott, but breaks it down by dividing print sizes for different starting resolutions into Excellent, Good and Poor quality. Basicaly, he says that 10 or 12MP can do solid ‘Good’ quality at 11×14, and borderline good quality at 13×19.

    He is a bit more generous with the ability to ‘upres’ (200% rather than 125%), but he also says that doing so depends on an excellent starting image, including sharpness through shot discipline and proper sharpenning and other factors.

  24. If anyone is interested in seeing some 50″ prints from a digital point and shoot, I have 2 gallery openings in Toronto in May that include such shots (and also ones from my Nikon D80). Drop me a note and I’ll happily provide you the coordinates.

  25. Scott, As an offset printer I can say your formula is the one we have been using for years. While we can print an “acceptable” image at 150DPI We always stress that we want an image that is 300DPI AT SIZE. That means if you want me to crop 50% of the image and then enlarge in to 5X7 to fill out your newsletter you had better give me a lot of data. The rule I was always taught in our type of printing is that an image should be 2X Line screen (We print at 150 LPI). As with all prepress rules. Talk to your printer and they will guide you.

    Ray

  26. [...] example this entry on print size is a nice example of good advice you can get on the [...]

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Founder of Photofocus.com. Retired traveling and unhooking from the Internet.

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