5184 X 3456 Print Size

[Prospero Barela]

FWIWdpi (dots per inch - only applicable to inkjet, laserjet or half-tone printers) isn't the same as pixels-per-inch (ppi). It takes at least four such colour printer dots to represent a single pixel.

For digital use (websites etc.) you can completely disregard dpi/ppi. They have no meaning. Instead you just need to look at the screen resolution/dimensions at which your photos will be displayed (shop, purchaser) on-screen and adjust your photo dimensions accordingly. The current 'High Definition Resolution norm' is 1920 by 1080 pixels. As screens gradually increase in resolution you may need to increase your photo dimensions to display the best 'High Definition' Resolution.

Printing pictures is a whole other territory. The standard photo-printing resolution is 300 dpi. A High-Resolution print (magazines, etc.) may even be 600 dpi. So if you know the size of the print and the print-resolution, you can work out how many pixels you need to deliver in order to make a print at that resolution quality. If you send me a PM with your email address, I can send you an Excel worksheet which you can use as a template.

You can advertise the image as 5184x3456 pixels with 72dpi. It doesn't matter. If the person wanted to make a 17 x 11.5 inch print he would just print it at 300 ppi. or what ever ppi he chose to make a given size print.

The correct terminology is ppi not dpi. You are dealing with pixels not dots. Since a small pixel looks like a dot ignorant people started to call it a dot. If you are talking about how many dots per inch a printer spits out then that is it dots per inch.

All of these calculations of print size are misleading and wrong. Your image can be printed at multiple sizes. If the exported photo is 4000x6000 pixels, you can print it 8x12 in which case it prints at 500 pixels per inch, or you can print it at 4x6 inches which would be 1000 pixels per inch, or you can print it at 10x15 in which case it would be 400 pixels per inch, or you can print it at other sizes (regardless of the number you specify in the export dialog box).

If you are going to print at just about any size (except for extremely large print sizes), you UNcheck the box that says "Resize to Fit", and you get maximum resolution, which produces maximum quality.

If I export this image with a resolution of 72 pixels per inch , the print size is 72 * 48 Inches - I think this is the maximum size which can be extracted from this (Simililar to JPEG) . . .Am I right ?

If I shot in JPEG mode (that is 72 pixels per inch ) and I am exporting from LR "300 pixels per inch" . . .will this image reconstruct the pixels from 72ppi to 300ppi ? (or is it digitally reconstructing the image?) will it loose or gain quality ?

The resolution of your file is based on the number of pixels in the original Raw file, in you case 5184 x 3456. When you export a file, these pixels almost always need to be either reduced in number or increased, depending on the size and output resolution of the you specify in the export dialog. For example, you choose 8 x 12 inches for your print, and you specify 240 pixels per inch (ppi) the resulting file would have now have 2880 x1920. This is called resampling.

Lightroom does this automatically when you use the print module, and print to your own printer. If you are giving the file to another person to print, then you need to know the optimal ppi needed by that printer as well as the print size. Lightroom will resample the image to give you perfect results.

I work as a professional printer, and can tell with a certain degree of confidence, that this is quite flexible. Files export from your 60d as 14.4 x 21.6 inches if you do not resize them, this is the native resolution of your camera with an output resolution of 240 ppi. However, you will achieve great results exporting as large as 20 x 30 inches as long as the image is sharp and well exposed. Lightroom can upsample your files with little appreciable visible loss of image quality as long as you don't go more than twice the native resolution. For most inkjet printers, 240 ppi is a great output resolution.

The best export for printing is the UNcheck "Resize to Fit". This requires no change to your pixels, every single pixel in your photo is exported, 1-for-1, pixels do not have to be invented or interpolated or made up.

I am sorry dj_paige, you give great advice on many Lightroom subjects, but on the print process you are incorrect. Lightroom always resamples an image if you choose to resize on export. Lighroom always resamples an image when you send a file to a printer from the print module.

Printers use a specific screening resolution in order to create an image using the ink set of that system, or the optical properties of a continuous tone printer. If you don not resample when you export a file to be printed at 6x4 inches, then the print driver will resample it instead. A printer can't use a resolution of 864 ppi. There is no way foe the printer to create accurate color if there are not enough ink droplets to reproduce the color of a pixel.

Here is an example: A specific printer has a resolution of 2880 dpi (drops of ink per inch.) You send a file that is 864 ppi to the printer. The printer can only use 3 drops of ink per pixel (2880 / 864 = 3.3) The printer has 4 colors of ink Cyan, Yellow Magenta and Black. You are printing an image of a forrest. There is no green ink in most printers, so it will use both yellow and cyan to reproduce a green color. The printer can use 1 drop of yellow, 1 or 2 drops of cyan, that does not give you many shades of green, in fact you get 3. That is not enough variety to reproduce the colors needed in the image.

The bottom line is you need to ask the person printing your images what to correct output resolution is for their print system. Most ink jet printers work great with 240 ppi (that is why it is a default value in Lightroom.) Other printing systems may use 300 ppi.

No that's not what I said. I said ... paraphrasing ... the meaningless calculations done in the software decreases when you increase the resolution. The print size does not change. Your 5184*3456 photo can be printed at any size you want. Your photo can be printed a 6x4, which is 864 pixels per inch; or the exact same photo can be printed at 12x8, which is 432 pixels per inch, and it can be printed at any other size you want ... regardless of the resolution number you select when you export and regardless of the number of inches in this meaningless calculation in your software. The pixels remain the same, not a pixel changes when you change the meaningless resolution number, and so you have the exact same photo, regardless of what the resolution number is.

JPG mode is not 72 pixels per inch, there is no such thing as inches for digital photos (only for printed photos). Your third question: when you export with "resize to Fit" UNchecked, if you had 5184x3456 pixels before the export, you get 5184x3456 after the export.

For most printers 300 ppi (Epson printers 360 ppi) is the "optimum resolution" to obtain maximum print detail when viewed at close distance. This would include any prints or print albums viewed handheld, such as 4" x 6" up to 8" x 12".

The actual image file ppi can be much lower depending on the "viewing distance." Photo enlargements that will be hung on a wall and viewed at a distance of about five feet require 115 ppi resolution image files. For your Canon 60D image files (5184 x 3456) you could print up to a 45" x 30" enlargement and still have a print that would look good at a "normal" viewing distance. People view paintings and large prints at a distance where they can see the whole image. ERGO: The larger the print the greater the viewing distance. There are of course exceptions such as aerial surveillance photos, but that's a whole different subject matter!

My first DSLR was a 6 Megapixel Canon 300D with 18-5mm kit lens. 16" x 24" prints made from its 3072 x 2048 (128 ppi) raw image files are sharp when viewed as close as three feet. The camera JPEG files wouldn't fare quite as well at this size of enlargement.

For 11" x 17" and larger prints use the full-size 5184 x 3456 Output file (i.e. no Resize). Most printers do a very good job of upscaling the image file if required and applying the appropriate Output Sharpening for the target paper. For smaller prints you can resize the images to 300 ppi (Epson printer 360 ppi) to reduce the file size and apply the appropriate Output Sharpening (Glossy, Matte) to insure good results.

I like your answer but want to clarify something. My current Light Room Image Sizing is: Resize To Fit box is unchecked and in the Resolution box I have 500 pixels per inch. Is this good for just about any size including 8"x12"?

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