digital size equals print size?

[skip_converse]

Being rather new to digital imaging, I am puzzled as to what relation the digital

1080x650 converts to print size. What is that relation? I hope my question is

stated adequately for an answer.

 

Warm regards,

Glen

[remco-jan.woldhuis]

For printing you should calculate with 240..300 dpi (dots per inch), depending of the

print size (for large prints you can work with 200 or even 150 dpi.

 

So in your example, 1080x650 pixels can be printed at approx. 3.5 x 2 inches.

[kurt_evers]

There is no absolute, definitive answer to your question. The resolution you mention is quite low. The larger you print your image, the worse it will look. So maybe the most meaningful answer to "How large to print?" is, "As small as you can tolerate."

[skip_converse]

Perhaps I did not state my question correctly due to my own confusion. Better stated: How do I know the size of my picture/print based on the numbers given on my camera for size?

[tonybynum]

the standard for small prints is 250-300 dots per inch. take the 1080 by 650 (the size you said your files are) and divide each by 300 dots per inch (the standard for printing small prints) 1080\300 dpi = 3.6" x 2.2" print, if you use 250 dpi and divide 1080\250 dpi = 4.3" x 2.6" image. very small. . .

[Matt Laur]

Skip: there is a "why" component to this that's not being mentioned, here. When a device (lab equipment, or your own inkjet printer) renders a print, it's having to take the individual pixels (picture elements) that are captured by the sensitive grid of photosites on your camera's sensor, and turn those into a corresponding grid of printed pixels on the paper. If those printed pixels are small enough, and close together enough, the human eye will see them as a smooth continuum. As a general rule of thumb, a print that has 300 of those pixels crammed into a given linear inch will look pretty good to most people, even on close inspection at normal (say, reading) distances.

 

As a point of comparison, your computer display is showing you somewhere between 70 and 100 pixels per inch of display. So, an image that's recorded with 1080 pixels on the long side will would come close to filling up a computer display that's 1200 or so pixels wide (not an unusual dimension these days). But when printed at 300 pixels per inch on paper, you get only a few inches of quality output, as mentioned above. You CAN print it any size you want, but at some point, as the print gets larger, you'll be able to too-easily discern the individual pixels recorded by the camera.

 

There are software tools that can help enlarge an image file, creating a file with more pixels, and using some tricks to smooth things out, or even to add artificial texture to help. But it's hard to fool the human eye when you're starting out with too-small of an image in the first place.

[lyle_aldridge1]

Same as above. There is no "set" ratio of pixels to inches, so "equal" can't be computed. But most would divide the pixel dimension by about 200 to 300, or even 360. The precise number is mostly a matter of your personal tolerance - how densely your eyes need the pixels to be packed to make the image seem acceptable. It's also affected by the quality of the image file and of the printer. Many people find that 150-180 pixels per inch produces an "acceptable" print on most printers, but those people don't tend to hang out at Photonet. I suspect that most around here use about 200- 240ppi as their minimum acceptable "rule-of-thumb" value, but even that is subject to up and down adjustment. All pixels and printers are not equal.

 

What you may be asking, though, is how large a print your software will produce by default. You'll have to check your software for that. Many will default to 72ppi, which is an older monitor spec. If you print that that setting, you won't like the results, but you can adjust that in your software.

[Ed_Ingold]

Skip

 

As a beginner, you may not know that the size and resolution are arbitrary but related values. The true "size" of the image is the number of pixels. For any dimension, length or width, the following relationship holds --

 

Pixels = length (inches) x resolution (pixels/inch)

 

If you change any two values, the third value is fixed.

 

Many P&S images default to 72 ppi (pixels/inch), often at a large physical size in inches. If you re-dimension the image WITHOUT RESAMPLING only the print size is changed without any damage to the image itself because the number of pixels is unchanged. If you resize AND resample, the number of pixels are changed forever.

[r_johnston]

You probably know this, but just to be safe, never work on an ORIGINAL image in JPG, Save a copy as a TIFF file and experiment with it.

 

First we see nowhere have you specified the "resolution" of the file. Resolution in PIXELS PER INCH and Print size in DOTS PER INCH are two different topics. most are assuming your resolution. Only by knowing it exactly can a file size in inches be determined.

 

If your camera makes photos at 300 pixels per inch, you can make bigger prints, even if the file size in inches is small.. Some cameras record the image at 300 PPI, some much ... less, have seen some toy cameras at 52 PPI, there may be some even smaller..

 

Photoshop will show a 1080x650 pixel file that has a resolution of 300 pixels per inch, as a file which is 4.6" x 2.167" If you change the resolution to 250 ppi, the pixel WIDTH OR SIZE of the file in PIXELS will be smaller, but the size in INCHES will not change. You lose resolution or sharpness and possibly detail. THIS may not be apparent on your screen, which DISPLAYS the image at 72 pixels per inch.. Because it looks JUST as sharp, some think it will print as sharp.

 

Now, as for printing, that is another ball of wax, you can set printing size, to your choice in PRINTING SETTINGS, try it at the original size.

Then, Print one as a 4x6, 5x7, 8x10, 11x14, not changing the file size, but the PRINTING SIZE in PRINTING settings....

 

The only way to really learn this, is to make prints of varying size to see how they look to you. What I require as a quality print can differ from what you feel is a good print.

 

If you set it to print using 300 DOTS PER INCH, it will look good. If you increase the size for printing in the software, and use a higher DOT PER INCH, like 1200 or 2400, or 4800 it can have more saturation and also make a larger print, which may be acceptable to you. It can also depend on the media, paper, canvas, etc. I never print on canvas with less than 1200 dots per inch.

 

Many times people are confused about PIXELS PER INCH, and DOTS PER INCH.... Many times people say there is ...no... difference, that is only if they do not know the difference or are confused. These are ....not... interchangeable terms, dispite those who keep claiming they are.

 

PPI is the Resolution of the digital Image.

Pixels are much larger than DOTS.

Dots per inch, is how many dots of ink or dye are sprayed by the printer, on one inch of paper. The dots are much smaller than a pixel, if we sprayed pixels, prints would be much coarser or have blobs of ink..

 

If your printer will print with 1200 or 2400, and 4800 dots per inch like mine, there must be a reason the manufacturer made it that way. Higher DPI produces better prints.

 

Experiment with it to see what you like or how much better prints look. 300 DPI is what most use, unless you tel them differently. If you see a National Geographic magazine, the pictures look much better than most photography magazines. They do not print at 300 dpi, so their magazine pictures look much better..

 

Why do most print at 300 DPI, it saves them a lot of ink or dye, and others because they do not know how much better they can be.. On my printer, I use more ink, but to me, the difference is well worth it, especially when I am making large prints.

 

Try it, and decide for yourself..

[kelly_flanigan1]

A ballpark rule of thumb is pixels per mm in printing is about equal to the pairs of shoes per woman.