What determines the size of your print?

[Yisehaq]

Hey all,
I just wanted to ask what determines the size of a print? Is there any rationale to follow when you think of printing your photos?
cheers,

[Marko]

Indeed there is. First thing to check is the size of the FILE.
Open it up in a graphics program and somewhere it should tell you how big it is in pixels (for the web) AND how big it is in inches or centimeters (printing size)

Of course this is 100% related to the QUALITY of the capture. Ie a RAW file will capture more info than a jpeg. Thus it's filesize will be larger, thus you can print it larger.

Another thing to be aware of is WHO will print the image. If it's you, no worries. But if it's a lab, they may well have a format that they print in. If your cropping is non-standard, they may want to charge you more, convert the image to a standard size, say no we can't do this like this, etc.

Hope that helps - Marko

[Iguanasan]

The size of the print is really determined by math. Probably didn't want to hear that, eh? Take, for example, the full size original of this print, , it's 3690 x 2493. Computer monitors are generally about 72dpi (dots per inch). So, 3690 / 72 = 51.25 inches and 2493 / 72 = 34.625 inches or about 50 x 32 on a monitor. Now, let's take a look at actually printing it. Your average laser printer is around 300dpi which means that same image will print at about 12 x 8 at that resolution. That's not saying you can't print it larger it's just that the quality will suffer as there will be fewer dots per inch. Glossy magazines will generally print at about 600dpi and some at 1200dpi so the same image would print at 6x4 or 3x2.

There's one more thing that enters into this and that's interpolation. Note that you can print this image at 600dpi and tell it to print at 12x8. The computer will interpolate (compute an average) for the missing pixels which may be fine or may make the print look crappy. It depends on the original quality of the image as Marko was saying.

[Yisehaq]

Thanks Marko & Inguanasan.
Wow, I thought I was missing something but didn't know that I was completely in the dark.

[Yisehaq]

Just curious?!?! Is there anything like boosting pixels so that one can print the picture in a larger format?

[Iguanasan]

You can always print larger but the larger you get the more detail you lose. There becomes a tipping point where the image no longer looks good. This is why it's so important to get the image right in the camera. You can add pixels through interpolation to make larger prints but you can't create more detail in the image. You need a very sharp clear image with lots of pixels to get very large prints.