How big can you go with your photos?
Revamping your office in the New Year?
How big can you go with your photos?
Somehow that guy, Pythagoras of Samos, always seems to crop up in your life. I thought he'd left mine on the final day I walked out of high school a looooong time back, but - no - he's still around. And even interfering in my photography! Before I go any further, in case any of you suffer from high-school amnesia, let me remind you - Pythagoras' theorem is a² + b² = c²
OK - and?
Well, ever look at an advertising billboard or display photograph from a long way off and say something on the lines of "they must have a great camera / lens / they're a professional photographer" etc etc...." Well, believe it or not, next time you look through your photo library, you may be looking at a 20 metre wide image ready to be hung up on your office wall.
Now just before you all go off rushing to the nearest print shop, let's drag our friend Pythagoras back into the room. As a general rule of thumb, the distance you will view your display photo is approximately twice the diagonal measurement of the image in question. Let's say for the sake of argument, you have a 30 x 20cm square photo you want to hang up. So the diagonal, as per Pythagoras, is 30² + 20² which is 900 + 400 = 1300 but as 1300 is the squared amount, the square root of 1300 is 36cm approx. And as we've already said the viewing distance is approx twice this amount, then we're talking around 75cm from which you should view your photo.
So that's the easy bit!
But unfortunately - or maybe fortunately as goodness knows what theories he'd have come up with - Pythagoras lived before the digital era. So he wasn't thinking of printing digital photos when he was sunbathing on Samos.
The next factor to consider doesn't have an easy mathematical formula - that is, what resolution your image has to be when viewed from a specific distance. The photography industry has us all bombarded with the MP (megapixel) capacity of your phone. Mobile or otherwise. Not wanting to go down this particular rabbit hole, let's confirm that my current iPhone 13 is boasting a 12MP camera. And that my trusted, and ageing, Fujifilm X-T2 has double this, 24MP
Even a 12MP camera will give you an image of 4000 x 3000 pixels which believe it or not, is good for a 6.75 metre print! But not at full resolution which is usually quoted at 300dpi (dots per inch). Again there are many rabbit holes here but, successfully avoiding them again, take the fact that most billboards are printed at 15dpi, which - again trust me(!) - is the equivalent of just over a 2MP camera! In other words, far and below what your mobile phone camera is giving you.
The secret here is that as your print size increases, so does the viewing distance. Walk - or climb(!) - up to a billboard and you'd see that the print resolution is terrible. But nobody ever stands this close to a billboard - no matter what they're advertising.
In summary
If you want your photo to be printed at full 300dpi resolution, then your friend Pythagoras will come knocking with his calculations above. But if you're prepared to print larger sizes at a lower resolution, then really, the skies your limit. Provided you don't want to come up close and personal to your photo.
We've avoided many rabbit holes in this short read, but this really all relates to not necessarily being restricted by thinking you need a professional print.
Think more about how far away you will look at your image from before you press Cmd + P.
If you're talking just a a couple of metres or less, then engage Pythagoras. Print at full resolution (300dpi) and restrict yourself to a print size calculating that the distance you will view your display photo is approximately twice the diagonal measurement of the image in question.
But if you're looking to mount an image in your conference room, then think outside the 300dpi box and realise you can print at 15dpi and view from 15 metres easily.
Hope this helps your next decorating phase!
