Increasing image size. How far?

Richmate

Richmate

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442
Name
Richard
Edit My Images
Yes
Hi

I know the basics of how to increase image size in LR and PS but im always wondering as to how far I can push it. I mean if I took my raw file from my 5dmkii which is approx 20" x 13" how far could I increase the size before I would start to notice some quality issues when printed. I know several factors come in to play especially the resolutions and quality of the image in the first place, but Im intrigued to find out how others approach and assess this when printing their photos.

Thanks in advance

Rich:)
 
I've printed 48inch x 36 inch with that camera no problem . I also had a client use one of my images for a trade show they were doing and it must have been 30 foot x 20 foot easily , I was shocked just how well it looked !
 
Richmate said:
I mean if I took my raw file from my 5dmkii which is approx 20" x 13" how far could I increase the size before I would start to notice some quality issues when printed.
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It depends *totally* on how closely you're looking at your printed image.

The sensor of the 5D Mk II delivers images which measure 5616 x 3744 pixels. The usual rule of thumb is that with 20/20 vision you can resolve about 300 pixels per inch (ppi) when viewed from a distance of 12". So that means your print could be about 19" x 12.5". I think this is basically the same calculation that was used to come up with your size of 20" x 13"; your calculation was based on about 280 ppi instead of 300 ppi but the difference is negligible.

So in one sense you already have your answer. If you view your print from a distance of 12", which for many people is about as close as they feel comfortable with, then you might start to see pixellation when you go bigger than 20" x 13". And it all scales linearly with distance. If you can focus clearly from a range of 6" (I can't) then you would have to limit your print to about 10" x 6.5". If you look at it from a range of 24" then you should be OK with print sizes up to about 40" x 26". And so on. If you wanted to print it very very very large and look at it from the International Space Station, about 240 miles up, the maximum image size would theoretically be 400 x 260 miles which is comparable to the size of England. (Though I think atmospheric effects might be significant there, so the theory probably breaks down.) (And the ink would be a bit expensive.)

Does that help?

One additional concept which may be important is the "natural" viewing distances for images of different sizes. Scientists have watched people in art galleries to see how closely they tend to look at pictures of different sizes. Look more closely and you can see more detail; stand back a bit and you can appreciate the whole image more. It turns out that the "natural" viewing distance is about the same as the diagonal measurement of the image, and if you plug that into the resolution and ppi equations it shows that you can make prints *as large as you like* and they will never appear to be pixellated when viewed from the "natural" distance. (In fact you only need 6 megapixels to achieve this, so your 21 megapixels is more than enough.)
 
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stumac said:
I've printed 48inch x 36 inch with that camera no problem . I also had a client use one of my images for a trade show they were doing and it must have been 30 foot x 20 foot easily , I was shocked just how well it looked !
Click to expand...
Thanks Stuart. Wow, you must have been chuffed to bits (y)



StewartR said:
It depends *totally* on how closely you're looking at your printed image.

The sensor of the 5D Mk II delivers images which measure 5616 x 3744 pixels. The usual rule of thumb is that with 20/20 vision you can resolve about 300 pixels per inch (ppi) when viewed from a distance of 12". So that means your print could be about 19" x 12.5". I think this is basically the same calculation that was used to come up with your size of 20" x 13"; your calculation was based on about 280 ppi instead of 300 ppi but the difference is negligible.

So in one sense you already have your answer. If you view your print from a distance of 12", which for many people is about as close as they feel comfortable with, then you might start to see pixellation when you go bigger than 20" x 13". And it all scales linearly with distance. If you can focus clearly from a range of 6" (I can't) then you would have to limit your print to about 10" x 6.5". If you look at it from a range of 24" then you should be OK with print sizes up to about 40" x 26". And so on. If you wanted to print it very very very large and look at it from the International Space Station, about 240 miles up, the maximum image size would theoretically be 400 x 260 miles which is comparable to the size of England. (Though I think atmospheric effects might be significant there, so the theory probably breaks down.) (And the ink would be a bit expensive.)

Does that help?

One additional concept which may be important is the "natural" viewing distances for images of different sizes. Scientists have watched people in art galleries to see how closely they tend to look at pictures of different sizes. Look more closely and you can see more detail; stand back a bit and you can appreciate the whole image more. It turns out that the "natural" viewing distance is about the same as the diagonal measurement of the image, and if you plug that into the resolution and ppi equations it shows that you can make prints *as large as you like* and they will never appear to be pixellated when viewed from the "natural" distance. (In fact you only need 6 megapixels to achieve this, so your 21 megapixels is more than enough.)
Click to expand...

Thanks for the detailed and interesting explanation Stewart. That all makes perfect sense and helps massively (y).

StewartR said:
If you wanted to print it very very very large and look at it from the International Space Station, about 240 miles up, the maximum image size would theoretically be 400 x 260 miles which is comparable to the size of England. (Though I think atmospheric effects might be significant there, so the theory probably breaks down.) (And the ink would be a bit expensive.)
Click to expand...
Ha, I love this bit :)
 
The ink would be expensive but for a project like that you could probably get some sort of grant from the Arts Council.
 
StewartR said:
It depends *totally* on how closely you're looking at your printed image.

The sensor of the 5D Mk II delivers images which measure 5616 x 3744 pixels. The usual rule of thumb is that with 20/20 vision you can resolve about 300 pixels per inch (ppi) when viewed from a distance of 12". So that means your print could be about 19" x 12.5". I think this is basically the same calculation that was used to come up with your size of 20" x 13"; your calculation was based on about 280 ppi instead of 300 ppi but the difference is negligible.

So in one sense you already have your answer. If you view your print from a distance of 12", which for many people is about as close as they feel comfortable with, then you might start to see pixellation when you go bigger than 20" x 13". And it all scales linearly with distance. If you can focus clearly from a range of 6" (I can't) then you would have to limit your print to about 10" x 6.5". If you look at it from a range of 24" then you should be OK with print sizes up to about 40" x 26". And so on. If you wanted to print it very very very large and look at it from the International Space Station, about 240 miles up, the maximum image size would theoretically be 400 x 260 miles which is comparable to the size of England. (Though I think atmospheric effects might be significant there, so the theory probably breaks down.) (And the ink would be a bit expensive.)

Does that help?

One additional concept which may be important is the "natural" viewing distances for images of different sizes. Scientists have watched people in art galleries to see how closely they tend to look at pictures of different sizes. Look more closely and you can see more detail; stand back a bit and you can appreciate the whole image more. It turns out that the "natural" viewing distance is about the same as the diagonal measurement of the image, and if you plug that into the resolution and ppi equations it shows that you can make prints *as large as you like* and they will never appear to be pixellated when viewed from the "natural" distance. (In fact you only need 6 megapixels to achieve this, so your 21 megapixels is more than enough.)
Click to expand...
Thanks for all this information. Super helpful!
 
I recall seeing a BBC programme where they hung an image of Suzie Perry down the side of a tower block. The 'pixels' were the size of tennis balls but it looked great from 1/2 mile distant :)

Mind you, Suzie Perry looks good anywhere;)
 
Norkie said:
I recall seeing a BBC programme where they hung an image of Suzie Perry down the side of a tower block. The 'pixels' were the size of tennis balls but it looked great from 1/2 mile distant :)

Mind you, Suzie Perry looks good anywhere;)
Click to expand...


I've used The Rasterbator http://rasterbator.net a few times, you'd be surprised how big the pixels can be and how close you can be standing for the image to still make sense. Printing out it look s like all you'd see is big dots, but it doesn't work like that. I had a venue in t past and we had image s of a drum kit and a mic up on one wall, cost next to nothing to print on a laser printer, took a bit of time for someone to stick together but they must have been 12' wide images and once up looked good. Obviously they were far from clear, but you could read the brand names on the equipment, and they made the wall look good. You also don't need to be accurate sticking the sheets together. I've let a kids club print and make large images before, they have hours of fun and make posters the size of a house.
 
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