Image Printing

jgs001

jgs001

Brian Cox
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John
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Not sure where to post this, so this seems to be the best option.

I've just been looking at image printing and sizes, as I was thinking about maybe getting a couple of posters done for my office space. It makes sense to me that a camera of a set resolution will have a maximum print size before the image will start to pixelate or at least appear to. The 450d produces images of 4272x2848 (12Mp) pixels. Now, I found a tool that allows you to enter the image resolution and gives a maximum print size. In this case about 14x9 (inches). To date, I've only printed a couple out at A4 and smaller and they have been fine. How far can an image be enlarged before the resultant print becomes difficult to view ?
 
This will depend on how close you are to the image/poster.
 
I have on my living room wall a 20"x30" print of the Red Arrows, taken on my 6MP D50 a couple of years ago. Fantastic quality, much commented upon...

Photo's from your 450D will make poster-sized prints no problem at all!
 
The answere depends on the image. I've had images from 6-8Mpixel cameras printed up to 20 x 30 ". OK I used a good lens, didn't over process the image and kept sharpening down to a minimum. Also remember you are not going to be looking at these images only a few inches away from your face so what may not look sharp at 6 inches may be OK at 60.

Best suggestion I can make is print a section of the image to A4 that has detail in and would be the same size as the poster you want printed. That way you can judge what's good and what's not.

Personally I wouldn't bother with up sizing to get the required pixels you need for the poster print. You aren't adding any detail,only additional pixels to the data that's there already. Most printer systems will do that for you anyway. However some labs require this so if they do up res, if they don't, don't bother
 
Thanks for the answers all, and Chappers I like the idea of a test print at A4. I'll do that. :thumbs:
 
There is NO maximum size.

As 68lbs noted, the distance from which you're looking at the picture is critical.

With a 450D you can make a 12"x8" print which has 356 ppi (pixels per inch) and, assuming your lens is good and that it's in focus etc, it will look sharp even really close up.

If you go for 24"x16", it's only 178 ppi and it will appear slightly pixellated if you stand right close to it - but you'll typically be looking at it from a few feet away and it will look good.

At 48"x32" you've only got 89 ppi, but you need to stand a fair way back to take it all in and from that distance it will again look good.

If you print out each pixel on a piece of paper a foot square, you can assemble them on a disused airfield and it will look brilliant on Google Earth. Though that would be a bit pricey. (And it would look very pixellated close up.)

There's a general rule of thumb which says that the optimal viewing distance for an image is the same as the diagonal measurement of the image. It can be shown mathematically that a 6 MP image will look sharp at any size if viewed from the optimal distance. Yes, that wasn't a typo. 6 MP.
 
Thanks very much for the info Stewart, that's definitely helped :thumbs:
 
I've had a quick test this morning, based on Chappers suggestion, and it looks like even enlarged to the size I want there isn't going to be a problem. Thanks for the help everyone.
 
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