Maximum *clear* print sizes/ mp?

[commongrackle]

I am wondering how large of a print...a sharp, clear print...I can get from say, a 12.3MP camera? Would the quality of a print be better coming from a DSLR or just a regular digital camera of the same MP?

[teaking]

You will easily get over A3 print sizes with 12MP camera's and thats with the print glued to your forehead so you can see the tiny detail

So in real terms you can go way over that size as the bigger the print the further away you would usualy view it so I would say with 12MP you could possibly go up movie poster sizes and beyond when you take into account viewing distance.

On the camera front Its really down to sensor size On a DX or a cropped sensor pixels are squeezed in and that sometimes equates to more noise than actual more pixels its usualy worse on compact cameras compared to DSLRs. And FX or full frame cameras with there larger sensors usualy give the better resolutions and clearer pixels so if you can afford it a full frame DSLR would give you the better images technically speaking... but you also get more of a viewing angle so lenses work a bit differently.

[commongrackle]

Thanks, teaking. Very helpful.

[BCampbell]

The general standard is 300ppi (pixels per inch) when printing. This is usually what's called for when submitting almost anywhere and resolutions beyond this generally give diminishing returns.

So this means that for, say, a 5"x7" print, you'd want 1500x2100 pixels -- about 2.5MP. 11"x14" is 3300x4200 ; just shy of 14MP.

You can also reverse the math to find out the largest acceptable size a file of certain dimensions will give you, too.

[drr0b]

Originally Posted by BCampbell

The general standard is 300ppi (pixels per inch) when printing. This is usually what's called for when submitting almost anywhere and resolutions beyond this generally give diminishing returns.

So this means that for, say, a 5"x7" print, you'd want 1500x2100 pixels -- about 2.5MP. 11"x14" is 3300x4200 ; just shy of 14MP.

You can also reverse the math to find out the largest acceptable size a file of certain dimensions will give you, too.

Having said that, you can get away with a lot less DPI if the colour gradation is smooth.

This is a 100% crop of a photo that I took this morning with my 500D and 50mm/1.8 prime


This has a resolution of 72 dpi,meaning that the whole photo is 66"x44"! It's not perfectly sharp, but that's because I'm a newbie, and only had the camera for a week

Here is the whole scene

[BCampbell]

Originally Posted by drr0b

Having said that, you can get away with a lot less DPI if the colour gradation is smooth.

This has a resolution of 72 dpi,meaning that the whole photo is 66"x44"! It's not perfectly sharp, but that's because I'm a newbie, and only had the camera for a week

Sorry, I should have been clearer, dpi and ppi are two different things. When you resize an image in Photoshop and it says "72 dpi" that doesn't tell you much about what your safe printing dimensions are.

Basically, as you can guess, the more data you have in an image at a specific size, the better it will look at that size. Let's take this backward; say we have an image that's 3000x3000 pixels. If we print this at 5x5", we have 600ppi -- pixels per inch. If we increase it to 10x10", we have 300ppi, effectively less data in any individual square inch. Keep increasing print size without increasing resolution -- at 30x30" we have 100ppi -- and you start being able to resolve the boundaries between individual pixels with your eyes, giving you some ugly results.

The footnote here is that at extreme sizes, a viewer will be standing far away, and you can thus get away with slightly lower resolutions.

To put it another way, think of Legos. If you have a blank 10x10 tile, you can place 100 1x1 bricks on it to form a pattern, giving you "100bpt", bricks per tile. If you switch to 2x2 bricks, which take up four times as much space, you can only fit 25bpt in the same space, and can't make as detailed a pattern.

300ppi is a pretty good standard to follow, though 150ppi returns perfectly acceptable results, especially on some more modern printing devices (like what you'd find at printing labs). Again, the larger the print size, the more forgiving a lower resolution will be.

Searching for "dpi vs ppi" (or vice versa) will probably explain it way better than I can. But, put simply, divide each dimension of your file (in pixels) by 300 to find your maximum print size at high quality, and by 150 to find your maximum print size at acceptable quality.

[teaking]

There is another option for semi professional results which is to interpolate your image photoshop has a Bi-Cubic enlargement feature which gives pretty good results from 6MP files and while it may not be considered the best method to create extra pixels they do a pretty good job. So if PPI is a major concern for example sending files to publications you could use this method to meet those guidelines and maintain the quality of the image if done Correctly.

[drr0b]

Originally Posted by BCampbell

Sorry, I should have been clearer, dpi and ppi are two different things. When you resize an image in Photoshop and it says "72 dpi" that doesn't tell you much about what your safe printing dimensions are.

Actually, I think I may have been the one who was unclear. I set the resolution of the image to 72 ppi and set the zoom to print size. I assume that this is an accurate representation of what the quality would be like at 72 ppi (but I could be wrong). Is it so unreasonable that a resolution of 5184 dots per square inch gives a nice result ?

[Gonzo13]

It depends on a few things, I have had my 10 mp images printed as 11 x 14 which was about 230 or so dpi. It is hanging on a wall and it looks great. I have also printed a section of a picture from the same camera at 108 dpi which made it a 24 x 36 inches or 2 x 3 feet. If it was placed on a wall about 6 or 7 feet away it looked fine. If I held it at arms length though I could see the blockiness of the pixels. It is like the Pointillism paintings that Georges Seurat created.

[drr0b]

Could it be noise dependent? I've added 8% Gaussian noise to the duck in the image below and it's clearly pixellated


This supports my suggestion that smooth colour variation may result in "clearer" pictures at lower ppi