What Determines Maximum Final Print Size

[rfdesigner]

I think we've all more or less covered most aspects.

My personal take on 300ppi is that at that resolution you can't see print artifacts. HOWEVER you are starting to lose detail in the print as well!

so if you upsample from say 200ppi to 300ppi then you are closer to being able to see all the information in the data, while also not seeing print artifacts. Yes Print at 300ppi, but you can create those from a coarser image... 200ppi original seems fine.. even for a wall print that people will look closely at... which means a 100ppi original scale would be fine viewed from a couple of feet away.

This all seems to tally with other sources where I've seen 8Mpix quoted as good enough for A3 printing.. it's even in the 6D manual that 5MP is good for A4 and ~9MP is fine for A3 (I was flicking through it yesterday, and noticed this)

As to Epson printers.. yes they're weird, I've tried all sorts and got best results on mine at 288ppi... 360ppi was also good, as was 240ppi.

 

[privatebydesign]

Consider that when you create images for the screen the typical PPI for the image is 72.

The 72ppi 'standard' for screen images died a long time ago, now screen resolutions are all over 100ppi, retina screens well over 200ppi.

Sigh

And many mobile devices are over 300ppi now too

 

[ray5]

Consider that when you create images for the screen the typical PPI for the image is 72.

The 72ppi 'standard' for screen images died a long time ago, now screen resolutions are all over 100ppi, retina screens well over 200ppi.

Sigh

And many mobile devices are over 300ppi now too

Though I understand that my file is good enough for a good sized print to be mounted at home I am still unclear about the ppi/dpi issue. How is it that reducing the ppi one can get a larger print but at a lower resolution and vice versa? Thx
Ray

 

[rfdesigner]

Consider that when you create images for the screen the typical PPI for the image is 72.

The 72ppi 'standard' for screen images died a long time ago, now screen resolutions are all over 100ppi, retina screens well over 200ppi.

Sigh

And many mobile devices are over 300ppi now too

Though I understand that my file is good enough for a good sized print to be mounted at home I am still unclear about the ppi/dpi issue. How is it that reducing the ppi one can get a larger print but at a lower resolution and vice versa? Thx
Ray

ppi= pixels per inch

if you have 1000 pixels wide and print at 100 ppi you get 1000/100 = 10 inches, if you print at 200 ppi you get 1000/200 = 5 inches.. you it's 10 inches wide with "low" 100ppi res or 5 inches wide with "higher" 200ppi.

upscaling the image is generally desirable if you'd otherwise be printing at less that 300ppi.

 

[risc32]

i just hit print, or send it out. It always looks good, so either this doesn't matter, I'm blind(and everyone else who looks at the prints), I'm just lucky, or the software just does what needs to be done. I vote for the last option. I have never fooled with any of this. I've printed 15x10's from a 6mp cam a decade ago that look great.

 

[Famateur]

To answer your question, as written in the thread title, you are only limited by the size of paper a printer can accommodate (hence Dilbert's answer). Having been in your shoes before, I'm pretty sure that's not what you're really asking.

There are really two aspects to your question about resolution and print size:

1) Determining Physical Dimensions

This is the easy part because it's just simple math: Take the pixel dimensions for height and width of the image and divide each by a chosen PPI (Pixels Per Inch).

Example: Image with pixel dimensions of 5760x3840

• At 300 PPI: 19.2" x 12.8" Print Size
• At 240 PPI: 24" x 16" Print Size
• At 100 PPI: 57.6" x 38.4" Print Size

* Note that changing PPI does NOT alter the image file or its pixel resolution. It simply tells the printer the physical dimensions to produce (i.e. How big should it print each pixel?).

If you want to print at a finished physical size and don't have enough pixels for the chosen PPI, you'll need to first scale (resize) the image. See below for deciding whether to scale the image and print at higher PPI or simply reduce the PPI.


2) Print Quality

At a high level, and excluding the quality/resolution of the original image, print quality is driven by the relationship between pixel density of the printed image and distance from the viewer to the print. This is where it becomes more art than science because everyone will have a different opinion of what quality is acceptable (or even what detail is visible to their eyes).

Recommendations of printing at 240 or 300 PPI are helpful because they're a generally good place to start for typical print sizes and viewing distances. That said, you'll need to choose what works best for you for a given print job.

I second mb66energy's suggestion to print a cropped section (like the point of focus in the image) as a small print at various PPI choices to get a feel for quality at full print size and expected viewing distance without wasting the ink and paper of a full print for each.


Extra Info...

Part of the confusion is that people mistakenly say DPI when they should be saying PPI. They are not interchangeable.

PPI = Pixels Per Inch.

DPI = Dots Per Inch.

PPI is for display, like pixels in an image or pixels on a monitor. DPI is strictly a hardware specification of how many drops of ink a printer can/will cram into one linear inch when printing those pixels. When you print a 300 PPI image, the physical dimensions of the printed image will be exactly the same, regardless of whether the printer printed at 300, 600 or 1200 DPI.

In other words, when considering final print dimensions, you generally only need to concern yourself with PPI.

What I do...

My printer's max capacity is 13"x26", though 13"x19" is more typical for my largest in-house prints. Uncropped resolution of my images is usually 3648x5472. The best quality I can achieve for my 13"x19" prints is about 280 PPI. With a sharply focused image, and to my eye, I find that 280 PPI holds up beautifully to nose-on-glass viewing distance. Okay, more like six inches because I can't get any closer than that and still focus my eyes...

 

[jrista]

I wrote this article years ago, but it should be helpful in determining the maximum print size you can go with for a given PPI and VIEWING DISTANCE (which is really key here):

http://jonrista.com/2013/12/16/generating-high-quality-inkjet-prints/

Viewing distance is determined by visual acuity, and for most people, you can get away with fairly significant enlargements at low PPI so long as a proper viewing distance is maintained.

 

[rfdesigner]

I wrote this article years ago, but it should be helpful in determining the maximum print size you can go with for a given PPI and VIEWING DISTANCE (which is really key here):

http://jonrista.com/2013/12/16/generating-high-quality-inkjet-prints/

Viewing distance is determined by visual acuity, and for most people, you can get away with fairly significant enlargements at low PPI so long as a proper viewing distance is maintained.

cracking write up there jrista, thanks for sharing

 

[LDS]

Part of the confusion is that people mistakenly say DPI when they should be saying PPI. They are not interchangeable.

Also, the relationship between DPI and PPI depends on the printer (or any other output device) technology. Inkjet printers (and other half-tone technologies) need several dots in appropriate patterns to represent a single pixel color. Other technologies, for example dye-sublimation, and other continuos-tone technologies, may have a 1:1 relationship.

Thereby, while DPI for an inkjet printer *might* tell how sophisticated the pattern and its quality could be (number, quality of inks and the algorithm calculating the pattern are important also), when it comes to the actual output resolution what matter is the PPI.

 

[ray5]

To answer your question, as written in the thread title, you are only limited by the size of paper a printer can accommodate (hence Dilbert's answer). Having been in your shoes before, I'm pretty sure that's not what you're really asking.

There are really two aspects to your question about resolution and print size:

1) Determining Physical Dimensions

This is the easy part because it's just simple math: Take the pixel dimensions for height and width of the image and divide each by a chosen PPI (Pixels Per Inch).

Example: Image with pixel dimensions of 5760x3840

• At 300 PPI: 19.2" x 12.8" Print Size
• At 240 PPI: 24" x 16" Print Size
• At 100 PPI: 57.6" x 38.4" Print Size

* Note that changing PPI does NOT alter the image file or its pixel resolution. It simply tells the printer the physical dimensions to produce (i.e. How big should it print each pixel?).

If you want to print at a finished physical size and don't have enough pixels for the chosen PPI, you'll need to first scale (resize) the image. See below for deciding whether to scale the image and print at higher PPI or simply reduce the PPI.


2) Print Quality

At a high level, and excluding the quality/resolution of the original image, print quality is driven by the relationship between pixel density of the printed image and distance from the viewer to the print. This is where it becomes more art than science because everyone will have a different opinion of what quality is acceptable (or even what detail is visible to their eyes).

Recommendations of printing at 240 or 300 PPI are helpful because they're a generally good place to start for typical print sizes and viewing distances. That said, you'll need to choose what works best for you for a given print job.

I second mb66energy's suggestion to print a cropped section (like the point of focus in the image) as a small print at various PPI choices to get a feel for quality at full print size and expected viewing distance without wasting the ink and paper of a full print for each.


Extra Info...

Part of the confusion is that people mistakenly say DPI when they should be saying PPI. They are not interchangeable.

PPI = Pixels Per Inch.

DPI = Dots Per Inch.

PPI is for display, like pixels in an image or pixels on a monitor. DPI is strictly a hardware specification of how many drops of ink a printer can/will cram into one linear inch when printing those pixels. When you print a 300 PPI image, the physical dimensions of the printed image will be exactly the same, regardless of whether the printer printed at 300, 600 or 1200 DPI.

In other words, when considering final print dimensions, you generally only need to concern yourself with PPI.

What I do...

My printer's max capacity is 13"x26", though 13"x19" is more typical for my largest in-house prints. Uncropped resolution of my images is usually 3648x5472. The best quality I can achieve for my 13"x19" prints is about 280 PPI. With a sharply focused image, and to my eye, I find that 280 PPI holds up beautifully to nose-on-glass viewing distance. Okay, more like six inches because I can't get any closer than that and still focus my eyes...

Excellent explanation. I am going to save this for my files. Thank you!

 

[ray5]

I wrote this article years ago, but it should be helpful in determining the maximum print size you can go with for a given PPI and VIEWING DISTANCE (which is really key here):

http://jonrista.com/2013/12/16/generating-high-quality-inkjet-prints/

Viewing distance is determined by visual acuity, and for most people, you can get away with fairly significant enlargements at low PPI so long as a proper viewing distance is maintained.

Very simple to understand. Thanks.

 

[Famateur]

Excellent explanation. I am going to save this for my files. Thank you!

You're most welcome, Ray5! Glad I could help.

 

[RGF]

Just an FYI -- I had a 1D M2 (?) which was 11 MP. I shot a bull moose shredding its velvet.

I cropped the image by ~50% and printed an 12x18 which really good. So out of an essentially 6 to 7 MP image I got an 12x18 print.

 

[TexPhoto]

Maximum final print size? A good rule of thumb is smallest side of the print no wider than the width of the printer.

Higher DPI is great, but there is no hard and fast rule. 300DPI images look great, 299DPI images? Great.

One of my images is displayed in an advertisement at my local airport. I's a 6MP image from my Nikon D70. (Back in the day) It's about 30 feet wide on the wall and starts about 10 feet up. Cropped to a Panorama. Looks great. Would a 50MP camera have produced a sharper image on that wall? Probably.