Print resolutions

[ThePhotoDude]

I'm setting up a little tool to help my customers see what resolution their file will print at given the amount of pixels.
To often I end up having to contact people that send me their files to print, only to explain that the photo that they've lifted from the internet really IS too small for me to print at 100cm x 70cm!

So, I have a tool which you browse to the photo, enter in your desired print width and height.
From there the tool works out the print resolution and displays to the customer of a scale of 1-5 the expected quality of the output.
I know there are obviously many factors that will determine what the print will look like, focus, media, subject etc etc.

But for the purposes of this tool and this thread I'm really interested in the levels of scale for output resolution.

So, a survey, because I'm sure everybody will have a different idea.
On a scale of 1 -5 (where 5 is the best quality and 1 is the worst) - I only want 5 levels or it gets to complicated - what are the ranges of DPI, (PPI?) that I should use.
Bear in mind that the bigger a print is, the further away one views it from, so a lower resolution can be used in some cases.

So far this is what I have:

1-- - 0-50 ppi or dpi
2-- - 51-80
3-- - 81-120
4-- - 121-219
5-- - 220+

I would welcome any comments and suggestions,

Thanks, John

[Dick Roadnight]

I'm setting up a little tool to help my customers see what resolution their file will print at given the amount of pixels.

On a scale of 1 -5 (where 5 is the best quality and 1 is the worst) - I only want 5 levels or it gets to complicated - what are the ranges of DPI, (PPI?) that I should use.
Bear in mind that the bigger a print is, the further away one views it from, so a lower resolution can be used in some cases.

So far this is what I have:

1-- - 0-50 ppi or dpi
2-- - 51-80
3-- - 81-120
4-- - 121-219
5-- - 220+

I would welcome any comments and suggestions,

Thanks, John

I would suggest that the two top levels should be 240 and 360 (or 300 depending on the default/optimum res of you printer).

I think that a print that contains fine detail, or subjects within the picture, should ideally look good close up with reading glasses on, even if they are printed 5*20 feet.

In shots like misty sunrises you can get away with low res (and this is the chosen "style" of many photographers who have not got the kit or (stitching) capability to do any better, and some low-res pictures can be improved by blurring out the pixelation/grain/noise.

[alain]

I'm setting up a little tool to help my customers see what resolution their file will print at given the amount of pixels.
To often I end up having to contact people that send me their files to print, only to explain that the photo that they've lifted from the internet really IS too small for me to print at 100cm x 70cm!

So, I have a tool which you browse to the photo, enter in your desired print width and height.
From there the tool works out the print resolution and displays to the customer of a scale of 1-5 the expected quality of the output.
I know there are obviously many factors that will determine what the print will look like, focus, media, subject etc etc.

But for the purposes of this tool and this thread I'm really interested in the levels of scale for output resolution.

So, a survey, because I'm sure everybody will have a different idea.
On a scale of 1 -5 (where 5 is the best quality and 1 is the worst) - I only want 5 levels or it gets to complicated - what are the ranges of DPI, (PPI?) that I should use.
Bear in mind that the bigger a print is, the further away one views it from, so a lower resolution can be used in some cases.

So far this is what I have:

1-- - 0-50 ppi or dpi
2-- - 51-80
3-- - 81-120
4-- - 121-219
5-- - 220+

I would welcome any comments and suggestions,

Thanks, John

Anything without a minimum viewing distance mentioned is rather pointless.

Some info :

http://www.northlight-images.co.uk/article...g_distance.html

There could also be some info about the "optium" viewing distance versus the size of the print.


 

[Bruce Watson]

Bear in mind that the bigger a print is, the further away one views it from, so a lower resolution can be used in some cases.

I love the concept of "correct viewing distance". I understand it, I've tested it, and I know it works for me. But...

Sadly, most people who view art don't pay a lot of attention to this concept. As part of my "research" I've watched other people at galleries looking at my prints, prints from other photographers, paintings, watercolors, sculptures, all kinds of things, just to see how they approach a piece of art. What I've found is that many people will glance at a work from across the room, register it, and move on -- they aren't interested. Some of these people will register it, then walk toward it, then veer off -- they aren't interested enough to spend any more time on it. Some of these people will walk toward it, move again (nearly always to a point close to the "correct viewing distance") and study it a while before moving off -- these people are actually interested in it. Then there's the last subset of people who, after looking at it from the "correct viewing distance" will move in farther and have a good close look. This last group are the ones who will then turn and seek out the artist or gallery owner. Or give that disappointed look down at their feet, shake their heads, and walk off to some other artists work.

This observed behavior caused me to run some experiments where I've scanned the same film at different resolutions for the same print size, printed sections, put them side-by-side under the same lighting, and looked at them from various distances, and shown them to others. When I show them to others I ask just one question: "which one do you like best?" I don't tell them what the differences are, and I don't ask them to evaluate differences -- just which one do you like best? They never pick the 240ppi print. About 25% pick the 300 ppi print. About 75% pick the 360 ppi print. Interestingly to me anyway is that about half look at the prints from the "correct viewing distance" and the rest from both there, and closer. Maybe 25% get to within about 30 cm (12 in). I don't prompt them or show them were to stand (I stay out in the hallway).

So... I advise anyone interested in this stuff to run their own experiments. I'm sure the results will vary some due to different equipment (scanners, printers, etc.), different settings, different images, different artistic viewpoints, different skill levels, etc. IOW, my tests don't necessarily tell you anything about how it will work out for you. Do the tests -- it's not hard. Why guess when you can know?

[JeffKohn]

One thing I'll put out is that you can't directly relate PPI numbers to print quality without considering the source of the pixels. Scanning film is different than digital capture, and you won't need as high of a PPI with digital capture to reach a certain quality as you would with scanned film.

[Dick Roadnight]

I love the concept of "correct viewing distance". I understand it, I've tested it, and I know it works for me. But...
About 75% pick the 360 ppi print.

I had already concluded that I would print most of my work at 360 ppi... but that would be 360 original (AA-filter free) camera pixels per print inch.

...Both the P65+ and the H4D-60 fill the width (long side) of 24" roll paper, and that is a reason for upgrade, and with shift-and -stitch I should be able to produce some quality work.

[howseth]

On my HP Z3100 I always make my files at the HP recommended optimum - 300ppi - regardless of image size. I then use the highest 'quality' setting on the printer. I do not care how long it takes to print it out. I am not a high volume printer.

Howard

[Colorwave]

Here's another vote for the too many variables to be a meaningful tool feedback.  Unfortunately, I think personal interaction is required to inquire, educate and inform.  Otherwise, it seems you may be scaring some people off and giving others false hope that will lead to disappointment later.

[alain]

I love the concept of "correct viewing distance". I understand it, I've tested it, and I know it works for me. But...

Sadly, most people who view art don't pay a lot of attention to this concept. As part of my "research" I've watched other people at galleries looking at my prints, prints from other photographers, paintings, watercolors, sculptures, all kinds of things, just to see how they approach a piece of art. What I've found is that many people will glance at a work from across the room, register it, and move on -- they aren't interested. Some of these people will register it, then walk toward it, then veer off -- they aren't interested enough to spend any more time on it. Some of these people will walk toward it, move again (nearly always to a point close to the "correct viewing distance") and study it a while before moving off -- these people are actually interested in it. Then there's the last subset of people who, after looking at it from the "correct viewing distance" will move in farther and have a good close look. This last group are the ones who will then turn and seek out the artist or gallery owner. Or give that disappointed look down at their feet, shake their heads, and walk off to some other artists work.

This observed behavior caused me to run some experiments where I've scanned the same film at different resolutions for the same print size, printed sections, put them side-by-side under the same lighting, and looked at them from various distances, and shown them to others. When I show them to others I ask just one question: "which one do you like best?" I don't tell them what the differences are, and I don't ask them to evaluate differences -- just which one do you like best? They never pick the 240ppi print. About 25% pick the 300 ppi print. About 75% pick the 360 ppi print. Interestingly to me anyway is that about half look at the prints from the "correct viewing distance" and the rest from both there, and closer. Maybe 25% get to within about 30 cm (12 in). I don't prompt them or show them were to stand (I stay out in the hallway).

So... I advise anyone interested in this stuff to run their own experiments. I'm sure the results will vary some due to different equipment (scanners, printers, etc.), different settings, different images, different artistic viewpoints, different skill levels, etc. IOW, my tests don't necessarily tell you anything about how it will work out for you. Do the tests -- it's not hard. Why guess when you can know?

You're talking about "art to be sold" , it's my impression the topic starter is about people with there own (I hope) work that they want printed.  I was quite happy with a 51 ppcm (130ppi) 41 by 82 cm landscape print, but I can find some artefacts on closer examination inside a viewing booth.    

[ThePhotoDude]

Thanks for the great replies, I know there is a lot of discussion about print quality relating to a billion things more than just pixels per inch, but for the purposes of this tool it's about letting the 'unlearned' have some sort of idea about how their print may look.
Yes I am a print-for-pay printer, some of my clients are professional photographers who know about the topics discussed here, some are simply not.
The tool is simply to set the expectations of those who just don't understand the rest of the concept. I am a high volume printer and I will provide instruction on what makes a great print, but this tool is something handy.

Dick, thank you for some feedback on the numbers involved. I guess this means that level 3 should have a greater range then I have, this makes sense, it's the 'Average' the 'OK' resolution. My printers natural output is 300, Z3100, so would anything above 300 be considered level 5? and Alain, Excellent article, I will make good use of this, thank you.

Viewing distance is important, a billboard looks great from 300 meters away, at 5ppi.

Personal interaction and education is not always possible in my business, of course I advise clients who want more information, but the tool is handy for somebody who doesn't understand and just wants their photo of Aunt Betty blown up to A0 for her 60th birthday party. They can see that it will be printed at low res, read the description of what to expect with regard to detail and make a decision, to print it anyway perhaps at a smaller size.

99.9% of the photos that I print are my customers own work, occasionally I will receive a print that's clearly been taken from the internet, but not everybody is seeking perfection here. I had one guy who sent me a 26k file to be printed at 100 x 70cm ! It was a graphic, not a photo but it was AWFUL quality as you can imagine at that size. Guess what, he loved it and ordered some more different ones a week later.