[BarryE]

Another factor to add to this is the paper choice. I tried a similar experiment. I didn't come to exactly the same conclusions, but similar. However the results differ a lot between different papers. One extreme, a high gloss high Dmax paper, compared with, say, an fine art paper. Another, factor is the viewing light and angle, as well as distance, as the OP tried.

In essence lower dpi than 300 easily makes perfectly good large prints, as does modern interpolation techniques allowing lower mp cameras to start with.

Personally, using smart sharpening with PAPER TYPE appropriate levels as well as setting the layer's blending mode to Luminosity to avoid color shifts along edges a quality, large print can be made from far fewer pixels than is normally specified.

[interested_observer]

I've printed a full size K5 image at Costco (20" x 30") for $8.99 which works out at 150ppi and it turned out great. The folks at work took their magnifying glasses to it and it passed their inspection (a bunch of engineers). It's still there hanging on the wall. Now, I reprinted it at a custom printer - pearl metallic paper, better inks, etc., and yes it was better, but probably the last 10%. Costco took the initial 90% of image quality and another $100 took the next 10% to top it off.

So, was it a combination of the overall image quality coupled with the printer up-scaling to its native resolution? Probably, but at 150ppi - I'm not going to worry about it, as it still looks great.

I'm kind of sorta of working on a 19,000 by 11,000 stitched panorama shot with the K1 and DFA*15-30, and something like this would be a test. Costco prints a 20" x 60" for $20, which is doable. Printing a full size 300ppi at 20" x 60", and then smaller sized prints at progressively less dense ppi, say 180ppi, 150ppi and 130ppi, of the same cropped area, would help. But in the end, I think you really need to understand what the actual printer is going to do with the image data it receives.

[pid]

... just print as big as you want. No matter what effective resolution. If the motive is good, the resolution plays only a minor role. No photo of Helmut Newton was as sharp as you would take a picture nowadays, but they are outstanding and a pleasure to look at.

[BarryE]

... just print as big as you want. No matter what effective resolution. If the motive is good, the resolution plays only a minor role. No photo of Helmut Newton was as sharp as you would take a picture nowadays, but they are outstanding and a pleasure to look at.

So true. A print should be thought of as a separate output to a screen image - it is different in many ways, and resolution is only a part. Creating a good print is in itself an art form, extra to the capture. Many famous photographers would print from negatives many times over many years as their darkroom skills and aesthetic changed.

[biz-engineer]

TonyW's comments regarding avoidance of giving the printer driver license are pertinent. They gave me a good schooling.

I've done an 8th print, based on a 125dpi crop (1500x1000), up-sampled 3x (4500x3000), sharpened, compared with the same crop not up-sampled. Makes no difference, it's impossible to set the 1500x1000 and 4500x3000 prints apart. If there is any difference between the 1500x1000 print and its 3x up-sampled version it is the sharpening impact on the edges, the 4500x3000 gets less abrupt edge sharpening (already visible on computer display before printing)., and actually the non- up-sampled print shows smoother bokeh. The way I can explain up-sampling makes no difference on the prints is if the printer uses a very good interpolation algorithm.

[biz-engineer]

Sounds like it's not about the sensor resolution, but about how homogeneous are the lenses to cover the sensor area.

You Tube

You Tube

[normhead]

* At 10", one can tell the difference between 150 and 300 easily.

The difference being that, you can't enjoy the composition of a photograph at 10 ", so it comes down to what do you enjoy in a phototogrpah, composition, or technical clarity from 10". Clarity from 10" brings me no joy at all.

Because we printed a lot of 30x20 (inches) on canvas, our best selling print was barely 100 DPI taken with point and shoot. Of course we blew it up to 300 DPI for the printer. But still the true value in terms of resolution was 100 DPI.

My observation over the years is that people who don't actually do prints, grossly underestimate how good a 100 DPI image can be even printed to 30x20.
Not only that, my wife image taken with an Opito 10 12 MP was better than side by side images taken with my K-5.
The end result of all these recommendations for high DPIs in printing is there are a lot of people who have images that would be great prints hanging on their wall, if they could ignore the internet nonsense, get over the preposterous suggested DPI limits and just print.

The printing community is doing itself a great disservice, although I've notice many have lowered their standards based on actual data from what their customers are actually happy with, as opposed to what the camera companies and printer companies would have you believe. The camera companies don't want you selling 12 MP point and shoot images. They want their cut of your photographic income. The printer companies are just shooting themselves in the feet. And people adopting standards like 200-300 DPI for acceptable printing are simply propagandists.

My advice would be as long as you have a real 100 DPI or over, upscale for the printer used (360 DPI or 300 DPI) print away. If the composition is good, you'll enjoy the print.
I don't care personally if I can see difference. No one ever compares two of the same images at different DPIs in the real world. Unless the difference diminishes my enjoyment of the composition it's moot.

I know the printers want it to be all about the technical ins and outs of the printing, but it's not. It's about composition. The printing just has to be good enough to view from your lap, for a book, maybe 20" or 3 feet if it's hanging on a wall.
I have prints done at 72 DPI that I thoroughly enjoy.

I have never once heard a person say, "That's a great composition but I couldn't enjoy it because the native DPI wasn't high enough."

But I know of many images taken by friends who didn't print their favourite images because a computer analysis on some printing site told them there print was only going to be "good" not "excellent" and then assumed that they could only possibly happy with "excellent." The attitudes of the print community is costing them money.

You can listen to the printers if you want, but they'll just poop on your parade for no good reason. They are way too critical, because in their minds, the technical aspects of printing are important as they should be. But they give really bad advice when it comes to what people will like hanging on their wall, people not including people who want their prints to look as sharp as possible from 10 inches away, which as far as I can tell is hardly anyone.

There's a difference between, "it looks sharper", and "it's more pleasing to look at." And too much detail can actually ruin an image as much as not enough detail can. Resolution must be appropriate to the subject.

This is the opinion of a guy who made money not listening to what printers told him he should be printing. In fact when I found out what printers were recommending, I was completely shocked. By the time I found out what was recommended, I'd already sold over 20 "low res" images.

Needless to say, these days I just print good compositions, you'll never convince me I need more MP for certain size for any image. I'll print whatever image I have to the size the customer wants. I have k-3 file slightly cropped printed on posterboard at 48'x 30 inches. That's 125 DPI. I've already had some interest shown in the print (just from friends who visit me at home) but so far no one likes the price.

So my question would be who are these people who recommend 200-300 Dpi talking to, what's the target market?

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Last edited by normhead; 04-01-2019 at 06:53 AM.

[biz-engineer]

. The printing just has to be good enough to view from your lap, for a book, maybe 20" or 3 feet if it's hanging on a wall.I have prints done at 72 DPI that I thoroughly enjoy.

My print experiment led me to believe that what I see on the print is what I also on my notebook HD IPS display, with my best effort of close vision, I start to see HD pixels but it's an effort that I wouldn't to look at an image.
So, for me now, the calculation is very simple: HD (1920x1280) for 1 A4 tile is already good (not the very best , but good), that means, if I have 6000 x 4000 pixel (K3) I can print 9 x A4 tiles, that's 90 x 60 cm with indistinguishable pixels. If I use a K1 file, I can print 16 x A4 tiles , that 120 x 80 cm with indistinguishable pixels looking close, but if I look at 25 cm from the 120 x 80 cm print there is no way I can see the whole picture, so I have to stand back , and if I stand back the quality is already fantastic. So in fact, if I blew it up to 150 x 100 cm, and stand back to look and the while picture, it's very good. That means, if the image capture was done well, lens is good, fringing corrected by software and the right amount of sharpening, large prints can be make out of K3 files. In fact, the subject matter, quality of exposure and post processing mater more than sensor resolution alone. You can have a more expensive camera and not use it well, and will not get better than a cheaper camera with good technique.

[normhead]

My print experiment led me to believe that what I see on the print is what I also on my notebook HD IPS display, with my best effort of close vision, I start to see HD pixels but it's an effort that I wouldn't to look at an image.
So, for me now, the calculation is very simple: HD (1920x1280) for 1 A4 tile is already good (not the very best , but good), that means, if I have 6000 x 4000 pixel (K3) I can print 9 x A4 tiles, that's 90 x 60 cm with indistinguishable pixels. If I use a K1 file, I can print 16 x A4 tiles , that 120 x 80 cm with indistinguishable pixels looking close, but if I look at 25 cm from the 120 x 80 cm print there is no way I can see the whole picture, so I have to stand back , and if I stand back the quality is already fantastic. So in fact, if I blew it up to 150 x 100 cm, and stand back to look and the while picture, it's very good. That means, if the image capture was done well, lens is good, fringing corrected by software and the right amount of sharpening, large prints can be make out of K3 files. In fact, the subject matter, quality of exposure and post processing mater more than sensor resolution alone. You can have a more expensive camera and not use it well, and will not get better than a cheaper camera with good technique.

And there are times when the more expensive camera is a detriment to actually taking the picture. You can't match the point and shoot, because you'd have to set up tripod, and sometimes there isn't even place to set up tripod, and shoot a long exposure, impossible when there is motion in the scene, to get the same result. Cheap cameras can do amazing things these days.

[biz-engineer]

And there are times when the more expensive camera is a detriment to actually taking the picture. You can't match the point and shoot, because you'd have to set up tripod, and sometimes there isn't even place to set up tripod, and shoot a long exposure, impossible when there is motion in the scene, to get the same result. Cheap cameras can do amazing things these days.

Yes, understood. Also... I'm realize something of the 3:2 format, it doesn't fit as well as 4:3 into a circular image projected by the lens, IQ isn't as good on the left and right edges of the 3:2 frame, than top and bottom of the frame. It is likely better to crop the 3:2 rectangle to 4:3 (cut the left and right edges) prior printing!

[acoufap]

Yes, understood. Also... I'm realize something of the 3:2 format, it doesn't fit as well as 4:3 into a circular image projected by the lens, IQ isn't as good on the left and right edges of the 3:2 frame, than top and bottom of the frame. It is likely better to crop the 3:2 rectangle to 4:3 (cut the left and right edges) prior printing!

I‘d say, crop to support your image’s composition and thus strongness of your message. If anything else shall lead the overall image ratio, it may be your general target format for your presentation(s) - not the sensor’s technically given image ratio ... IMO. - of course that‘s the easiest way ... but always the best?! I doubt it.

[biz-engineer]

I‘d say, crop to support your image’s composition and thus strongness of your message. If anything else shall lead the overall image ratio, it may be your general target format for your presentation(s) - not the sensor’s technically given image ratio ... IMO. - of course that‘s the easiest way ... but always the best?! I doubt it.

Yes, I agree. Simply 4:3 gets rid of the edges, so in case I wanted to print, it's good to have it in mind (I didn't think about it before).

[Fenwoodian]

I have read different studies that conclude the human eye/brain combination can only resolve to about 180dpi. The 300dpi standard comes from the print industry before digital. That's the resolution printers wanted from photographers so they had plenty of room to optimize the photos for magazine publication. It would be interesting to know what the actual final resolution is of the photos on the printed magazine pages.

I print large with my Epson 7600 printer. 180 is about the minimum I'll use for a very large print (e.g. 24x36). For my 24x30 prints I'll use 240, for my 20x24 prints I'll use 288, and for my 16x20 prints I'll use 360..

[Fenwoodian]

Printing a full size 300ppi at 20" x 60", and then smaller sized prints at progressively less dense ppi, say 180ppi, 150ppi and 130ppi, of the same cropped area, would help. But in the end, I think you really need to understand what the actual printer is going to do with the image data it receives.

Each printer manufacturer has their optimum dpi for their machines. For Epson printers it's 180, 240, 288, and 360. Feed an Epson printer these files and it will not need to interpolate.

[Fenwoodian]

Conclusion: The mega pixel count is secondary for printing, but the lens and optimal post processing is critical. Sufficient dynamic range is get the most out of image post processing.

Why not have all three (mega pixels, lens, AND optimal processing)? If one can afford it, capturing optimum number and quality of pixels opens up all sorts of options to the serious photographer.

As for optimal post processing... It takes me lots of time to properly post process my images for printing. I rarely do it these days, instead, I archive my best images for latter post processing and printing in future years.