[Bob 256]

Can you try your photo several different ways on less expensive media and then judge the results? That might be the way to go before committing to the final print. It might not be a good way to judge color but you can settle resolution questions that way.


I too would recommend sticking with the native resolution of the printer used so an extra interpolation step isn't introduced using who knows what algorithm.

[The Squirrel Mafia]

My K-50 spits out 4928x3264 sized images. I have very good looking 30x45 low ISO prints (100-400) hanging from my wall. That amounts to about a 109dpi print.

Your K-3 spits out 6016x4000 sized images. You could easily do a 40x60 print that looks good. That would approximate to a 100dpi print. At a reasonable viewing distance, it'll look pretty darn good.

Basically, divide the image size by the paper size & you get the idea, but as the ISO climbs, then you start to lose resolution & noise becomes a factor. I do have a very good looking B&W 24x36 ISO 6400 print out of my K-50 that I post processed. It's slightly grainy, but in a pleasant looking way.

But yeah. The smaller you print, the "better" it looks. As your prints get larger, they will show more flaws.

[promacjoe]

Let me see if I can shed some lighton the subject,300 DPI is equal to 0.003333 Per Dot. I measured a new stack of 500 sheets of computer paper. It measured 1.968". This gave an average of .003936" . On a 200 per inch image, each.will measure .005" . the question is, can you tell the difference between an image printed at 300 dots per inch compared to 200 dots per inch, in the location that your intended to put it.

As a comparison, I have made 11x14 prints, from a 6 megapixel, 3000x2000, Image. That's 181 DPI. and you could not see any loss in quality even at close up. remember, were talking about a dot that is 0.001037" larger than the thickness of a piece of computer paper, (300DPI). you be the judge.

[joergens.mi]

it may be usefull, to scale the picture for the print exactly to size, with the resolution of the printer, than there is no interpolation by the printer software. (but this is only usefull when you are a pixel perfectionist.)

[TonyW]

Let me see if I can shed some lighton the subject,300 DPI is equal to 0.003333 Per Dot. I measured a new stack of 500 sheets of computer paper. It measured 1.968". This gave an average of .003936" . On a 200 per inch image, each.will measure .005" . the question is, can you tell the difference between an image printed at 300 dots per inch compared to 200 dots per inch, in the location that your intended to put it.

As a comparison, I have made 11x14 prints, from a 6 megapixel, 3000x2000, Image. That's 181 DPI. and you could not see any loss in quality even at close up. remember, were talking about a dot that is 0.001037" larger than the thickness of a piece of computer paper, (300DPI). you be the judge.

You are seemingly confusing DPI with PPI they are quite different and not really interchangeable.

DPI (droplets per inch) in printer terms is a measure of volume (not size) in picolitres, and is also variable volume with printers spraying somewhere between 1.5 - 4 picolitres (an incredibly small volume!). The final size that the droplet occupies varies on the amount laid down, the paper type absorption and spread characteristics and the print quality settings.
Looking at printer quoted DPI refers to how many droplets ink sprayed and this will be a multiple of the printers actual PPI resolution. Therefore a Canon printer 300 ppi required resolution could have as many as 8 individual droplets of ink sprayed when driver set to high quality @ 2400 dpi - Epson would be multiples of 360 ppi, so in this case print quality would be around 2880 dpi

PPI (Pixels Per Inch) on the other hand is a measure of size once declared from the native file resolution. This PPI measurement is also a measure of quality as it is the amount of data the printer requires to produce a print with optimal quality, which in turn depends on the quality of the acquired data.

Regardless of what you may think you are sending to the printer your data will be sent at the printers declared PPI requirements 300/360 Canon Epson respectively. So really your sending data at 181 ppi via the print driver will be upsampled to 300 ppi (Canon/HP) regardless, but the optimal quality will be achieved by resampling in LR, PS or even better a dedicated program such as Qimage.

It is possible that the gains in IQ may not be noticeable for a number of reasons including poor original data, subject matter, proper viewing distance or any other factor. But where the subject matter and the original IQ is first class it can and does improve IQ to enable viewing of fine detail at closer than normal distances

---------- Post added 06-20-17 at 12:16 PM ----------

it may be usefull, to scale the picture for the print exactly to size, with the resolution of the printer, than there is no interpolation by the printer software. (but this is only usefull when you are a pixel perfectionist.)

Not really, as this limits you to a fixed print size.

In many cases we want larger or smaller prints than the printers required ppi dictates so we have to rely on interpolation and the best interpolation algorithms will not be found in the print driver or OS but in third party such as Qimage, LR or PS.

Assume a Canon printer 300/600 ppi.
If we want a print 'x' size and we have only 200 ppi rather than allow print driver to upsample to 300 ppi we should do this in our application of choice.
For a print of 'x' size where we have in excess of printers lower requirements let's say 400 ppi then we should upsample to printers fine setting of 600 ppi

This has nothing to do with pixel peeping but all to do with maximising print IQ and not leaving it behind on the Lightroom floor. Whether you notice it or not depends on subject and the quality if the acquired image.

This subject mentioned briefly
https://www.pentaxforums.com/forums/32-digital-processing-software-printing/...r-best-iq.html

[joergens.mi]

Not really, as this limits you to a fixed print size.

In many cases we want larger or smaller prints than the printers required ppi dictates so we have to rely on interpolation and the best interpolation algorithms will not be found in the print driver or OS but in third party such as Qimage, LR or PS.

But his is exactly what I meant.
If the printer as a native resolution of 300 dpi (not droplets) than you'll get the best output if you send to the printer a file which has 300 dpi, and yes this restricts me to exactly one picturesize.
This scaling is done exactly for this print output, when there is a need for another different sized picture, i'll scale it to that size. This is not the processed picture which i store, this is an intermediate file for that print, with all modifications needed to optimize it for the printer an paper. The step in which way the printer generates the exact combination of droplets for the 3,4,5 (RGB, Grey, Black) colors from from 300dpi input is internal to the printer.

[normhead]

.
I continually make my own LARGE prints. The key is to send images to your printer that are exact divisibles of the print head resolution. I'm surprised that no one has mentioned this yet.

300ppi is not a universal truth - it's nothing more than an over-simplied generalization that has been perpetuated by the uninformed. For example, my large format Epson printer prefers 180, 240, 288 and 360. Sent it anything else and it will interpolate your file (not a good thing). For example, my printer will do a better job printing 288ppi files than 300ppi files.

For more info check this out...

+1...

I always talk to my printer and find out what the native resolution of the printer is. ON my Canon pro 9000 it was 300 DPI. The service I use now uses 360 DPI.

Before sending the file off to the printer , use Photoshop or in my case Pixelmator to enlarge the file. I may be at 220 DPI. It doesn't matter, enlarge the file to 360 DPI (or 300 DPI) at the size you want , in this case 20x30. It's generally better at least with Canon printers to bump your files to 300 DPI because their absolute finest pixel size kicks in at 300 DPI. You will get some improvement in your image by doing this. The vector based enlarging algorithms will clean up the messier parts of your image if there are any. And curves will be spread over more pixels making them more fluid. I once blew up a test chart that I'd printed myself to show that you got more detail with a longer lens and TC than just using the lens and enlarging it. The enlarged image looked better. Because the enlarging algorithm cleaned up the tiny ink smudges left by my printer. But the lens and TC un-enlarged reproduced them perfectly. The enlarged image looked better, but the un-enlarged showed what was actually there. So don't be afraid to create a 24 MP file from a 16 MP file or whatever. It often looks better.

But, you have to know what the optimum DPI of your printer is. My printer, Cavalcade Photo Source has a phone number for their print department, hopefully yours does too. Phone your guy and talk to him.

And listen to anything TonyW says.

[TonyW]

But his is exactly what I meant.
If the printer as a native resolution of 300 dpi (not droplets) than you'll get the best output if you send to the printer a file which has 300 dpi, and yes this restricts me to exactly one picturesize.
This scaling is done exactly for this print output, when there is a need for another different sized picture, i'll scale it to that size. This is not the processed picture which i store, this is an intermediate file for that print, with all modifications needed to optimize it for the printer an paper. The step in which way the printer generates the exact combination of droplets for the 3,4,5 (RGB, Grey, Black) colors from from 300dpi input is internal to the printer.

You can send the printer image information in PPI only not DPI! DPI is not a size measurement (since the demise of dot matrix printers) but a variable measure of volume of liquid.

The magic native resolution figure is not DPI but PPI, and PPI is not a measure of size until it is declared relating to the native file size. That is you can send a file with 'x' amount of pixels scaled at 300 or 600 ppi the choice will govern your final print size.

There are no imaging applications such as LR PS or Qimage or RIP's that know about DPI as the measurements are made in PPI.

The step that the printer generates can be internal to the printer but as pointed out this is not optimal for IQ

[boriscleto]

Okay I'm trying On1 Perfect Resize 10 right now and I have to say I'm really impressed with the results. It's even better than the algorithm offered in ACDsee Ultimate Clear IQZ algo (which isn't half bad itself).
It's crazy how the result stands to scrutiny. I'm pixel peeping at max resolution on my monitor and can barely see any artifact.
I think I'm going to go with this one. The free trial lasts 60 days. If I still need it after that I'll think about buying it. It's a bit expensive for a software that does just one thing though, especially if you're an amateur like me.

If anybody is interested, I downloaded from here. It includes the free trial which I didn't find any mention of on the official website.

$80 for On1 Resize 10 is crazy. You can get the whole PhotoRaw suite for $120. And the standalone Resize is the previous version...

I paid for On1 Perfect Suite 9, and they gave me a free upgrade to Photo 10.5 when they cut off support for 9.

[joergens.mi]

Just for information:

From epson printers:
Epson Expression Premium XP-640 Small-in-One All-in-One Printer | Inkjet | Printers | For Home | Epson US

Printing Technology:
5 ink cartridges (CMYK, Photo Black), drop-on-demand technology MicroPiezo® inkjet technology
Minimum Ink Droplet Size:
5 ink droplet sizes, as small as 1.5 picoliters.
Maximum Print Resolution:
5760 x 1440 optimized dpi


Canon:
Technische Daten - Canon Deutschland
Druckauflösung

bis zu 9.600 x 2.400 dpi ( Tintentröpfchen werden in einem Raster von 1/9.600 Zoll platziert. )

Sorry for german: I'll translate

up to 9600x 2400 dpi (droplets are placed in a grid of 1 / 9,600 inches)

The defacto name is dpi and is the definition of the grid to place an amount of droplets in.

May be that you are right in an academic way of definition. But we should work with the "de facto standard" - that most of the people will understand - not with some academic de jure standards (you should be used to, look at feet, inch or Fahrenheit instead of MKSI International Units)

[promacjoe]

You are seemingly confusing DPI with PPI they are quite different and not really interchangeable.

DPI (droplets per inch) in printer terms is a measure of volume (not size) in picolitres, and is also variable volume with printers spraying somewhere between 1.5 - 4 picolitres (an incredibly small volume!). The final size that the droplet occupies varies on the amount laid down, the paper type absorption and spread characteristics and the print quality settings.
---- Post added 06-20-17 at 12:16 PM ----------

No, you are confused. I did not mean droplets per inch. I met dots per inch. This is a more generic term. To my knowledge, droplets per inch is only used for inkjet printers. It does not apply to the laser process or any other printing processes. Since I do not know the exact process being used, I used a generic term. And I used it to describe the size of each./group of colors that will be printed. which may not be discernible to the human eye given the Viewing distance.

[TonyW]

Just for information:

From epson printers:
Epson Expression Premium XP-640 Small-in-One All-in-One Printer | Inkjet | Printers | For Home | Epson US

Printing Technology:
5 ink cartridges (CMYK, Photo Black), drop-on-demand technology MicroPiezo® inkjet technology
Minimum Ink Droplet Size:
5 ink droplet sizes, as small as 1.5 picoliters.
Maximum Print Resolution:
5760 x 1440 optimized dpi


Canon:
Technische Daten - Canon Deutschland
Druckauflösung

bis zu 9.600 x 2.400 dpi ( Tintentröpfchen werden in einem Raster von 1/9.600 Zoll platziert. )

Sorry for german: I'll translate

up to 9600x 2400 dpi (droplets are placed in a grid of 1 / 9,600 inches)

The defacto name is dpi and is the definition of the grid to place an amount of droplets in.

May be that you are right in an academic way of definition. But we should work with the "de facto standard" - that most of the people will understand - not with some academic de jure standards (you should be used to, look at feet, inch or Fahrenheit instead of MKSI International Units)

No, I am sorry but you do not seem to understand the de facto standard is both PPI and DPI and most people need to understand this and don't. As Jeff Schewe said in his introduction to this very subject "most people do not have a clue about resolution"

A printer has two resolutions the first being the Input Resolution this is a measure of what the device expects in Pixels Per Inch. This is the figure that is declared to the OS and demanded by the printer for it to produce a print of a specific size. This is a very important aspect of printing as it is a control of the final print size and of input quality.

The second resolution is the DPI (droplets per inch) which is the Output Resolutionand as you quoted Epson Maximum Print Resolution: 5760 x 1440 optimized dpi.
This figure refers to the number of ink droplets that can be laid down to represent a single pixel and once again is a measure of volume not size and ink will be laid on top of each other to give the impression of different colour and up to a degree small resolution improvement

The resolution that is most important to image IQ is really the input resolution i.e. the PPI as this controls what we really see as fine detail. The output resolution (putting more or less ink on the paper) is not as important.

Perhaps it may be of general interest to see what Epson themselves had to say about these aspects of printing in a White Paper produced in 2008

Jaggies
What are Jaggies?
"Jaggies" are stair like lines or curves that appear where there should be smooth straight lines or curves.

These "jaggies" may appear (the visibility is dependent on the actual image content) when the image input resolution is not a direct multiple or half the native print head resolution.

In fact the "jaggies" are nearest neighbour interpolation artefacts.

When sending an image file to the printer, the printer driver will convert the image file to its own proprietary bitmap file before printing starts
If the image resolution is not a direct multiple or half of the printers native resolution the conversion will create interpolation artefacts.

The highlighted text (mine) points to the fact that the print driver interpolation based on nearest neighbour a fast but not the best from an IQ perspective, hence the recommendations to upsample via your editing application rather than rely on print driver

Due to the nozzle spacing on the print head, the Epson inkjet print heads have a native resolution of 360 dpi. Therefore any image input resolution that is exactly 360 ppi or a direct multiple or half of it produces images without "jaggies" on lines or fonts and the best sharpness of details.

And this is the reason why we should be be concerned about the resampling to 360/720 Epson or 300/600 Canon

[Fenwoodian]

No, I am sorry but you do not seem to understand the de facto standard is both PPI and DPI and most people need to understand this and don't. As Jeff Schewe said in his introduction to this very subject "most people do not have a clue about resolution"

A printer has two resolutions the first being the Input Resolution this is a measure of what the device expects in Pixels Per Inch. This is the figure that is declared to the OS and demanded by the printer for it to produce a print of a specific size. This is a very important aspect of printing as it is a control of the final print size and of input quality.

The second resolution is the DPI (droplets per inch) which is the Output Resolutionand as you quoted Epson Maximum Print Resolution: 5760 x 1440 optimized dpi.
This figure refers to the number of ink droplets that can be laid down to represent a single pixel and once again is a measure of volume not size and ink will be laid on top of each other to give the impression of different colour and up to a degree.

The resolution that is most important to image IQ is really the input resolution i.e. the PPI as this controls what we really see as fine detail. The output resolution (putting more or less ink on the paper) is not as important.

Perhaps it may be of general interest to see what Epson themselves had to say about these aspects of printing in a White Paper produced in 2008

[/I]The highlighted text (mine) points to the fact that the print driver interpolation based on nearest neighbour a fast but not the best from an IQ perspective, hence the recommendations to upsample via your editing application rather than rely on print driver

And this is the reason why we should be be concerned about the resampling to 360/720 Epson or 300/600 Canon

'.

.

Tony, thank you for taking the time to explain in such great detail these important (and often misunderstood) principles of optimizing results from ink jet printers.

[fehknt]

If you're printing at a lab; particularly on substrates like metal and acrylic, there's really nothing for it but to order the smallest possible print with a crop of your processed-for-print image that will be the correct size. E.g., print 6x6 when you intend to print 12x36 and just have a small square crop of your image that's half the height and 1/6 the width of the one you'll send to print. If you like it, great. If you want to look at it under magnification and complain to them about the print interpolation artifacting (assuming it exists and the lab doesn't already do the right thing in their print pipeline) then most labs will accept a complaint and offer a re-print, ideally that will start a conversation with their support to let you optimize specifically for their print hardware if you so desire. Some interesting examples here: Inkjet Resolution

This thread has me curious now and I'll be looking at some of my stuff under magnification...

[TonyW]

Fenwoodian, you are most welcome and I hope it may be of some help for those wishing to maximise the IQ potential after spending huge amount of cash on cameras and lenses - it would be a shame to drop IQ due to not taking a little extra care in prep for prints at least that is my view.