Resolution (Dpi) in print module

[RobEW]

Thank you all for such detailed replies and conversation.

The depth of knowledge is as impressive as the diversity of opinion.

A few observations:

• The user interface seems to provide just a few parameters to use. My initial question was about whether the dpi field should be used to describe the image file or the printer. It arose from the fact that when I hover my cursor over the field, there is no pop-up help, and when I peruse manuals and videos I don’t find much either.

• It seems some people here have huge swathes of theoretical knowledge and sophisticated mental models which they deploy to try to answer this question. Even with that level of knowledge there seems to be limited consensus.

• This conversation is made more difficult because people use terminology differently.

• Given the diversity of views and the various tangents, the conversation doesn’t really give a definitive authoritative answer to my question.

• It would be far better if DXO themselves provided a definitive response in their manuals or pop=up help. Then we would all know how to use the product, and if it didn’t work their would be a commercial / reputational obligation for them to fix it.

A good user interface can be used by someone without a huge level of theoretical knowledge and mental models. Just as you can drive a car without knowing about engines; all you need to know about is the controls - accelerator, brake etc. You don’t need to know how they work. You do need to know whether to put petrol or diesel in, but you don’t need to know how many cylinders it has. It would be nice if the print module of DXO Photoshop was like this. Life’s too short to learn all the internal workings.

[Joanna (Joanna Carter)]

Excellent!!! @George, this is where you set the printer resolution, not on the main dialog. This controls the print quality.

So, we can definitely say that “Resolution” on the main dialog has nothing to do with the printer resolution in dpi - it is inappropriately labeled as “dpi” when it should be “ppi”. In theory, you should be able to set this to any value. Can someone confirm this?

[George]

@Joanna

Once again, I must remind you that 1 pixel does not equate to 1 dot . 1 pixel has to equate to more than 1 dot in order to allow dots of more than one colour to fit within it (see pointillism).

In my opinion the different colors are laid at the same position. So 1 printer dot contains more droplets.

@Joanna

Resampling is only ever done at an image level, with pixels. Printer resolution plays absolutely no part whatever. If you want to increase the size of an image, you will always lose quality to a lesser or greater degree. You can either 1. double the number of pixels or 2. halve the ppi.

The result is equal. Dots and pixels are equal, only one is fysical and the other is not. When resampling an image I have different tools to do that out of which I can choose. But I think a main difference between an image and a print is, that I can view the image at 100% and edit it. A print is less sensitive.

George

[George]

@Joanna

So, we can definitely say that “Resolution” on the main dialog has nothing to do with the printer resolution in dpi - it is inappropriately labeled as “dpi” when it should be “ppi”. In theory, you should be able to set this to any value. Can someone confirm this?

Not in PL. There predefined paper sizes are used. The image resolution is calculated from that. You know, that print triangle
In Irfanview you can, there is also an option: print real size.

In PL the resolution is showing the active printer resolution. Though you can change the field, nothing happens. We are not the only one struggling with printers.

George

George

[Joanna (Joanna Carter)]

@George

In my opinion the different colors are laid at the same position . So 1 printer dot contains more droplets.

In your opinion maybe, but not in reality. If you take a strong loupe to an inkjet print, you will see that each dot has its own position. It is impossible for the inks to mix on the paper, they dry too quickly. Once again, see how pointillism works

[Joanna (Joanna Carter)]

@George

Not in PL. There predefined paper sizes are used. The image resolution is calculated from that. You know, that print triangle

OK. So now, instead of showing us the dialog from IrfanView, go to the print dialog in DPL, click on the “Printer properties…” button and take a screenshot of that to show us please?

[Joanna (Joanna Carter)]

@RobEW

A few observations:

• The user interface seems to provide just a few parameters to use. My initial question was about whether the dpi field should be used to describe the image file or the printer. It arose from the fact that when I hover my cursor over the field, there is no pop-up help, and when I peruse manuals and videos I don’t find much either.

It is definitely for setting the image resolution, not the printer’s

@RobEW

• It seems some people here have huge swathes of theoretical knowledge and sophisticated mental models which they deploy to try to answer this question. Even with that level of knowledge there seems to be limited consensus.
• This conversation is made more difficult because people use terminology differently.
• Given the diversity of views and the various tangents, the conversation doesn’t really give a definitive authoritative answer to my question.
• It would be far better if DXO themselves provided a definitive response in their manuals or pop=up help. Then we would all know how to use the product, and if it didn’t work their would be a commercial / reputational obligation for them to fix it.

Rob, you are right in so many ways. And it all stems from the fact that the DPL printer dialog is very poorly conceived when compared with other software. I would agree that DxO should take steps to update this dialog to make it less confusing and easier to understand/use.

Thank you for your initial question. Even though we seemed to take off at various tangents, it has been useful to air the subject. We can but hope that DxO can respond

[George]

I changed the resolution in pl to 75, papersize Nort America 3x5. I did get a print on A4 of 10x16.7, in the left bottom corner.
Changing to 300 dpi a same size but more to the middle. Idem with 5444. But then I saw something. The resoltion of 5444 just stay’s there but as soon as I hit the print buttom it changes to 1200.

[Joanna (Joanna Carter)]

Could we please see a screenshot of the dialog you are using?

[George]

[Joanna (Joanna Carter)]

OK. Now can you hit the “Printer properties…” button and give us a screen shot of that dialog?

[George]

It’s the printer dialog from the os/printer itself.

[platypus (Canon & Mac (Intel and M1))]

@RobEW

Is there any advice as to what value to select to get the best quality?

@RobEW, did you find the definitive answer in this longish thread?

If yes, what is your take away?

[Joanna (Joanna Carter)]

@George

It’s the printer dialog from the os/printer itself.

Correct. and this is where you should be able to set the printer resolution.

Now let’s see a screenshot of what’s on the Eigenschappen tab

[OXiDant (Peter)]

@Joanna

Can someone confirm this?

ok what i can do for you:
i print a 50dpi ,100dpi and a 200dpi and 300dpi and 600dpi in file and stick this in a printer when i am working again over 1 week.
edit: (i can’t after close examination: i can’t print to file, create a printerfile.prn which i can set on a usb and print directly in the usb of the printer. like this:

or this:

DxO hassn’t build in this function.

(And forgot this one:
for overrulling the calibration of the printer:

i made e export of 1 image in 72ppi/100/300/600ppi non resampling and resampling.
the non shows no difference:

(let’s see if next week my printer reads “properties” (don’t think so.)
next the allow resampling by dxo.

The value of ppi does totally NOTHING on a viewing screen.

only thing what does some action is “longest size”

when i use the printer version:
Then it does some thing:

600ppi non resampled

resampled to 600ppi

72ppi non resampled:

72ppi resampled:

By the way because i always let the printer sort it out and not the export of the application this is new for me to see what effect’s it holds.
video: test of 600ppi and 600ppirs and 72ppi
it seems to define how many pixels it uses to define 1 dot. (that’s why 600ppi resampled is such a small image)

finally the PPI setting is “how much Pixels i may use to define 1 dot!”
i don’t print much in this way, most i do is view on screen.

(i am very curious if my printer does anything with this “resolution set to 300 ppi” thing.)

[RobEW]

Thanks for asking. I can’t claim to have followed or understood everything which has been said. My take-away an hour ago was summarised here Resolution (Dpi) in print module

To summarise, my main takeaways were that it’s really complex, above most people’s heads, even experts don’t agree, and so DXO ought to document how to use the field and then if necessary make their software match their documentation.

Joanna kindly replied with some clarification - the “Resolution” field (she says) definitely refers to the image file and not to the printer. (So my next question is this: Why can’t Photolab determine this without my having to repeat it? )

[George]

I’m running out of names!
With this hp-printer the max dpi is linked to certain papers. There’s no specific field for that setting. High dpi is 1200.

George

[Joanna (Joanna Carter)]

@RobEW

Joanna kindly replied with some clarification - the “Resolution” field (she says) definitely refers to the image file and not to the printer. (So my next question is this: Why can’t Photolab determine this without my having to repeat it? )

Because the resolution of an image file is a movable feast. It depends on what you want to display it or print it on. An image file has, in itself, no inherent resolution - the number often depends on the software you use to open it.

If you take an image file out of a full-frame digital camera, the “inherent” resolution is going to be (roughly) the number of pixels on the short edge, because it is 24mm (almost one inch). On an APS-C camera, the resolution will be based on the number of pixels on the long edge (assuming 36x24 and 24x16 proportions)

My Nikon D810 works out at around 5000 ppi, give or take a mm.

As soon as I put it on my computer, the short side, displayed at 100%, comes out at around 57 inches on (and off) my screen. That is some magnification and, no guesses, we are starting to see pixels.

Of course, the file size is quite big (76.5 Mb) and, so, for posting on a typical web forum, I would tend to export the file at 72 ppi with a pixel size of 1536 x 1024. This is a compromise between quality and file size and would not be printable, unless you only wanted a print at 6.4" x 4.3"

However, without resizing or resampling, I can print the same image, full size, at 240 ppi, as large as 30.7" x 20.5" - this would require an A1 printer and would still look good when viewed from as close as arm’s length.

So,

@RobEW

Why can’t Photolab determine this without my having to repeat it?

The answer is, what do you want to do with the image - web forum or an A0 (or bigger) print?

[platypus (Canon & Mac (Intel and M1))]

@RobEW

my main takeaways were that it’s really complex, above most people’s heads, even experts don’t agree, and so DXO ought to document how to use the field and then if necessary make their software match their documentation.

I get the same feelings regarding DPL printing. I’ve not used it a lot and I’ll probably stick to what has worked well for me so far: Lightroom

[Joanna (Joanna Carter)]

@platypus

I get the same feelings regarding DPL printing. I’ve not used it a lot and I’ll probably stick to what has worked well for me so far: Lightroom

Other printing utilities (some free) are available