Why set Publisher document at 300 ppi? Not as stupid a question as it sounds.....

[Chris26]

After all these years it suddenly dawned on me like a bolt of blue lightening while I was contemplating the meaning of the universe.....why does a publisher document have this setting in the first place?  Why not set it to 2 ppi?  

My images range from 180, to 240, to 300 and even 360 ppi.  I bring them in and they are there at their wonderful resolution very happy to take their place in the meaning of life.  Now what?  I print them out - at their resolution.  So what on earth is the point in setting a publisher document to 300, it surely never overides your image resolutions right?  Or am I going to be dissappointed with the answer?

Chris (No, I have not drunk any vintage port)

[GarryP]

I’ve always thought of the document resolution as a kind of ‘recommended target’ for printing/exporting.

In other words, I should try and get the individual image resolutions – as placed on the page – to be as near as possible to the document resolution so that they look like they have the same resolution in the final result – I think this makes the whole publication look nicer.

The software can do this for you automatically upon export but the result isn’t always as nice as I might want and it’s a reminder to me that it’s better for the resolutions of the images to be as similar as possible.

That’s probably not the best (or correct) answer, it’s just how I look at it.

[Pšenda]

But the document does not contain only images, but also text, curves and shapes that will be exported/printed in this resolution (that's why 300 DPI, which is the most common/standard printer resolution?)

[thomaso]

34 minutes ago, Pšenda said:

that will be exported/printed in this resolution (that's why 300 DPI, which is the most common/standard printer resolution?)

… and / or possibly get rasterised, @Chris26, wherefore they need to use a certain resolution to result in a sufficient amount of pixels.

In an .afpub set to 2 DPI an image of 10x10 inch would get 20x20 pixels only if rasterized.

Not to forget pixel creation in Affinity via brush strokes whose edges or textures should appear smooth, not pixelated.

Whereas there are use cases with a quite different DPI than 300. For instance large format prints, viewed of a large distance, may have 20 DPI only, while, vice versa, large formats layouted in scale, e.g. 1:100 need to get set to an accordingly higher document DPI because they get printed in 1000 % (=upscaled / e.g. 200 document DPI -> 1000 % print -> results in a 20 DPI print).

[thomaso]

P.S.: 300 DPI/PPI is a value similar to the human's eye resolution ability at a 'normal' reading distance (~10 inch).

At 300 DPI we don't notice raster dots in well printed media. As we don't notice a major difference in a rasterized 300 dpi print vs. a photographic reproduction with light (no raster).

[Oufti]

If 300 ppi is a correct resolution for an image in continuous tone (grey levels or colors) which will be screened for printing, when a rasterised image is to be printed in solid black only (one-bit image) its resolution should be 1200 ppi minimum. 

 

This is notably important for comic books, where the text and black outlines should be rasterised @ 1200 dpi when color fillings can be set @ 300. 

[Compositor K]

I've wondered about this too. I've never seen any reason to suspect that it affected the output, at least to my one black-and-white laser printer. As Chris26 noted, a blanket output resolution setting for the app doesn't make much sense. Perhaps it refers to screen display. If so, it might affect the relation between, say, an a page on the screen at 100% and an actual printout of the page at 100%.

[thomaso]

9 minutes ago, Compositor K said:

If so, it might affect the relation between, say, an a page on the screen at 100% and an actual printout of the page at 100%.

… and in "Actual Size" or in "Pixel Size", not to mention "Fit" and "Width" etc. – That's why there are several zoom levels for an impression/idea of 100% … while only one in the menu says literally "100 %" and none says "original size". Depending on the monitor's hardware pixel size + its physical screen size + the document resolution a certain page size on screen can appear in same size at several of the various zoom level options.

Well, "actually" an APub page or document would not need a resolution (as a PDF has none or a pixel image doesn't need one) but during a layout workflow it can be helpful for instance when images get placed (automatically in a certain size) or when objects get rasterized (with/to the current document resolution).

[Chris26]

Time on my hands, so I thought I might add something - I do not find this irritating at all, but when it happens I do Tut, you know, raise my eyebrows and moan under my tongue.  I make my images in photoshop at exactly the same size and resolution that I want them in my Publisher book.  Usually 300, but sometimes 360 (which is the perfect resolution for many photos), sometimes I make them at 240 because it reduces file size and the image is just as good at 240 as it would be at 300.  Now then, into publisher it goes, and because my publisher is always set at 300 you can guess now why I constantlyTut.  I really do not think Publisher should take control, but maybe it is a good thing for some, I don't know.

[thomaso]

1 hour ago, Chris26 said:

I really do not think Publisher should take control

What size would you prefer / do you expect when placing images of same or different DPI in APub? – If the layout document resolution should not matter, what else would define the placed size – considering that a physical image dimension (inch, mm) always depends on a certain resolution and varies with it.

Do you miss something like a "fill page" option when placing images? At least in this case a Picture Frame may work well, and placed on the master page maybe ideally.

[Chris26]

1 hour ago, thomaso said:

What size would you prefer / do you expect when placing images of same or different DPI in APub? – If the layout document resolution should not matter, what else would define the placed size – considering that a physical image dimension (inch, mm) always depends on a certain resolution and varies with it.

My whole understanding about this is quite simple, though I have to entertain the thought that I may be wrong, nevertheless here it is, that ALL images that are placed into a document come with their own native resolution.  That that should be honoured goes without question.  A document does not need a resolution for text, so what else does one need to assign a resolution for to a blank page document? Text has never needed resolution, vector graphics do need a resolution, and photos, raster images all have their resolution already set within themselves.  Now this has always been my understanding.  So if I do indeed miss something in this logic then that's ok, what have I missed?

[thomaso]

46 minutes ago, Chris26 said:

A document does not need a resolution for text, so what else does one need to assign a resolution for to a blank page document?  Now this has always been mu understanding.  So if I do indeed miss something in this logic then that's ok, what have I missed?

If you copy/paste text on a layout without creating a text frame it gets placed with a certain font size (defined in the Defaults that are also used for [No Style]). So, text has a certain size defined … before you past any text. Whereas if you paste into a text frame or place a text document the font  size is defined there, again before you get the text in your layout. – A corresponding workflow and app behaviour for pasting or placing images would be to use Picture Frames and their property options "fit", "scale" etc.

46 minutes ago, Chris26 said:

ALL images that are placed into a document come with their own native resolution.

Yes, … while their displayed size opened in any app varies with the monitor resolution (the hardware pixel size and density AND the set 'software' resolution (which you can set independently below the monitor's hardware resolution). If APub wouldn't have a certain document resolution than a placed image still might get placed differently on various configurations, someone with a retina monitor (~144 dpi) would get it placed in another size than one with a 96 dpi or 72 dpi screen.

For instance Email or Text Editor apps often (always?) don't have a certain resolution and ignore the resolution of a placed image, so a placed image can appear a lot larger than expected – which can be annoying, too.

To me it feels as an advantage to get an image placed relative to the document resolution: its placed size indicates its available pixel dimensions. Thus an image you saved with 360 dpi gets placed larger than one you had saved with 240 dpi. If both would get placed in same size you might need to check their placed dpi and possibly need or want to reduce the size of the 240 dpi image, for instance if you are working on a photo book layout that you want to output in 300 or 360 dpi.

Whereas it can be disturbing if you layout e.g. a manual for print in 300 dpi for instance with many screenshots: They by default get placed smaller than wanted while you possibly would not mind or even would want to maintain their pixelized look as screenshots. In that case it could be useful to reduce the document DPI until all images were placed (in wanted larger size this way) and increase the document resolution for further editing or output to maintain a higher resolution for other non-vector content than these screenshots.

[thomaso]

21 hours ago, Chris26 said:

and photos, raster images all have their resolution already set within themselves. 

There seems to be a misunderstanding. While analogue film material or camera lenses are limited to a certain max. resolution (not set or defined but measured / judged as detail sharpness, e.g. with a "Siemens Star"), digital images have clearly defined pixel dimensions ("Megapixel") but are variable in their resolution (DPI) and even don't need to have one set but can leave it to the displaying or printing soft-/hardware to scale the image (and thus its pixel size & density) to a wanted or possible value.

Actually "pixel" is not a unit like "inch", "millimeter" or "litre": while the latter have each an unambiguous definition of their "true" size, the "pixel" does not. In terms of output size, "pixel" is equivalent to "piece" and is non-specific such as "sheet", "package" or "bottle" – as opposed to clearly defined units such as "ft²", "cubic inch", "pint" or "pound".

Same subject with different words:

[lepr]

On 8/1/2023 at 2:57 PM, Chris26 said:

Time on my hands, so I thought I might add something - I do not find this irritating at all, but when it happens I do Tut, you know, raise my eyebrows and moan under my tongue.  I make my images in photoshop at exactly the same size and resolution that I want them in my Publisher book.  Usually 300, but sometimes 360 (which is the perfect resolution for many photos), sometimes I make them at 240 because it reduces file size and the image is just as good at 240 as it would be at 300.  Now then, into publisher it goes, and because my publisher is always set at 300 you can guess now why I constantlyTut.  I really do not think Publisher should take control, but maybe it is a good thing for some, I don't know.

The user should have control, of course. Control of placement size could be via the receiving document's unit of measurement (physical versus pixel), as it already is when copying objects from one Affinity document and pasting into another Affinity document.

Should be happening:

• if the receiving Affinity document's unit of measurement is physical, such as mm or inch, then a placed image file should have its physical dimensions (the product of its pixel dimensions and its DPI) honoured
• if the receiving Affinity document's unit of measurement is pixel, then a placed image file should have its pixel dimensions honoured.

Actually happening:

• regardless of the receiving Affinity document's unit of measurement being physical or pixel, a placed image file always has its pixel dimensions honoured.

 

[thomaso]

How to get rid* of document resolution
*How to simulate the layout process in APub without a document resolution

1.  Detect the physical  DPI resolution of your setup:
    = Screen's width in number of pixels divided by screen's horizontal lengths in inch.

1.a. In case your screen / operating system has a resolution set different from the monitor's hardware resolution or uses a technology like Apple's "Retina" to increase the displayed resolution: Divide the result of 1. by this deviating factor.
(on my mac it is "2" for instance, thus screenshot files get auto-saved with/as 144 dpi)

2.  Use the resulting value as DPI value for your Affinity document resolution. (to me: 111 dpi)

-> Then more than the usual number of Affinity > View > Zoom level options display the layout in identical view size: 100 % = Actual Size = Pixel size.
(-> Working this way maybe unexpected uncomfortable and it needs to be considered on export, e.g. if 300 dpi are demanded by a print service provider)

[lepr]

On 7/17/2023 at 1:44 PM, Chris26 said:

So what on earth is the point in setting a publisher document to 300 [dpi]

Affinity apps are designed in such a way that an Affinity document must have a specified pixel density - the DPI (dots per inch, although PPI meaning pixels per inch is a more appropriate term) - in order to relate the document's size to the physical world.

The key concept to understand is Affinity's internal unit of measurement is pixel, regardless of the document unit of measurement.

When the document unit of measurement is physical, sizes are not actually defined in physical units such as mm or inch. Instead, the user interface presents conversions from the internal pixel quantities to physical measurements. Likewise, when the user inputs a physical measurement, the value is converted to a quantity of pixels for further calculations and/or storage in the document.

Such conversions between pixel and physical obviously require a specified density of pixels per physical distance. The document's DPI value specifies that pixel density.

 

[thomaso]

53 minutes ago, lepr said:

Should be happening:

• receiving Affinity document's unit of measurement physical, such as mm or inch - a placed image file should have its physical dimensions (the product of its pixel dimensions and its DPI) honoured
• receiving Affinity document's unit of measurement pixel - a placed image file should have its pixel dimensions honoured

Actually happening:

• Regardless of the receiving Affinity document's unit of measurement being physical or pixel, a placed image file always has its pixel dimensions honoured

It appears indeed confusing that Affinity distinguishes placed file's resolution settings by their file format – while an option for a user's choice would be easy to reduce such a possible confusion, especially if we consider that an .afdesign might contain a placed image in a lower resolution than its parent documents DPI and thus be insufficient anyway if placed in an .afpub with 300 dpi for instance.

Documents in container file formats (e.g. PDF, EPS, Affinity) get their own "Original DPI" respected when placed in Affinity …

… whereas for pixel file formats APub just ignores a saved "Original DPI" and simply interprets + states it to be generally 72 dpi instead. (… and places with the current document DPI)

[lepr]

1 hour ago, thomaso said:

or pixel file formats APub just ignores a saved "Original DPI" and simply interprets + states it to be generally 72 dpi instead

You are using v1.x. The correct "Original DPI" is reported in v2.2.

[Chris26]

My knowledge here is obviously needing a boost.  I have some black and white images where I need them to stay at the PPI I have set in Apple mac Photoshop.  I bring them over to my windows affinity publisher and my publisher has to be at 300 ppi because most of my other images are at that resolution.  That is good.  However my 600 ppi B/W images will be reduced to 300 ppi in pubisher.  Question:  when I export to pdf for sending away, so long as the pdf's downsampling is OFF then will the individual image resolutions (240, 300, 360, 600 is what I have) of my images be Honoured DESPITE or in spite of Publisher's 300 PPI setting?  If I can clear this up then all is well.  Unfortunately the technicalities are hard to digest so if the answer is hidden aove somewhere sorry, I missed it. Thank you. 

[thomaso]

1 hour ago, Chris26 said:

Question:  when I export to pdf for sending away, so long as the pdf's downsampling is OFF then will the individual image resolutions (240, 300, 360, 600 is what I have) of my images be Honoured DESPITE or in spite of Publisher's 300 PPI setting? 

The answer is not "hidden above" because it concerns export options only and is regardless of the the aspects above (= does not concern placed images only but any content in the layout that got rasterized before or during export).

If downsampling is turned off the images will be exported accordingly (as expected) at their placed resolution (i.e. 600 dpi remains 600 dpi) – but may still be compressed differently than their original files.

I exported my CMYK .afpub as sRGB just to keep PDF size smaller and because colour was not the question here – BUT, interestingly this way pink sky artefacts occur in the PDF which are not visible in the layout view (though such pink in sky is reported in the forum quite a few times for RAW development in APh). So I added an export "as document" and, as before, without image colour conversion … which resulted in a PDF with no pink. For this export also compression was disabled and results in a the expected massively larger PDF file size than the two PDF with compression activated (apart from the different panel screenshots added to in the layout).

 v1105_on-300-20.pdf -  v1105_off-300-20.pdf -  v1105_off-300-off_as document.pdf

If you open the PDFs in Affinity you can check their different resolutions.

[Chris26]

4 hours ago, thomaso said:

The answer is not "hidden above" because it concerns export options only and is regardless of the the aspects above (= does not concern placed images only but any content in the layout that got rasterized before or during export).

If downsampling is turned off the images will be exported accordingly (as expected) at their placed resolution (i.e. 600 dpi remains 600 dpi) – but may still be compressed differently than their original files.

I exported my CMYK .afpub as sRGB just to keep PDF size smaller and because colour was not the question here – BUT, interestingly this way pink sky artefacts occur in the PDF which are not visible in the layout view (though such pink in sky is reported in the forum quite a few times for RAW development in APh). So I added an export "as document" and, as before, without image colour conversion … which resulted in a PDF with no pink. For this export also compression was disabled and results in a the expected massively larger PDF file size than the two PDF with compression activated (apart from the different panel screenshots added to in the layout).

 v1105_on-300-20.pdf -  v1105_off-300-20.pdf -  v1105_off-300-off_as document.pdf

If you open the PDFs in Affinity you can check their different resolutions.

 

So the conclusion is, colour aside, that affinity publisher's 300 dpi constraints have absolutely no effect at all on exporting a 600 ppi image to pdf with compression off.  In a twisted manner of seeing things, the document resolution is sort of a virtual reality thing to put it so crudely.  After all, if all your images are at whatever resolutions and you export them to pdf with compression off then that is what matters.

[thomaso]

1 hour ago, Chris26 said:

So the conclusion is, colour aside, that affinity publisher's 300 dpi constraints have absolutely no effect at all on exporting a 600 ppi image to pdf with compression off.  In a twisted manner of seeing things, the document resolution is sort of a virtual reality thing to put it so crudely.  After all, if all your images are at whatever resolutions and you export them to pdf with compression off then that is what matters.

Almost "yes": As hinted already in my last post, you need to distinguish between "Resampling" (down or up) and "Compression". The first gets used on export to adjust the image size (resolution), the latter is independent from any scaling or not-scaling and concerns the image quality (compression).

Compare once more: same resolution (300 dpi)  | different compression quality (10 vs. 98):  v1105 off-300-10_.pdf - v1105 off-300-98_.pdf
(this also reveals that the pink sky I mentioned above was/is a result of high compression)

The idea that DPI is just a virtual reality  meets my previous hints about "Pixel" not being a real "unit" but rather corresponding with "piece" instead. Again: DPI never describe a specific physical size alone, it always needs to know also the total number of pixels (e.g. horizontal) to be able to calculate the displayed size of a single pixel or the total width of all pixels of that image with a certain output condition (e.g. if printed in 100 %)

Accordingly, (and this was mentioned before in this thread) in APub a document resolution would not be required for images, like a PDF file has no resolution itself. In both files a resolution exists for included pixel content only and there it may vary between several objects (like the two images in my PDFs above have different DPI while the blank page or the text only have none / are independent of DPI). But in APub you can start with vector and get it rasterized to continue with other edits. For such rasterization a certain document resolution is used in APub. (… like, by the way, a specific DPI is also required in a PDF as soon you "flatten" all content in an existing PDF, e.g. transparency).

Fazit: On export the compression setting affects all images of an .afpub in the same way – whereas resolution depends on your resampling setting:: if OFF than the DPI of each placed image rules individually (600 and 300 and 100 for instance) and varies with the placed image sizes, whereas if set ON then the export setting rules (e.g. 300 for every single image).

[Oufti]

1 hour ago, thomaso said:

resolution depends on your resampling setting:: if OFF than the DPI of each placed image rules individually (600 and 300 and 100 for instance) and varies with the placed image sizes, whereas if set ON then the export setting rules (e.g. 300 for every single image).

To be extremely precise, resolution will be 300 dpi for every image which is ≥300 dpi (you apply only downsampling).

In your example, the images at 100 dpi will remain at 100 dpi. 

[Chris26]

3 hours ago, thomaso said:

Almost "yes": As hinted already in my last post, you need to distinguish between "Resampling" (down or up) and "Compression". The first gets used on

 Don't misunderstand me I know the differences, I do neither, ever, for export,  because all things are prepared exactly as I want them, so I do not want a third operator or software to mess with them.  My simple question from the beginning was - does publisher affect output resolution to pdf, that answer as I understand things is No, it does not.  Unless you tell the pdf to  downsample.  (leaving colour aside this is).

The only reason I am gtting to grips with PDF is because I have always been used to sending stuff as TIFF or PSD or JPEG, never in a pdf.  So now I have to make sure I understand how things work here.

 

[thomaso]

51 minutes ago, Oufti said:

To be extremely precise, resolution will be 300 dpi for every image which is ≥300 dpi (you apply only downsampling).

In your example, the images at 100 dpi will remain at 100 dpi. 

Ah, good point. In earlier versions APub used to be different and resampling on export did also upscale to fit to the set export resolution. Interesting and good to be aware of that Serif changed it meanwhile, like InDesign did upscale on export for many years and versions until they changed it (in the early 2000s / early CS versions).

Now I just noticed that there is a max. limit of 600 dpi for the Downsample setting (a typed value gets reset to 600), regardless of the current document resolution and of the set export resolution. This appears strange and can be disturbing for instance if you work in scale 1:10 (V2 makes such even easier). Then you might want for instance 1200 dpi for export to achieve a print result in 120 dpi. Then it appears weird if everything above 600 dpi would get downsampled, especially if the export resolution (e.g.  1200) is set above this upper downsample limit of 600 dpi.

Do you experience this "Downsample above" max. limit of 600 dpi in the Export dialog window of V2, too?