Publisher: wrong size on export

[Vosje]

Hello,

I'm sorry if there is already a solution for this, I couldn't find it. I don't get something, when I create a document in Publisher and choose the size of my pages in mm and set it to, say 300 x 300 mm and then I have facing pages (a spread), if I then export my document as loose JPEG files... The final size of my exported JPEGs is not 600 x 300 mm as I would have expected, BUT 600 x 300,1 mm. Where does this extra 0,1 mm come from??? How do I get rid of it? Why doesn't Affinity export to exact the same size as specified in my document setting? I have NO bleed in my document, my document has 300 dpi and I also export to 300 dpi.

Thanks in advance!

[thomaso]

52 minutes ago, Vosje said:

Where does this extra 1 mm come from?

This seems to be due to the rounding of decimal fractions of pixels with Affinity export versus units such as millimetres or points. Unfortunately it is a known issue for years and appears still unavoidable in Affinity. It is especially problematic if an automated print pre-press process rejects PDF because of exceeded page sizes.

[Vosje]

54 minutes ago, thomaso said:

This seems to be due to the rounding of decimal fractions of pixels with Affinity export versus units such as millimetres or points. Unfortunately it is a known issue for years and appears still unavoidable in Affinity. It is especially problematic if an automated print pre-press process rejects PDF because of exceeded page sizes.

Hi @thomaso, thank you very much for your reply. This is kind of really stupid, I mean, it's just weird that a program fails to export a file using the chosen settings, I even have to say it's kind of unacceptable that a document you create gets an additional 0,1 mm and there's nothing that can be done about it!

[loukash]

1 hour ago, thomaso said:

Unfortunately it is a known issue for years and appears still unavoidable in Affinity.

It's unavoidable in any apps that need to convert from metric units to the pixel domain:
1 px = 1 pt @ 72 ppi, and 1 pt = 0.352778 mm

Similarly, a DIN A4 PDF will never be exactly 210.000000 × 297.000000 mm.
Affinity attempts to round to full pixels as it seems.
Even an exported DIN A4 PDF from InDesign will not be exact 210.000000 × 297.000000 mm, even though ID has handled the metric system pretty well, unlike Illustrator.

11 minutes ago, Vosje said:

it's kind of unacceptable that a document you create gets an additional 0,1 mm and there's nothing that can be done about it!

Haha, I hear you. That's why I used to nickname Illustrator "Ill-Frustrator".
Affinity is actually more predictable here.

If you need mm precise dimensions of a bitmap image, you must increase the ppi resolution.
That's why e.g. for precise bitmap graphics you would use resolutions of at least 1200 ppi.

[Vosje]

Thans for your tip, @loukash! But other programs do manage to produce a correct result (see the link that @thomaso provided)... So, it *IS* possible to have correct document dimensions... Also, Affinity could have at least try to fix their own standard presets (as in, tell the program to round the other way when using DIN sizes... that would not have solved the problem of custom created sizes if that's so difficult, but since DIN sizes are widely used it would have halped a lot already). Sigh.

[loukash]

Fair enough, there might be some miscalculation "lost in unit conversion" in Affinity. I'll read that thread later in detail.

However, it's not "0.1" mm.
If you export a DIN A4 PDF @ 300 ppi from Publisher, it will be exactly 210.058 mm = 2481 px wide. 
Whereas 2480 px = 209.973333 mm. That's not bad either, but it's ultimately less than what we want.
My "half-educated" guess is that Affinity always attempts to round up to full pixels rather than round down. Because you can always remove/crop that extra pixel if needed, but not vice versa…

P.S. to actually see exact values, you must set Preferences > User Interface > Decimal Places to "6"

Edited December 9, 2022 by loukash

[loukash]

One more thought on accurate page sizes though:
Given that crop marks alone are usually 0.25 pt = 0.09 mm, in the print domain (where else would you want to use metric units?) a difference of 0.1 mm is usually negligible.

3 hours ago, Vosje said:

create a document in Publisher and choose the size of my pages in mm and set it to, say 300 x 300 mm and then I have facing pages (a spread), if I then export my document as loose JPEG files... The final size of my exported JPEGs is not 600 x 300 mm as I would have expected, BUT 600 x 300,1 mm.

I have now tested this exact scenario you're describing.

I can't see anything wrong with it.
It is exactly as I have described above: Rather than cutting a pixel off, Affinity rounds up to the next full pixel based on document resolution. Hence when you place the exported "600×300" mm (rounded up to full pixels = 7087×3544 px) back on your exact 600×300 mm spread, the image will slightly overlap at 100 % size. That's a Good Thing™ in my book. In the bitmap domain, only an integer amount of pixels can exist.

The pale green lines are my custom pixel grid of the spread to illustrate that 600×300 mm ≠ integer amount of pixels.

[loukash]

For what it's worth, I have now set up the exact same 600×300 mm spread in InDesign CS5.5 and exported as JPEG.
Ther result is actually worse because ID rounds the height down to full pixel, i.e. the exported JPEG is only 7087×3543 px.

[thomaso]

1 hour ago, loukash said:

the exact same 600×300 mm spread in InDesign CS5.5 and exported as JPEG.
Ther result is actually worse (…) the exported JPEG is only 7087×3543 px

I get 7087 x 3544 px from CS6.

While the export size of a pixel image in APub can alternatively be set in pixels (instead of mm), a resulting PDF in APub appears "actually worse" while ID exports with the set & wanted mm dimensions:

 

[loukash]

2 minutes ago, thomaso said:

I get 7087 x 3544 px from CS6.

That must have been definitely worth the upgrade price of… €400 or so…?  

[thomaso]

12 minutes ago, loukash said:

worth the upgrade price

interesting aspect in this thread of one of several long lasting bugs 😇

[Vosje]

2 hours ago, loukash said:

One more thought on accurate page sizes though:
Given that crop marks alone are usually 0.25 pt = 0.09 mm, in the print domain (where else would you want to use metric units?) a difference of 0.1 mm is usually negligible.

I have now tested this exact scenario you're describing.

I can't see anything wrong with it.
It is exactly as I have described above: Rather than cutting a pixel off, Affinity rounds up to the next full pixel based on document resolution. Hence when you place the exported "600×300" mm (rounded up to full pixels = 7087×3544 px) back on your exact 600×300 mm spread, the image will slightly overlap at 100 % size. That's a Good Thing™ in my book. In the bitmap domain, only an integer amount of pixels can exist.

Wow, thanks a lot for your work! I can see your point now in that if you need to somehow use the exported result in your workflow again it's good that they round the pixels up to give you 100% coverage.

However, the JPEGs were required to be sent to a printer - this is the way they wanted them, not a PDF or anything - and while I agree that a difference of 0,1 mm is not much, it also doesn't comply with the required size of 60 x 30 cm. So, maybe for some situations it doesn't matter, while for others it may.

The way I see it, if I as a user decide to use a certain metric system, be it pixels, mm, cm, inches or whatever and specify my document to be EXACTLY that size, I expect my export to be EXACTLY of that very size in those units. So, if I want 300 mm, I want 300 mm on export. And it doesn't matter to me that much whether it's 3544 or 3543 px. 🤔

[loukash]

4 minutes ago, thomaso said:

in this thread of one of several long lasting bugs

JPEG export being rounded to full pixels is not a bug.
Seriously, I don't know how else would you want to export a bitmap image of a layout that is based on metric units…

As for the PDF issue, maybe, but that's not the subject of this thread, as far as I can tell.  

1 minute ago, Vosje said:

it also doesn't comply with the required size of 60 x 30 cm

7 minutes ago, Vosje said:

if I want 300 mm, I want 300 mm on export

If you want your 600×300 mm JPEG to be exactly 600 mm wide, don't export at 300 ppi.
600.000000 mm = 23.622047 in ≈ 7087 px @ ±300 ppi
7087/23.622047 = 300.016 ppi
or:
7086/23.622047 = 299.974 ppi

That's how the math works on this side of the Universe As We Experience It™  and its physical laws…  

[Vosje]

8 minutes ago, loukash said:

If you want your 600×300 mm JPEG to be exactly 600 mm wide, don't export at 300 ppi.
600.000000 mm = 23.622047 in ≈ 7087 px @ ±300 ppi
7087/23.622047 = 300.016 ppi
or:
7086/23.622047 = 299.974 ppi

That's how the math works on this side of the Universe As We Experience It™  and its physical laws…  

But what if you're told to deliver an image of 600 x 300 mm at 300 dpi? For me, maybe it wouldn't matter, but if the printer tells you to give them something with certain specifications and you can't, that can *potentially* be a problem (especially if your client demands it exactly that same way).

I mean, if other programs CAN, why can't Affinity?

[walt.farrell]

4 minutes ago, Vosje said:

But what if you're told to deliver an image of 600 x 300 mm at 300 dpi? For me, maybe it wouldn't matter, but if the printer tells you to give them something with certain specifications and you can't, that can *potentially* be a problem (especially if your client demands it exactly that same way).

I mean, if other programs CAN, why can't Affinity?

I may have missed it through careless reading, but what other program can produce a 600 x 300 mm raster document (JPG, TIFF, PNG) at 300 dpi? Can you share such a file with us, so we can examine it?

[loukash]

12 minutes ago, Vosje said:

But what if you're told to deliver an image of 600 x 300 mm at 300 dpi?

I'll tell them to repeat the 7th grade math lessons.  

12 minutes ago, Vosje said:

other programs CAN

As I have proven, InDesign can't either. There's no such thing as a "half pixel" in the bitmap domain. It's always full pixels.
If you need to connect the physical domain of the metric or imperial system to the virtual pixel domain, your calculation factor is pixel per inch or pixel per cm. That value doesn't need to be an integer.

An example while we speak:

Voilà. 
The green grid is still my aforementioned 1-px-grid.
Everything pixel- and mm-aligned.
When the ppi (aka "DPI" is Affinity jargon) matches!

[loukash]

10 minutes ago, walt.farrell said:

what other program can produce a 600 x 300 mm raster document (JPG, TIFF, PNG) at 300 dpi?

Sho'nuff Schmotophop will, right?

 

 

Oh, wait:

Bummer.

[Vosje]

Okay, maybe I don't get something, I seriously don't understand why it's not possible to create a file of 600 x 300 mm at 300 dpi... Here is a JPEG that I have just made (NOT using Affinity!) and even if I open it with Affinity and convert the units to mm (it shows them in pixels on opening), it will say that its dimensions are 600 x 300 mm at 300 dpi... But when I open the JPEGs that I made with Publisher (300 x 300 mm at 300 dpi setting) and convert the units to mm, it shows 600 x 300,1 mm! So, obviously, this empty JPEG that I attached to this post is the size that I would like Affinity to produce and somehow this image does exist having these dimensions, or am I wrong?

[MikeW]

7 minutes ago, Vosje said:

Okay, maybe I don't get something, I seriously don't understand why it's not possible to create a file of 600 x 300 mm at 300 dpi... Here is a JPEG that I have just made (NOT using Affinity!) and even if I open it with Affinity and convert the units to mm (it shows them in pixels on opening), it will say that its dimensions are 600 x 300 mm at 300 dpi... But when I open the JPEGs that I made with Publisher (300 x 300 mm at 300 dpi setting) and convert the units to mm, it shows 600 x 300,1 mm! So, obviously, this empty JPEG that I attached to this post is the size that I would like Affinity to produce and somehow this image does exist having these dimensions, or am I wrong?

You are wrong.

It is the size of the post above yours. With a couple more digits:

[Vosje]

4 minutes ago, MikeW said:

You are wrong.

It is the size of the post above yours. With a couple more digits:

Ok, thaks for the screenshot! I don't have Acrobat.

So, I guess, it just all depends on the settings of the application you're using to view your file (and how many decimals it shows and how it rounds them up).

As the difference is, of course, quite small, here's me hoping that nobody will make a problem out of this if the sizes they receive don't exactly match their requirements. 😆

[Old Bruce]

18 minutes ago, Vosje said:

Okay, maybe I don't get something, I seriously don't understand why it's not possible to create a file of 600 x 300 mm at 300 dpi...

It is arithmetic plus the fact that we cannot have a fraction of a Pixel (AKA as the d in dpi).

300 mm  = 11.81102362206 inches. And that means 3543.307086618 pixels. Note the decimals. We can't have that with TIFF, JPEG, PNG, GIF, etc.

Here is 300 mm with a pixel grid and the ruler set to pixels.

[Vosje]

Thanks a lot for your explanation, everybody!  I guess it would have been easier and more consistent if everybody just used pixels when specifying raster images' dimensions.

[walt.farrell]

1 hour ago, Vosje said:

Ok, thaks for the screenshot! I don't have Acrobat.

Here's what Photo 2 shows:

Note: Preferences, User Interface, will let you adjust the number of deccimal places that are displayed for the various kinds of unit measurements.

[thomaso]

35 minutes ago, Vosje said:

I guess it would have been easier and more consistent if everybody just used pixels when specifying raster images' dimensions.

Maybe you don't need everybody for this, it can even help if just you do it. That is why I mentioned before:

2 hours ago, thomaso said:

While the export size of a pixel image in APub can alternatively be set in pixels (instead of mm)

[Vosje]

5 minutes ago, thomaso said:

Maybe you don't need everybody for this, it can even help if just you do it. That is why I mentioned before:

While the export size of a pixel image in APub can alternatively be set in pixels (instead of mm)

Yes, that's right, but when other parties post required dimensions in mm or cm, there's no way of knowing how many pixels exactly that should be. But, that probably doesn't matter for most of things.