Publisher PDF Export Raster DPI over 400?

[AFY7]

I am working with a printer who prefers PDFs at 600 DPI. Affinity Publisher's drop-down menu for Raster DPI goes up to 400. However, you can manually enter 600. In this case, does Publisher really export the PDF at 600 DPI?

[lacerto]

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[lacerto]

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[AFY7]

Lagarto,

Thank you for the excellent information.

I am getting inconsistent messages from the printer. Now he is saying 400 DPI in the PDF is fine and that 600 DPI is the resolution in the actual factory print. I'll see how this all works out when I submit the file for his approval.

[sugr]

it does not. the resolution remains at 400 - that is my experierience

[walt.farrell]

1 hour ago, sugr said:

it does not. the resolution remains at 400 - that is my experierience

It does for me:

[lacerto]

For anyone interested, the behavior does not seem to have changed from 2019, so you can still override document and export default rasterization DPI values when exporting to PDF, in both directions (e.g. use 2400dpi rasterization in a publication that has 72 dpi document DPI, and vice versa). Unfortunately it still also applies that image layers (e.g. placed images with low placed PPI values) will be upsampled in certain situations (like when they have been cropped with Vector Crop Tool) to explicitly specified (or implied document) DPI without further notice. Already rasterized pixel layers are not touched unless they still have something to be resolved (like active FX effects applied).

I have not checked if there is an upper limit but e.g. 2400dpi can be typed in to override the highest list value (of 400dpi), and that value is then also used (if specified as the document DPI, this resolution will be used with on-canvas-rasterizations and also as the default for print-based PDF exports).

[R C-R]

2 hours ago, sugr said:

it does not. the resolution remains at 400 - that is my experierience

Can you post an example Affinity format file in which you have typed in a larger DPI value that does not allow exporting to that or higher resolution?

[sugr]

hi there. i am attaching 2 exported pdfs

1) where i "simply" changed the DPI in the export screen - this did not work. the dotted pattern is not at te required resolution - perhaps because of the downsampling-issue of the background dotted image. (the larger file)

2) when preparing the second pdf i did 2 things: 1) i set the document DPI at 1200 and i dismissed "resample images above 400dpi" the detailed export settings. that seem to have worked to keep the resolution of the pattern.

THANK you @lacerto

NcodePlainSeite10Task0000_1200DPI.pdf NcodePlainSeite10Task00001bis4.pdf

[lacerto]

You're welcome. Placed raster images (in image layers) can get both up and downsampled, and when presenting sharp edges like in your example, could get blurred depending on the chosen resampling method in the More options of the PDF Export dialog (the specified method is also used when upsampling, which is not obvious from the UI). The pattern can get distorted when downsampled and using "Nearest neighbor" resampling method (and also when upsampling when not simply duplicating the pixel dimensions).

To avoid resampling, downsampling can be prevented using the export options, and upsampling avoided by not cropping raster images with the Vector Crop tool or using a vector mask (clipping with a shape however is not a problem).

Oddly in Windows versions the maximum DPI that can be set in the More options box of the PDF Export dialog box is 1024 dpi, but the Export dialog itself seems to accept 3999 as the maximum value (on macOS 4000dpi). But generally there is no need to upsample hard edged raster images so the kinds of patterns used here typically stay hard edged even when using low-resolution bitmaps and when scaled up (which would then of course alter the pattern size and spacing). Basically the explicitly set document and export DPI is only used when flattening (rasterizing) effects that cannot stay as calculated effects (resulting also in affected vector objects and texts to become rasterized), placed raster images normally being scaled automatically and linearly only at final rasterization (using nearest neighbor resampling).

 

[R C-R]

7 hours ago, sugr said:

hi there. i am attaching 2 exported pdfs

What about attaching an example Affinity format file?

[RSI]

Hi!

I worked in a print shop (Germany) and it wasn't just a small print shop, but we also printed books and other projects. And we also always used 600 DPI for our printing plates, or in the PDF export that was then used for the printing plates.

I don't understand why Affinity doesn't support 600 DPI as a setting! Every professional software supports 600 DPI! This is not professional for me if this is simply ignored!
Sorry, I bought Publisher because I thought Affinity was professional. But I guess I was wrong....

I have to export/convert my documents to 600 DPI every time now, because the Publisher did not save a setting of 600 DPI. Direct printing to a printer with 600 DPI is therefore not possible at all! Very bad... I am quite disappointed with this software!

[joe_l]

6 hours ago, RSI said:

I have to export/convert my documents to 600 DPI every time now, because the Publisher did not save a setting of 600 DPI.

? Set up your document with 600 dpi first and you are good to go. Or make templates with 600 dpi.

[lacerto]

You can also set ad-hoc DPI for rasterized objects at print time, so that objects that need to be pre-rasterized will be rendered at the specified resolution (instead of using the document resolution). Below a vector based job where document DPI is 300dpi is forced to be rasterized first at 1200 dpi, then at 20 dpi, and directed to .ps files, then opened in Photoshop to show the difference:

The file sizes directly show that ad-hoc DPI setting has an effect:

Vectors, shapes and text would typically be rasterized only on printer at the device's maximum resolution and placed images rendered at the specified resolution.