pdf image export BAD (Designer)

[Thomahawk]

Designer V2 mac monterey

Exporting a PDF that does include a qr code b/w image (see left sidein Designer), whatever I set in PDF export, even with PDF resolution set to 1200 dpi and no downsampling, the resulting PDF still includes the QR code in Low Res. (see image right side)

What else can be done?

[Thomahawk]

Even when I export a PDF, set 1200 dpi, or even set to not render and no jpg compression, the result was always the same Low Res QR code. This should not happen! In that case it should stay sharp like the image on the Designer artboard.

In afPhoto it showed the qr code was 22x22 pixel in size. The only solution was I changed the resolution to 2200x2200. But this should not be necessary when no rendering and no compression is done for the pdf export!

[joe_l]

1 minute ago, Thomahawk said:

In that case it should stay sharp like the image on the Designer artboard.

Could you upload a sample document here?

[Thomahawk]

sample with the original 22px image

sample.afdesign

[joe_l]

5 minutes ago, Thomahawk said:

sample with the original 22px image

Nothing wrong on my side with PDF Press-ready preset on Win 10. Could you post screenshots of your export dialogue?

[markw]

QR codes are coming out blurred for me to on Catalina. Could it be a Mac v Windows bug?

[joe_l]

3 minutes ago, markw said:

QR codes are coming out blurred for me to on Catalina.

What happens, when you rasterise the layer with the QR before export?

[markw]

Ah yes, that fixes it! But should that step really be necessary?

[joe_l]

2 minutes ago, markw said:

But should that step really be necessary?

I would say No, so this thread could be worth a bug report in the Mac section.

[loukash]

1 hour ago, Thomahawk said:

What else can be done?

Use vector QR codes instead!
Virtually every online QR code generator will make you one.
All. Problems. Gone.

[loukash]

Naja, ganz genau genommen ist es offenbar ein "RetourenDatamatrixCode (DmC)"…
Kannst du den nicht als Vektoren bei der Post exportieren?

[lacerto]

Please find attached a fixed version of your Designer file.

The three images that you had in the job were CMYK files with four-color blacks. They might initially have been 1-bit monochromes, which Affinity apps do not support, and if opened or placed in Affinity apps, will be interpreted as RGB images. When converted to CMYK, they will become four-color blacks (according to conversion based on underlying profiles). In a CMYK document placed RGB and CMYK images can be forced to be handled as grayscale images (K-Only button on the toolbar, when image objects are selected). When doing so, pure RGB 0, 0, 0 images will become Grayscale 100% (or G0 or B0, as they are labelled in Affinity apps). True grayscale images will have the K-Only button turned on when these kinds of images are placed in a CMYK document, which forces them to be processed as grayscale images at export (internally these files are handled as RGB files).

I converted these three images to grayscale images. I left the QR code as 22 x 22px. It stays that way, when exported, but will just be resampled when processed, duplicating pixel values without antialiasing. If you open a PDF with this kind of an image, it will be antialiased when opened in Affinity Photo (but if you open and interpret a file that needs to be rasterized/rendered in e.g. Photoshop, you can choose to turn off antialiasing). If you view the PDF in something like Adobe Acrobat Pro, you should see the image sharp and non-antialiased.

The file exports exactly similarly on Windows and macOS. In the attached PDF (exported on Windows), all black values are now either DeviceGray values or DeviceCMYK values with mere K values.

Why the problem appeared to become "fixed" by rasterizing is that when you rasterize an image layer on canvas, the rasterization will be done at the document resolution (which was set to 1200dpi in this document), and accordingly the low-res 22 x 22px image will be upsampled (using bilinear algorithm, which is not optimal when upsampling this kind of image, as it should be done using the nearest neighbor algorithm). This, indeed, is not necessary, so you can leave upsampling to RIP.

(Why the QR Code appears so pixelated in your screenshot is probably caused by viewing an antialiased 22 x 22px image at close range (antialiasing done by the viewer app); had you printed the original exported image, you would have had nearest neighbor upsampled four-color blacks which would probably have worked without problems, but less than ideally as these kinds of images should typically use black ink only.)

sample_fixed.afdesign

sample_fixed.pdf

 

[loukash]

On 12/19/2022 at 1:22 PM, Thomahawk said:

What else can be done?

On 12/19/2022 at 3:19 PM, loukash said:

Use vector QR codes instead!
Virtually every online QR code generator will make you one.
All. Problems. Gone.

So…
The quick and easy fix for good:

1. zoom in your placed QR code so that it's large enough on your display, the larger the better
2. take a screenshot of it (on Mac: cmd-shift-4 and drag the area)
3. upload the screenshot e.g. to vectorization.org
4. download the SVG and open it with Designer
5. merge all curves into one Curves object (having just one object is easier to handle)
6. copy the QR to your layout
7. apply K100 (because it will be rich black by default)
8. voilà, takes about a minute of work

dmc_converted.svg

[loukash]

2 hours ago, BofG said:

calling this a QR code

Fair enough, the Scandit app reads it under "2D code".

[lacerto]

On 12/19/2022 at 6:33 PM, BofG said:

Technically that isn't a QR code, it's a "2D" barcode.

Thanks for pointing this out. I did not know about different kinds of 2D codes (and I suppose the only kinds I have ever generated have been QR codes).

The inventor of QR has this info page (do not know how objective information it provides):

https://www.denso-wave.com/en/adcd/fundamental/2dcode/2dcode/

As for offline tools, at least Inkscape can produce Datamatrix codes (which I suppose the specific 2D code of this post was)...