Bitmap PNG in publisher

[krikor]

Hi

I'm switching from Indesign to publisher and I have a question regarding handling of Bitmap PNG files.

I'm used to assign a print color in the application itself or a no color/paper and a background color, but it seems publisher doesn't handle it the same way.

When I opened IDML files with such layers they appear as black bitmap files.

what would be the right way to do this?

Best

 

[loukash]

[krikor]

Thanks, I saw your answer on my other post only after I made this one.

I still have things I don't understand regarding layers and inversion of BM. 

I have a bitmap and I want black to be a color and white to be no print, or reverse. an I want the image in the background to be visible thru it.  In my example attached I would like the image on the right to act as the one on the left (which came from an IDML file originally)

TEST.afpub

[loukash]

You must delete the white background to make it transparent.

1. make the placed original negative PNG linked to make it editable
2. click the Edit Image button > opens in new tab > switch to Photo persona
3. Layer > Invert
4. flood-select the background, non-contiguous
5. delete (and clip canvas if you wish, you don't necessarily need the blank space around it)
6. export as grayscale 2-color palettized PNG to retain both the 1-bit attribute and the alpha channel
   
7. replace existing placed image or place again, embed or keep linked ias you see fit
8. Do! Not! Rasterize! that placed "Image"-type layer!

[krikor]

thanks a lot!

Is there a way to make all image "linked" by default and not imported?

[loukash]

Document Setup > Image Placement Policy

[loukash]

P.S.
Be aware that black overprint in Affinity is, to put it very mildly, wonky.
In your document, the K plate will knock out the CMY background behind the placed image on PDF/X1 or X3 export, no matter what I've tried so far.

If you want to have some fun – or rather bang your head against a wall – enjoy reading this thread on a related topic:

The overprint attribute only works with spot colors on placed images.

You must also disable the Downsample Images setting on PDF export if your 1-bits are 600 dpi or higher.

There are quite a few issues here. I would avoid 1-bit images whenever possible and vectorize them with a 3rd party app instead.

[loukash]

Alright, upon some further testing:
If you don't use any spot colors below, you can set the placed image layer blend mode to Darken. This will behave like overprint, be it black or any CMYK tints. Works – logically – even for placed images without alpha channel: the image white "darkens" as "transparent". Make sure to place any K100% text or vector objects on top though, otherwise the Darken blend mode can break its K100 "auto-overprint" functionality.

In any case, since Affinity apps sadly lack any overprint preview, make sure to double-check any PDFs with Acrobat Pro or equivalent before sending to print.