Hi ! I'm new to Scribus (and text publishing in general ^^) and there is something I don't understand. I hope someone can help me. Sorry for my english, I'll try to explain the best I can.
I'm making a little newspaper. I placed some elements for my layout (images, text blocks, etc...), and I wanted to test for printing, but there is always a problem somewhere.
If I try to print directly from Scribus, the transparent(alpha) of my PNGs images appears in big white.
Exemple:

If I export in PDF before printing, the transparent(alpha) of my PNGs images are ok, but the text color in my text blocks print all black (I have some white text over images to tell the source or to comment.)

I tried many different settings from what i read here and there but it is impossible for me to do what I want and it is very frustrating.
From what I understood, this can be a problem with color management, font import/embbed, or maybe a setting that I forgot/overlooked.
I tried to activate color management.
I tried to use the two different whites (RGB and YCMK):

I tried to embbed the font. I tried to vectorize the font.
I tried to export pdf with different settings (1.4, 1.5, with or without compression, etc...)
No matter what, even when looking at the PDF where the font seems white, Arial stays black when I print.
The only solution that works I have found so far is to export my .sla in png images. There, the font colors and png transparency are both ok and I can print and get what I want.
Another thing that works, is if I use an OpenType font, the text will print in white. But all TrueType fonts print in black.
What I want when I print my exported PDF:

If someone can give me a clue about all this, I'll be very thankful.
(I attach the .sla file in the post in case you want to look at it)