[Scribus] Black becomes lighter when exported to PDF

[John Brown]

Craig Ringer <craig at ...> writes:

> 
> Marcin Szafran wrote:
> 
> >>
> >> How can I fix this?
> > check your colour profiles - ... also check if 
> > your black is cmyk black (c0 m0 y0 k100) and not rgb.
> 
> Using the relative colorimetric rendering intent with black-point
> compensation, RGB (255,255,255) should end up as a CMYK black...
>
> Craig Ringer
> 

It turns out that if I choose Output Intended for Screen/Web in PDF
Export, then the PDF looks like the Scribus document. When I choose
"Printer", all the colours (not just black) become slightly washed out,
as if I had reduced the opacity. It prints that way on my
black-and-white laser printer as well. 

1) Does it really matter whether I choose "Screen" or "Printer"? 

2) Does it really matter whether I use RGB or CMYK? I am using a few
basic colours: 
Red RGB(255,0,0) or CMYK (0,100,100,0) 
Black RGB(0,0,0) or CMYK(0,0,0,100) 
plus colours in an imported SVG file. 

That is, I have two test documents: one that uses only RGB and one that
uses only CMYK. 

Scribus says that I am also using "White", but I cannot see where. After
I removed unused colours, "White" remained, but I have not coloured
anything white as far as I can tell. 

The PDF looks the same whichever format is used. 

Would it be OK to send one of my test .sla files? If yes, which one
should I send? 

I don't know anything about colour profiles and things like that. I am
just manipulating objects on the screen until I like what I see, so I
could be making a very simple mistake somewhere. 

I recently upgraded from Ghostscript 8.57 (which I was using when I
started designing the sign) to 8.60, but it did not help.