R plots pdf() does not allow spotcolors?
Barry, thanks a lot for checking for this!! Find below answers. Le 13. 04. 11 18:26, Barry Rowlingson a ?crit :
2011/4/13 Matthieu Stigler<matthieu.stigler at gmail.com>:
Jim Thanks for your feedback! The problem is that the people "those responsible for layout" are us... We are doing the book in Latex, and till now did not need any other software. But I am scared we will need use kind of Indesign& co softwares to be able to use our R plots, since R can't export into spotcolor...
I've just had a look into how PostScript handles spot colours, having been hacking PS files for many years its not something I'd played with before. This page gave me a PS file that used spot colours: http://pslib.sourceforge.net/examples.php and it seems that you can set a colour using a colour space array: [ /Separation (PANTONE Violet C) /DeviceCMYK { dup 0.750000 mul exch dup 0.940000 mul exch dup 0.000000 mul exch 0.000000 mul } ] setcolorspace 1.00 setcolor Now, my screen previewer has no idea what colour PANTONE Violet C is, so there's an alternative CMYK colour space version. In fact PANTONE Violet C is just a label. The idea is that when processed for colour separations the software will use the separation colours. Now, to get this into R is tricky. Either you have to rewrite the PS driver or hack the PS output file. I produced a simple R plot with one purple (col="#FF00FF") blob and saved to a PS file. The bit of the PS that set the colour was this: /bg { 1 0 1 rgb } def 1 0 1 rgb
I do no get something similar... I used:
set.seed(123)
a<-runif(100)
postscript("RplotRGB.ps", colormodel="rgb")
plot(a, col="#FF00FF")
dev.off()
Interestingly, I compared with:
postscript("RplotCMYK.ps", colormodel="cmyk")
plot(a, col="#FF00FF")
dev.off()
and making a diff, I see only:
87c87,88
< 1 0 1 rgb
---
> 0 1 0 0 setcmykcolor
>
194c195,196
< 0 setgray
---
> 0 0 0 1 setcmykcolor
>
278c280,281
< 0 setgray
---
> 0 0 0 1 setcmykcolor
>
does not look so similar to what you obtained...
- the two settings here are for the outline and fill of the blob, which was created using pch=19.
may I ask you what are outline and fill?
To specify this as a spot colour (with a CMYK alternative for
preview), I changed that to this:
/pvc {
[ /Separation (PANTONE Violet C)
/DeviceCMYK { dup 0.750000 mul exch dup 0.940000 mul exch dup
0.000000 mul exch 0.000000 mul }
] setcolorspace
} def
/bg {
pvc 1.00 setcolor
} def
pvc 1.00 setcolor
Now if you only have one or two spot colours and only a few places
where they occur then it might be possible for you to do this kind of
edit/replacement - either manually or automatically. And beware I'm
not even sure this is right or that your publisher would be happy
anyway.
no but seems quite a nice solution, as I have only known cmyk colors (5) for which I can find Pentone matching. Could setup small script then! Just need to figure out why we do not get similar results you and me!! Thanks so much!!
Anyway, thats enough PS hacking for one day. Barry