Thanks Martin

Highlights the dangers of absorbing a language by osmosis.  A false sense of 
understanding!

I’ll try that out and see how it works.

 

Out of interest I went back over old maps to check the colour of my gridlines.  
Until a few weeks ago I only ever used the default rgb colour model, and even 
now I only specify rgb, but occasionally force Therion to convert by specifying 
a cmyk colour model.  I found that I actually got a random section of the two 
gridline output colours over previous years.  My excuse for not picking it as a 
Therion behaviour is that I routinely use a number of pdf viewers and printers. 
 They all present line thicknesses and colours slightly differently. Especially 
Sumatra pdf compared to most others.

 

Bruce

 

 

From: Therion <[email protected]> On Behalf Of Martin Budaj
Sent: Wednesday, 11 August 2021 07:23
To: List for Therion users <[email protected]>
Subject: Re: [Therion] Plan gridline colour changes unpredictably

 

Hi,

 

0.5white doesn't work in CMYK properly (it's equivalent to 0.5*(0,0,0,0) = 
(0,0,0,0) = white)

0.1black doesn't work in RGB (it's 0.1*(0,0,0) = (0,0,0) = black)

 

So your formula produces 50% gray in RGB and 10% gray in CMYK. No idea why you 
got 10% gray in some RGB setups, some test data would be needed.

 

To get 10% grey colour you need to use 0.1[white,black] which works in all RGB, 
CMYK and Grayscale.

 

Cheers

Martin 

 

 

On Tue, Aug 10, 2021 at 11:29 AM Bruce Mutton <[email protected] 
<mailto:[email protected]> > wrote:

Curious

 

I have in my layout some metapost code to redefine the plan gridlines, used 
without apparent problem for perhaps 10 years.  It includes a colour 
specification…

 

withcolor 0.1black+0.5white;

 

Mostly they come out like this, very light grey.  This example is exported 
using colour-model cmyk, but most of the time using colour-model rgb it looks 
exactly the same, in my current project (only variables are colour map-fg, some 
map previews on or off and the colour model).



 

For some reason, in my current project, if I use colour-model rgb for a 
particular output variant, I get a much darker gridline, as below.  Other 
variants with rgb, the colour of the gridline matches the first example.



 

Any hints as to why the difference?

I might have expected this to occur with the new cmyk colour model, but it does 
not.

So far it has only happened with in a single specific case when using the rgb 
colour model.  I’ll watch for more cases…

Bruce

 

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