Printers are allway dependent on setup of colour management in its driver. Pro printers are dependent on setup of RIPs sending data to them. Not easy task. Martin S. Odesláno z iPhonu 11. 8. 2021 v 21:15, Bruce Mutton <bruce@tomo.co.nz>:
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 <therion-bounces@speleo.sk> On Behalf Of Martin Budaj Sent: Wednesday, 11 August 2021 07:23 To: List for Therion users <therion@speleo.sk> 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 <bruce@tomo.co.nz> 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). <image002.jpg>
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. <image004.png>
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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