Re: [NTG-context] color question
> Am 24.08.2020 um 01:15 schrieb jbf : > > I have a very basic question about color use that someone will be able to > answer easily. The background to the question is that (i) I am completely new > to this scene of commercially[offset] print-ready material as distinct from > what is required on screen (ii) I am using Mk IV (iii) I need spot colors set > up for cmyk, and for now I need shades between black and white (e.g. light > gray) for a simple design feature. > > My question is this: is the use of color keywords sufficient? Or in other > words, have predefined color names like lighgray already been defined in, say > cmyk terms behind the scenes, or must I instead > \definecolor[lightgray][c=10,m=7,y=5,k=0], (or perhaps \definespotcolor > with those dimensions, or do I need both)? First: Color parts use decimal numbers from 0 to 1. Even if some color names are predefined, you should define your grays yourself – either as shades of black only or maybe with a bit of cyan. Grays in more (process) colors are unstable and might get a tint (color cast) you don’t want. (Of course you could use other colors than cyan for some tinting, depending on your work.) E.g. I often \definecolor[deepblack][c=.3,k=1] for black areas; the cyan portion evens out some irregularities in print. Because I don’t trust ConTeXt’s (or my) color setup, I also \definecolor[cmykblack][k=1] to avoid “RGB black”. (But \setupcolor[cmyk=yes,rgb=no,overprint=yes] should handle that already.) If you want to use grays as spot colors (e.g. Pantone) you must define them as such – but usually you don’t want (to pay for) more than one spot color. Spot gray makes sense if you have big areas of that color, since 100% spot color looks better than any percent rastered black. See also: https://wiki.contextgarden.net/Color https://wiki.contextgarden.net/Spot_Colors Hraban (printing engineer) ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___
[NTG-context] color question
I have a very basic question about color use that someone will be able to answer easily. The background to the question is that (i) I am completely new to this scene of commercially[offset] print-ready material as distinct from what is required on screen (ii) I am using Mk IV (iii) I need spot colors set up for cmyk, and for now I need shades between black and white (e.g. light gray) for a simple design feature. My question is this: is the use of color keywords sufficient? Or in other words, have predefined color names like lighgray already been defined in, say cmyk terms behind the scenes, or must I instead \definecolor[lightgray][c=10,m=7,y=5,k=0], (or perhaps \definespotcolor with those dimensions, or do I need both)? Julian ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___
Re: [NTG-context] color question
On Oct 10, 2006, at 12:30 PM, [EMAIL PROTECTED] wrote: On 10/10/06, Alan Bowen [EMAIL PROTECTED] wrote: If this is OT, my apologies to all. I am currently using ConTEXt to produce PDFs with a colored background which I specify using R G B settings. Unfortunately, this background does not look the same when others open the files on their computers. Is there anything I can do at my end to correct this? There are well-known differences between various computer brands, and individual PC's generally vary widely. If you need really good agreement, then all the systems need to be viewed under similar light conditions and calibrated (e.g., using a colorimeter, or at least the GretagMacbeth ColorChecker, a printed chart) and you want to generate PDF's with a specific colorspace (not just deviceRGB). For most purposes, it seems to work to use a rough sRGB setting where you adjust the monitor (brightness, contrast) to approximate gamma=2.2. Check this with: http://www.normankoren.com/ makingfineprints1A.html#Monitor_test_pattern. Many LCD's and worn-out CRT's like the ancient NCD on my desk will fail even this simple test. -- George N. White III [EMAIL PROTECTED] Head of St. Margarets Bay, Nova Scotia Henning and George— Thanks for the replies. I had suspected that I was at the start of a search for yet another Holy Grail. Still, I will look into this sRGB (which is new to me), but first I had better see if I can calibrate my own monitor properly. (It failed the Monitor test.) Alan ___ ntg-context mailing list ntg-context@ntg.nl http://www.ntg.nl/mailman/listinfo/ntg-context
[NTG-context] color question
If this is OT, my apologies to all. I am currently using ConTEXt to produce PDFs with a colored background which I specify using R G B settings. Unfortunately, this background does not look the same when others open the files on their computers. Is there anything I can do at my end to correct this? Alan ___ ntg-context mailing list ntg-context@ntg.nl http://www.ntg.nl/mailman/listinfo/ntg-context
Re: [NTG-context] color question
On 10/10/06, Alan Bowen [EMAIL PROTECTED] wrote: If this is OT, my apologies to all. I am currently using ConTEXt to produce PDFs with a colored background which I specify using R G B settings. Unfortunately, this background does not look the same when others open the files on their computers. Is there anything I can do at my end to correct this? There are well-known differences between various computer brands, and individual PC's generally vary widely. If you need really good agreement, then all the systems need to be viewed under similar light conditions and calibrated (e.g., using a colorimeter, or at least the GretagMacbeth ColorChecker, a printed chart) and you want to generate PDF's with a specific colorspace (not just deviceRGB). For most purposes, it seems to work to use a rough sRGB setting where you adjust the monitor (brightness, contrast) to approximate gamma=2.2. Check this with: http://www.normankoren.com/makingfineprints1A.html#Monitor_test_pattern. Many LCD's and worn-out CRT's like the ancient NCD on my desk will fail even this simple test. -- George N. White III [EMAIL PROTECTED] Head of St. Margarets Bay, Nova Scotia ___ ntg-context mailing list ntg-context@ntg.nl http://www.ntg.nl/mailman/listinfo/ntg-context
Re: [NTG-context] color question
Am 2006-10-10 um 13:52 schrieb Alan Bowen: I am currently using ConTEXt to produce PDFs with a colored background which I specify using R G B settings. Unfortunately, this background does not look the same when others open the files on their computers. Is there anything I can do at my end to correct this? Color almost never looks the same on some other screen - you can't force everyone to calibrate theirs and use proper color management settings... Greetlings from Lake Constance! Hraban --- http://www.fiee.net/texnique/ http://contextgarden.net http://www.cacert.org (I'm an assurer) ___ ntg-context mailing list ntg-context@ntg.nl http://www.ntg.nl/mailman/listinfo/ntg-context
