Re: solid K or open K
Re: solid K or open K
- Subject: Re: solid K or open K
- From: David Wollmann <email@hidden>
- Date: Fri, 01 Nov 2002 11:50:38 -0700
- Organization: Luna Vista Imaging
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At 12:03 AM -0700 10/29/02, David Wollmann wrote:
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>I was wondering what sort of problems might arise from using a black
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>that is restricted so much that 100% produces an open solid black patch?
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>In other words dots can be seen in my 100% K patch without using a
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>loupe.
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This comes down to how you do your ink limiting. Cheaper RIPs only allow you to limit ink per channel. That means that if you want 150% coverage you need to reduce the max of each channel so when they add together they never get above 150%. I have always disagreed with doing things this way.
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Postershop, on the other hand allows you to set ink limits per channel as well as a total ink limit. Despite this ability I have seen Onyx documents say to do all sorts of per channel limiting. If you carefully set the limits so that you get good density per channel and then concentrate on the total ink limit to control ink puddling then you will get much better results. I have seen systems set where we had up to 100% per channel but a total ink limit of 125%. A low ink limit to be sure but rich saturated colors and decent shadows and blacks too.
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Wow, that certainly is a low Ink Limit. I think that in some of the early documents that Onyx supplied they recommended not going under somewhere around 200%, but I suppose this would really depend on where the individual channels are starting from. In your example they begin at 100% of output for that head, if they were already restricted to say 50% I can see where that might cause additional problems.
I have never wanted to do to much with the Ink Limit step for fear of messing things up, most likely from reading some of the propaganda from Onyx, preferring instead to dial the heads in on my own and then try to run close to 400%. Now with some of the problems I am having with one of my printers and experimenting with reducing the black I am inclined to rethink things and learn additional approaches.
I do of course like the idea of keeping everything where it can produce a solid patch, and use the Ink Limit to rein things in from there. In PosterShop 5.6.1 there is a setting in the Tweak Dialog for the Ink Limit that I was wondering if you can shed some light on. I have read conflicting statements from Onyx on the use of this check box that says "Allow Modification of GCR to meet Ink Limit".
Currently I am allowing it to be on from 4.0 to 3.5 and under that I turn it off, I believe this info came from a tech support guy.
Do you know when this should be invoked, when it should not, or even if it should be invoked? Even with the pre-built profiles supplied by Onyx for use with the ColorSpan printers, I can not take many clues from their use of it because they are not consistent in their own approach.
Onyx PosterShop has a tremendous amount of control and many different ways to do things. I just wish they published more white papers on how to take advantage of everything, plus if they eliminate the conflicting statements that helps the most.
Thanks,
David Wollmann.
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