Re: Light Generation-clarification on how to prepare
Re: Light Generation-clarification on how to prepare
- Subject: Re: Light Generation-clarification on how to prepare
- From: Steve Upton <email@hidden>
- Date: Thu, 22 Jul 2004 11:06:45 -0700
At 9:50 AM -0700 7/22/04, Doug Walker wrote:
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I am wondering what the real skinny is on Light Generation.
I was a little confused on this one until I realized you are talking about Black generation.
This is an important distinction as we are not talking simply about lightness vs blackness but about actual black ink.
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My printer at a bucket shop/Web press wants me to use Light Generation which helps them adjust on the press on my next CMYK delivery.
a typical desire, not necessarily recommended though. More info below...
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I have been reading here that the Medium or Heavy will keep the image more pure. US Web Coated SWOP v2 is Medium as a default already right? So I am at the proverbial crossroads once again. We are essentially printing a bunch of neutral grey and black metal product images in this application at this printer.
Black generation is basically about replacing color ink combinations that are neutral (or have neutral components) with black ink. This is a powerful technique for a number of reasons.
For neutral and near neutral colors, the more you use black ink, the less chance that any drift on press in the C, M or Y channels will affect the color. If you have neutrals that you are concerned about, AND you are confident that you don't have color casts in them, then you should create CMYK with a higher black generation.
This tendency to avoid shifting on press makes some printers nervous. If you give them a file that is not well corrected and you want the printer to be able to correct some cast on press you are going to be out of luck.
It's fair to say that color correction should NOT happen on press and if you are creating bad images then you need to look somewhere other than the press for corrections!
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If I understand correctly, And in keeping with this, I have also been told that if you invoke Custom CMYK dialog box found in Photoshop>Color Settings to alter things such as TAC, or select Light Generation, it is a low grade solution as it builds a profile that is comprised of very few points, is small, and not very accurate. Yes? No?
yes, probably. The newer, more robust profiles will probably give you better results. The problem is they have fixed black generation.
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I still see this touted in todays digital magazines as a proper method of tailoring CMYK output. Just got one in the past couple months.
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Are they disseminating old marginal information?
they might be. It is still the only way to customize black generation within Photoshop.
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Wouldn't one be best served by simply doing a better job of adjusting or preparing an image in RGB, with Soft Proof side by side with regards to forcing the proper end points and pulling off some heaviness via curve adjustments so that the numbers needed for TAC, etc.. are in place before AND THEN CONVERT to the destined US Web SWOP Coated v2 profile.
yes, yes, yes
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I am nervous about mucking with the old Legacy PS4 CMYK SWOP Engine just to force a Light Generation.
be nervous about light generation as well.
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Is the Chromix's Light Generation 280 profile I keep hearing everyone talk about simply a US Web SWOP Coated v2 profile with a Light Generation and 280TAC as opposed to standard Medium and 300?
sort of. I built the profiles from the same TR001 data that the US Web Coated is based on. I then build a set of them with differing ink limits (the 300 is the one that's truly SWOP compliant) and differing black generation.
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If so, it would seem then that a solution like that would be much safer than invoking the ol Legacy PS4 engine.
I think it is safer but less flexible.
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o email@hidden 206.985.6837
o ColorGear ColorThink ColorValet ColorSmarts ProfileCentral
________________________________________________________________________
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