Re: GCR Problem
Re: GCR Problem
- Subject: Re: GCR Problem
- From: Jon Crook <email@hidden>
- Date: Mon, 02 Feb 2009 11:24:45 -0600
- Thread-topic: GCR Problem
I threw colorimetric accuracy out the window and lowered my K-start to 15%
and switched on CK-MK-YK ink purities and it was still pulling from the K
sep and adding to the CMY sep. It wasn't as bad but still present. There has
got to be a way to do these separations reliably.
On 2/2/09 10:51 AM, "Terence Wyse" <email@hidden> wrote:
> Hi Jon,
>
> If you're using CMYK Optimizer and the "dynamic" GCR option, the
> resulting conversion can be somewhat unpredictable. It's based on a
> lot of factors including the actual pixel area in the image. While not
> exactly your issue, the program will tolerate a certain amount of
> excessive total ink coverage depending on the actual pixel area that
> it's sampling and how large it is.
>
> In your case, it might be as simple as the where you have the K start
> point set in the GCR setting. If your K start point is, say, 25%, then
> what you're seeing would be expected where it would actually REMOVE K
> and convert back to CMY. Only solution would be to start the K as
> early as you can tolerate.
>
> There's another way to prevent this from happening that may be the
> best option. In CMYK Optimizer you should have control over the primary
> +K combinations (CK, MK and YK). By checking this option on, it should
> prevent what you saw happen. You can do the same for secondary+K
> combinations as well (CMK, CYK, MYK).
>
> Regards,
> Terry Wyse
>
>
>
> On Feb 2, 2009, at 11:25 AM, Jon Crook wrote:
>
>> I need help understanding what is going on behind the scenes in
>> Alwan CMYK
>> Optimizer. I have it set to apply a certain level of GCR and works
>> beautifully most of the time but once in a shile I get an image that
>> seems
>> to separate the exact opposite to the way that I intend.
>> Here is an example:
>> Original build is C=0 M=0 Y=27 K=11
>> New build through Alwan C=11 M=4 Y=36 K=0
>> Correct me if Im wrong but isnt this conversion the exact opposite
>> of what
>> GCR should be? Since there was not any Cyan or Magenta in the original
>> build, I would think that there would be no conversion at all. Im
>> sure Alwan
>> applies GCR the same way as other ink optimizing programs. Can
>> anyone tell
>> me exactly what is going on behind the scenes so I can better
>> understand
>> this process.
>>
>> Thanks,
>>
>> --
>> Jonathan Crook
>> Director of Color Management
>> Corporate Image
>> www.corp-image.com
>> 800.247.8194
>>
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>
> ______________________________
> Terence Wyse, WyseConsul
> Color Management Consulting
> G7 Certified Expert
>
>
>
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--
Jonathan Crook
Director of Color Management
Corporate Image
www.corp-image.com
800.247.8194
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