Re: GCR Problem
Re: GCR Problem
- Subject: Re: GCR Problem
- From: Steve Miller <email@hidden>
- Date: Mon, 02 Feb 2009 11:29:18 -0600
- Thread-topic: GCR Problem
Jon,
Your original separations have 11% K in them. You moved your K-start to 15%.
This could be the reason you are still not getting the amount of black you
want.
Move you K-start to 10% and let us know what happens.
Regards,
Steve
On 2/2/09 11:24 AM, "Jon Crook" <email@hidden> wrote:
> 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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--
Steve Miller
Norwood Publishing
1000 Highway 4 South
Sleepy Eye, MN 56085
507-794-8203
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