Re: GCR Problem
Re: GCR Problem
- Subject: Re: GCR Problem
- From: Jon Crook <email@hidden>
- Date: Mon, 02 Feb 2009 12:42:14 -0600
- Thread-topic: GCR Problem
Ok, I lowered my K-start to 10% and that did not make a difference on the
build we are discussing; however it did lessen the amount of black that is
taken out of the other photographs in this project.
This seems to be over-engineered for what Im trying to do with it. I am not
using this particular workflow for profile conversions, Im just using it for
GCR conversions. Is there a better way to do this?
Seems to me that if some kind of software would just go through an image
pixel by pixel and apply GCR to a certain E off of neutral then this would
accomplish what I am after.........I think.
I know what I am after but Im not sure of the best way to get there.
On 2/2/09 11:29 AM, "Steve Miller" <email@hidden> wrote:
>
> 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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--
Jonathan Crook
Director of Color Management
Corporate Image
www.corp-image.com
800.247.8194
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