Re: GCR Problem
Re: GCR Problem
- Subject: Re: GCR Problem
- From: Jon Crook <email@hidden>
- Date: Mon, 02 Feb 2009 13:24:56 -0600
- Thread-topic: GCR Problem
That is correct but with a tolerance that will allow a certain amount of
colorimetric accuracy.
I made a box of the build in question in InDesign and it went through
unchanged. Its seems it is just the CTs that are changing. Based on this I
think that the scum dot theory may be correct. If this is correct then it
makes this product useless for this particular function.
Does anyone have any ideas? What are all of you using?
On 2/2/09 12:54 PM, "Terence Wyse" <email@hidden> wrote:
> You're looking for logic that says...
>
> If current K is >= GCR logic results: leave K unchanged.
> If current K is < GCR logic results: convert.
>
> Not sure how to do that with CMYK Optimizer or other products but it
> does seem "simple" though.
>
> Terry
>
>
>
> On Feb 2, 2009, at 1:42 PM, Jon Crook wrote:
>
>> 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
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Do not post admin requests to the list. They will be ignored.
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>>>>>
>>>>> This email sent to email@hidden
>>
>> --
>> 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
>
>
>
> _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> Colorsync-users mailing list (email@hidden)
> Help/Unsubscribe/Update your Subscription:
>
> This email sent to email@hidden
--
Jonathan Crook
Director of Color Management
Corporate Image
www.corp-image.com
800.247.8194
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