Re: Colorsync-users Digest, Vol 6, Issue 112
Re: Colorsync-users Digest, Vol 6, Issue 112
- Subject: Re: Colorsync-users Digest, Vol 6, Issue 112
- From: Jon Kovach <email@hidden>
- Date: Wed, 10 Jun 2009 08:38:28 -0400
- Thread-topic: Colorsync-users Digest, Vol 6, Issue 112
Is the banding going back and forth from blue to purple, in a consistent
pattern, all the way through the color? If so, I don't think that is a
screening issue, though I could be wrong. What other kind of dot pattern
would fix it, if stochastic makes it happen?
Any chance the banding would show up in a photograph?
I have lots of experience with banding, and I have never seen unidirectional
printing fix banding.
Jon
>
> Interesting, I kept telling them I thought it was a screening issue.
> Deaf ears, that what I got for my troubles.
>
> Onyx wanted me to erase the printer hard disk to remove "varware". HP
> says that would take either six hours or 40 hours depending on the
> format level. However, I have yet to hear about the effectiveness of
> erasing the disk which would also mean removing a working printer
> from production for a day. Firmware was suppose to fix it, RIP
> updates were suppose to fix it... HP support was supposed to talk to
> Oynx support...
>
> I see the problem on two different printers when using Onyx, from two
> different installs of Onyx. Both printers work fine with any media
> when using the HP RIP. I ran media adjust on the Printer and measured
> the distance scale printed from Onyx which was short by 3/64 of an
> inch for the 36 inch test. That also had no positive result for
> removing the banding that Onyx produces.
>
> The banding is broad, about a 1/4 wide and in the case of the solid
> navy color it goes from correct color to bands that don't have enough
> cyan so they show up as magenta bands, also about 1/4 inch wide. This
> is bidirectional printing, which again works fine from HP. I have not
> tested unidirectional because we don't want to run at half speed with
> Onyx, that just doesn't seem like a solution, double the time it
> takes to print.
>
> Graeme, private message me your contact info and I will pass it along.
> And thanks, I will play with GCR more and see if I have any success.
>
> Also, I will be away from this post for the next week as I'm out of
> the office.
>
> Thanks everyone.
> David
>
>
> On May 22, 2009, at 1:04 PM, email@hidden
> wrote:
>
>>
>> david wollmann wrote:
>>
>>> Where it always fails for me, with any media, is when I try to
>>> print a
>>> solid color such as Pantone 2767, a dark navy, I get banding. This
>>> happens with other similar dark navies, some dark purples and also
>>> with
>>> some black builds. All media settings match up on RIP and printer.
>>> Different pass modes simply alter the distance between the banding.
>>
>>> What am I missing? Anyone else having problems?
>>
>> The RIP can contribute to banding in two ways:
>>
>> Black generation:
>> If GCR is high, then dark colors will be dominated by the
>> black
>> channel and any banding present in it. A GCR level in which
>> all
>> the channels are roughly even minimizes banding.
>>
>> Multi-level screening algorithm.
>> An unsophisticated multi-level screening algorithm will
>> show up banding as the screen starts to get full with one
>> dot size (or light ink) before starting to add the next
>> biggest
>> dot size (or darker ink).
>> A banding aware screening algorithm will avoid this
>> situation.
>>
>> My guess is that the second problem is the one you're seeing.
>> Perhaps you should tell them to contact me - I have a banding aware,
>> multi-level screening algorithm I could license to them :-)
>>
>> cheers,
>>
>> Graeme Gill.
>>
>
>
>
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> End of Colorsync-users Digest, Vol 6, Issue 112
> ***********************************************
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>
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