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Moiré?

2015-12-01 by stefanchristiansen@...

I might have a weird question.

Assuming printers are not supposed to print the same amount of C and LC or M and LM at the same time (except perhaps at one crosspoint), is it possible that X and LX channels have the same dithering?

Then could there be some moiré if those channels are used with the same gray ink dilution and the very same curves and ink limits?

I'm having some artefacts at a lager scale than what usually happens with nozzle or head alignment issues.

Those wouldn't be visible in a positive print on paper but show when printing negatives on transparencies.

Epson 1500W (=1430), Print-Tool, El Capitan.

Thanks for your help.

Stefan Christiansen

Re: Moiré?

2015-12-02 by stefanchristiansen@...

In response to a private answer:

Thanks for the suggestion.

I wish it was newton rings, I could solve it.

But those artefacts have a chevron-patterned aspect and can be observed on a light table.

I tested different channels combinations (same ink dilution in each), and it really looks like cutting down LC and LM (and rising other channels) makes great improvements, campaigning for a sort of conflict between X and LX channels if used equally.

This might not sound that much related to QTR, but I remember a discussion where it was stated that QTR uses its own dithering algorithms and that every channel has its own dithering placement of drops, contradicting a moiré possibility.

I hoped to get a deeper understanding of eventual dithering patterns interactions.

Moving on anyway…

Stefan Christiansen

Re: [QuadtoneRIP] Re: Moiré?

2015-12-02 by Roy Harrington

Stefan,

Can't give you any real answer. But yes the dithering is different on each channel.

They are all designed to avoid patterns and moire.

Roy

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On Wed, Dec 2, 2015 at 6:14 AM, stefanchristiansen@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

In response to a private answer:

Thanks for the suggestion.
I wish it was newton rings, I could solve it.
But those artefacts have a chevron-patterned aspect and can be observed on a light table.

I tested different channels combinations (same ink dilution in each), and it really looks like cutting down LC and LM (and rising other channels) makes great improvements, campaigning for a sort of conflict between X and LX channels if used equally.
This might not sound that much related to QTR, but I remember a discussion where it was stated that QTR uses its own dithering algorithms and that every channel has its own dithering placement of drops, contradicting a moiré possibility.
I hoped to get a deeper understanding of eventual dithering patterns interactions.

Moving on anyway…

Stefan Christiansen

Roy Harrington
roy@...
www.harrington.com

Re: [QuadtoneRIP] Re: Moiré?

2015-12-02 by Stefan Christiansen

Very good to know.
Still, things look like there is some kind of resonance. But that's just a feeling.
Thanks for this information.


Stefan

QTR-Quadtone RIP

Moiré?

Moiré?

Re: Moiré?

Re: [QuadtoneRIP] Re: Moiré?

Re: [QuadtoneRIP] Re: Moiré?

Move to quarantaine