Single Strike/Double Strike ink restricions?

[M.A.C.]

Onyx now offers the option of setting your double strikes for your light inks as well for certain profiles, So the options for a D.S. profile for Cyan would look like :

lc1:
lc2:
C1:
C2:

Would we treat our lc1 and lc2 the same as C1 and C2 (Begin removing from C2 until 0 is reached, then begin removing C1)?

Examples.

100% Cyan desired:

lc1:100
lc2:80
C1:100
C2:100

40% Cyan desired:

lc1:72
lc2:0
C1:80
C2:0

??

Thanks

[eye4clr]

are those double strikes or different dot sizes?

For most piezo heads they are dot size differences. For most thermal heads, they are double strikes.

[M.A.C.]

*I would assume double strike as we are using thermal printing.










*I am often/usually wrong

[torpedo]

I'm pretty late on this but I think I can throw in something.

> C1, C2, etc. issue:

This's actually called "double-layering technology" by HP. It's just that the ink will be fired twice on top of each other. It's very similar, but not identical, to "double strike". Double-layering fires the second drop right after the first one so the precision is much better than double-strike, which fires the second drop at the next pass. Mechanical error makes double-strike much less accurate than double-layering. There're a few more differences between these 2 but I'll save that for now.


> Are C1/C2 = 40/80 the same as 80/40?

No, they won't give the same color (or density). You'll get different result when you put large drop on small drop instead of small drop on large drop. Think about it. You can test that.


> The funny thing is that the patches that are bleeding are 300% ink, and the 400% patches look fine - no bleeding.

How do you notice the bleeding in 300? By noticing some banding? Sometimes more ink covers up artifacts seen in less ink.


> ProfileMaker 5.0.8 with GCR4, black start of 40, Max K of 100
>
> Illustrator and Photoshop boxes of 100C, 100M, 100Y, 100K
>
> A) Just Linearization and 3.2 (320) ink limit in Onyx, no output profile- 338 Total Ink in Preflight.
>
> B) same Linearization and 3.2 ink limit with ProfileMaker total ink limit of 320 - 308 Total Ink in Prefilight.
>
> C) same Linearization and 3.2 ink limit with ProfileMaker total ink limit of 400 - 347 Total Ink in Prefilight.

Of course, your result (kind of) shows what it should be.

A) Onyx uses its internal GCR table, which is theoretically, to convert 400 down to 320.
B) PM converts 400 down to 320 using ICC algorithm, trying keep the closet Lab color value (of 400 of your input profile) as possible. So it's different than A.
C) PM found that 347 can create the same color as 400, so it converts to 347. Keep in mind that Onyx's already convert all ink above 320 down when you printed ICC chart. PM was already fooled when it read the chart because the 400% patch in ICC chart is not really 400% anymore. Instead it's been changed by Onyx to another color (lower than 320) value. PM tried to find another equivalent of that color, which is 347 in this case. Again, this color will not really be 347 when print. It'll be converted (again) by Onyx's ink limit table to something less than 320.

I assume that for B and C you made the ICC using charts printed AFTER you set ink limit in Onyx, otherwise it'll be another story.


> Should we set ink limit in Onyx or PM?

If there's no bleeding or drying time issue in Onyx's ink limit chart, don't limit it. Set the limit in PM. This way you can create different ICC using different ink limit and can test it. After that you can choose the lowest ink limit that still produce good result. If you set ink limit too low in Onyx, you'll have to print the new chart and recreate the ICC again. Now you see which way is more flexible.

Setting ink limit in Onyx has one advantage, though. Sometimes you may want to turn off ICC - like when you want to control the exact amount of each ink channel. This way you can play around with it and will never go beyond that ink limit value.

If you set ink limit in Onyx too high and there's bleeding, the ICC you create later will have some error due to bleeding in some ICC chart's patches.

I consider the "Advance" ink limit in Onyx a godsend. It allows you to set ink limit of each channel or combination of channels separately. Each ink color has different viscosity, which makes ink limit of each channel different. You'll find this very useful when profiling poor eco-solvent ink on poor media.

[M.A.C.]

First of all, thanks alot for your long winded reply.
I appreciate your time.

> Are C1/C2 = 40/80 the same as 80/40?

No, they won't give the same color (or density). You'll get different result when you put large drop on small drop instead of small drop on large drop. Think about it. You can test that.

How do you suggest I approach restricting the double layering? I would imagine we should be restricting C2 until 0% and then restrict C1 from then on? Same for MYK obviously??

[eye4clr]

Start with both at 100 then cut into the 2 until it goes down to zero. Then start into the 1.

IOW, you would never have C1=90, C2=40. You may have C1=100, C2=45.

Restrict the lc lm at 90-100% of the 1's. So most of the time the 1's will stay at 100 and the lc lm will be 90-100 while the 2's fluctuate.

Just for redundancy, these are not different dot sizes in the context of an HP5000/5500. They are the fancy 'double layering' mentioned by torpedo. In piezo heads, they are different dot sizes and would be handled very differently.

[M.A.C.]

so for

C1 100
C2 50

would it be

lc1 90
lc2 45

or

lc1 100
lc2 35

?

[eye4clr]

I'd say C1-100/C2-50 would get lc1-90/lc2-82. Do the light inks relative to each other, not the full ink 2's. Think of it as tiered system. 2's on top, 1's next, med lc, then the lightest lc.

Honestly i have not worked with the Z series yet. So i'm unsure of the multiple light inks. But i doubt you'd go too wrong to carry the logic of the transition control that's worked very well in the 5000/5500. Someone please correct me if my ignorance is leading to bad information.

[jcuads]

Okay, in the case of the 5500 the default for Onyx is C1 and lc are 80% of C2. So for simplicity sake let's say we do a Basic Ink restriction then switch over to Advance where we'll see the 80% value of C2 as lc and C1. Of course I'm aware that some would agree that 90% works better so here we can change it if we want. Can we agree on that? Concerned about significant spikes in the readings I recently called Gretag to ask if they had any remedy for the EyeOne in the way of a polarizing filter. A tech later called me back and assured me that the key to success with ink restrictions, beyond the basics was to set the transition controls to 4 and that would remedy the spikes. I haven't had a chance to try this yet, but maybe you guys can offer comments.

[eye4clr]

you shouldn't get spikes unless the material has a surface texture. If there are abrupt spikes, the error may be in how you move the instrument. Try going a bit slower and smoother and see if that clears it up.

Setting the light inks relative to the 2 could lead to some very bad transitions from light to full inks. Since the 2 are restricted first, you may end up with low values in the 2's that would lead to very little use of the light inks. This is why the light inks should be set relative to the 1's.

If you're getting a single spike that points down and kinda looks like a stick figure of a seagull, then your light inks are set too low.