QTR-Quadtone RIP

So I've been following the User Guide written by Tom Moore and I've started characterizing the inks and I'm getting some strange values for my Black ink.

I'm printing on Epson Hot Press Bright using an Epson 9890 with UC K3 inks (1440 dpi | unidirectional | matte ink) and measuring density using a Colormunki Photo

All my inks EXCEPT for Ink 1 - Black show max density (lowest L value) between 95-100 %,

BUT

For (Ink 1 - Black) max density has an L value of 13.2 at the 75% level, but strangely the L value starts INCREASING as I continue measuring up to 100%.

How is this possible and what value/percentage should I be using for my ink density for the second calibration print ? 75% or 100%

Paul

The high load (high pigment particle content) MK will "clog" the paper coating sooner than the rest. As you go over what the paper can handle, the lab L value will increase (more light is reflected).

Those are high ink loads you're getting, but then I've never used that printer and inkset. Also, that dmax/low Lab L value is excellent. As you approach your MK 75 limit, you probably notice that the changes from one patch to the next are very low. Be sure they are not see-sawing up and down. You're better off at what I call the left edge of the plateau. You might also consider setting the K limit at 65 and setting the boost to 75. In that case, use 65 for the second Calibration print. I sometimes set the K ink limit at where I can no longer see the differences in normal viewing light, using the Black Boost to get to where the instrument can see the max. With the Boost, you can find tone that as needed for different paper batches and other variables without having a significant effect on the rest of the profile.

Paul

www.PaulRoark.com

On Tue, May 27, 2014 at 10:26 PM, paul.ozzello@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

So I've been following the User Guide written by Tom Moore and I've started characterizing the inks and I'm getting some strange values for my Black ink.

I'm printing on Epson Hot Press Bright using an Epson 9890 with UC K3 inks (1440 dpi | unidirectional | matte ink) and measuring density using a Colormunki Photo

All my inks EXCEPT for Ink 1 - Black show max density (lowest L value) between 95-100 %,

BUT

For (Ink 1 - Black) max density has an L value of 13.2 at the 75% level, but strangely the L value starts INCREASING as I continue measuring up to 100%.

How is this possible and what value/percentage should I be using for my ink density for the second calibration print ? 75% or 100%

Paul

When you lay down more ink than the paper can hold it tends to lie on the surface and reflect the light. Thus you often find that once the maximum ink the paper can hold has been reached the L values start to increase rather than decrease. From your figures you should set your black ink value at 75% for the second calibration print. I must say I am surprised that you make it to between 95% and 100% for the yellow, mine on a 9800 or 7880 generally run at around 35%.

David Whistance

Hi Paul, yes this ink paper combination gives really good DMax - close to 1.8, noticeably blacker than DMax of Piezography inks. The density values are not see-saw but gradually decrease continually until the 100% patch. So if I set my default ink limit to 75, should I override all the other inks to 95-100 % ? I'm still not sure I understand what the boost exactly does.

Paul

________________________________________________

Paul OZZELLO

Fine art photography
www.paulozzello.com
Tel: +1.514.451.8399

Email: paul.ozzello@...

On Wed, May 28, 2014 at 10:26 AM, Paul Roark roark.paul@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

The high load (high pigment particle content) MK will "clog" the paper coating sooner than the rest. As you go over what the paper can handle, the lab L value will increase (more light is reflected).

Those are high ink loads you9;re getting, but then I've never used that printer and inkset. Also, that dmax/low Lab L value is excellent. As you approach your MK 75 limit, you probably notice that the changes from one patch to the next are very low. Be sure they are not see-sawing up and down. You're better off at what I call the left edge of the plateau. You might also consider setting the K limit at 65 and setting the boost to 75. In that case, use 65 for the second Calibration print. I sometimes set the K ink limit at where I can no longer see the differences in normal viewing light, using the Black Boost to get to where the instrument can see the max. With the Boost, you can find tone that as needed for different paper batches and other variables without having a significant effect on the rest of the profile.

Paul

www.PaulRoark.com

On Tue, May 27, 2014 at 10:26 PM, paul.ozzello@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

So I've been following the User Guide written by Tom Moore and I've started characterizing the inks and I'm getting some strange values for my Black ink.

I'm printing on Epson Hot Press Bright using an Epson 9890 with UC K3 inks (1440 dpi | unidirectional | matte ink) and measuring density using a Colormunki Photo

All my inks EXCEPT for Ink 1 - Black show max density (lowest L value) between 95-100 %,

BUT

For (Ink 1 - Black) max density has an L value of 13.2 at the 75% level, but strangely the L value starts INCREASING as I continue measuring up to 100%.

How is this possible and what value/percentage should I be using for my ink density for the second calibration print ? 75% or 100%

Paul