Digital BW, The Print

Since I've been kind of out of the loop for a while, thought I better ask and see if anyone knows of any new and better spectro's out there. I have an issue where I can not accurately measure an ink because it is more dense than the current stuff will measure with any degree of accuracy. This is less than a LAB L of 1, getting measurements of anywhere between .22L to .37L which all goes to somewhere around a density of 3.0D. Since all my tools only produce enough light to measure 2.5D (so say the specs), I know this can not be entirely correct. Checked it with two different spectros, didn't feel like dragging out the other two for more checking. All this measured with the "black" backgound on my Spectroscan or on the white board for my Pulse. Surprising that even on the white board this stuff is pretty much a black hole.

Anyone have a lab grade spectro that can measure this dark and would be willing to measure a few patches?

And please do not ask about the ink, I can not release details yet. When I can you will have a decent report. Test targets go in the window tomorrow to see what happens. Paper is some sort of Epson that came with my RX680 or a cheapo Kodak glossy so nothing really special.

On May 14, 2009, at 10:53 PM, Greg wrote:

> Since I've been kind of out of the loop for a while, thought I  
> better ask and see if anyone knows of any new and better spectro's  
> out there. I have an issue where I can not accurately measure an ink  
> because it is more dense than the current stuff will measure with  
> any degree of accuracy. This is less than a LAB L of 1, getting  
> measurements of anywhere between .22L to .37L which all goes to  
> somewhere around a density of 3.0D. Since all my tools only produce  
> enough light to measure 2.5D (so say the specs), I know this can not  
> be entirely correct. Checked it with two different spectros, didn't  
> feel like dragging out the other two for more checking. All this  
> measured with the "black" backgound on my Spectroscan or on the  
> white board for my Pulse. Surprising that even on the white board  
> this stuff is pretty much a black hole.
>
> Anyone have a lab grade spectro that can measure this dark and would  
> be willing to measure a few patches?

You are asking either the impossible, or the very expensive, depending  
on just what degree of improvement you are looking for.

C. David Tobie
Global Product Technology Manager
Digital Imaging & Home Theater
CDTobie@...


  ----------


Datacolor
www.datacolor.com/Spyder3



[Non-text portions of this message have been removed]

> > ... I can not accurately measure an ink  
> > because it is more dense than the current stuff will 
> > measure with any degree of accuracy. ... LAB L of 1, ...
> > somewhere around a density of 3.0D ...
> > this stuff is pretty much a black hole.

> You are asking either the impossible, or the very expensive, ...

Some of us were also getting 3.0+ density readings with the coating workflows that we experimented with -- particularly running the glossy prints through the printer a second time to apply an overcoat of glop.  I think the affordable spectros' inability to measure accurately at those levels correlates well with our eyes' inability to see any difference from about dmax 2.5 to 3 -- particularly in typical display situations where reflections block our ability to see into the deep blacks on glossy paper.  I'd keep an eye on the pizza wheel marks and whether they are exacerbated by whatever you're doing to reach those numbers.  I found the post-printing glop application made the problem worse, for example.

Paul
www.PaulRoark.com

On May 15, 2009, at 11:40 AM, pr_roark wrote:

> Some of us were also getting 3.0+ density readings with the coating  
> workflows that we experimented with -- particularly running the  
> glossy prints through the printer a second time to apply an overcoat  
> of glop.  I think the affordable spectros' inability to measure  
> accurately at those levels correlates well with our eyes' inability  
> to see any difference from about dmax 2.5 to 3 -- particularly in  
> typical display situations where reflections block our ability to  
> see into the deep blacks on glossy paper.  I'd keep an eye on the  
> pizza wheel marks and whether they are exacerbated by whatever  
> you're doing to reach those numbers.  I found the post-printing glop  
> application made the problem worse, for example.



Right. But we have devices costing more than a small car in our optics  
lab, and they don't make it to 3.0 either, they just make it a bit  
further beyond 2.5... which is why I said impossible or expensive,  
depending on the spec...

C. David Tobie
Global Product Technology Manager
Digital Imaging & Home Theater
CDTobie@...


  ----------


Datacolor
www.datacolor.com/Spyder3



[Non-text portions of this message have been removed]

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, C D Tobie <CDTobie@...> wrote:

> 
> 
> Right. But we have devices costing more than a small car in our optics  
> lab, and they don't make it to 3.0 either, they just make it a bit  
> further beyond 2.5... which is why I said impossible or expensive,  
> depending on the spec...
> 


Ok, that answers that question then, I was afraid that it might not be possible with current technologies to produce something that costs less than a house that can measure this sort of density. I know that what I'm seeing is really just bouncing along the noise floor of the spectros but it is still pretty impressive. Wish I had a light trap that used to be used for black calibration on some of the older devices to see what it measured.

And this is simply print, dry, measure and black down into the noise floor of the spectro.

Oddly it doesn't do very well on the Hawk Mountain papers. ALl three inks only had about an L=18-20, two of the inks were Claria and the dye ink that Ink Republic ships with their CIS. Guess it must be the paper, I'll have to get a few other "fine art" papers to try before I switch to a new pigment/dye hybrid that I need to try.

We sell a light trap that can be measured with a spectro; it's on our  
website under the name SpyderCube. I use it regularly to take absolute  
black measurements with my spectros.

C. D. Tobie
Global Product Technology Mngr.
Digital Imaging & Home Theater
Datacolor.com
CDTobie@...

On May 15, 2009, at 6:03 PM, "Greg" <dfaprinting@...> wrote:

> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, C D Tobie  
> <CDTobie@...> wrote:
>
>>
>>
>> Right. But we have devices costing more than a small car in our  
>> optics
>> lab, and they don't make it to 3.0 either, they just make it a bit
>> further beyond 2.5... which is why I said impossible or expensive,
>> depending on the spec...
>>
>
>
> Ok, that answers that question then, I was afraid that it might not  
> be possible with current technologies to produce something that  
> costs less than a house that can measure this sort of density. I  
> know that what I'm seeing is really just bouncing along the noise  
> floor of the spectros but it is still pretty impressive. Wish I had  
> a light trap that used to be used for black calibration on some of  
> the older devices to see what it measured.
>
> And this is simply print, dry, measure and black down into the noise  
> floor of the spectro.
>
> Oddly it doesn't do very well on the Hawk Mountain papers. ALl three  
> inks only had about an L=18-20, two of the inks were Claria and the  
> dye ink that Ink Republic ships with their CIS. Guess it must be the  
> paper, I'll have to get a few other "fine art" papers to try before  
> I switch to a new pigment/dye hybrid that I need to try.
>
>
>
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--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Cdtobie <CDTobie@...> wrote:
>
> We sell a light trap that can be measured with a spectro; it's on our  
> website under the name SpyderCube. I use it regularly to take absolute  
> black measurements with my spectros.
> 


Thanks I may pick one of those up. I've seen many different tonal control devices like this, but they were all kind of bulky.

For spectro use, do you stick the end of the spectro in the hole and measure.

On May 16, 2009, at 11:20 AM, Greg wrote:

> Thanks I may pick one of those up. I've seen many different tonal  
> control devices like this, but they were all kind of bulky.

Well, this is non-bulky, and has a number of other uses to justify its  
existance. <G>
>
> For spectro use, do you stick the end of the spectro in the hole and  
> measure.

Yup, assuming a somewhat tapered, round tip, you can insert it firmly  
into the black trip, and measure. Works great with our spectros, well  
with the EyeOne; haven't tried the (now outdated) Pulse.

C. David Tobie
Global Product Technology Manager
Digital Imaging & Home Theater
CDTobie@...


  ----------


Datacolor
www.datacolor.com/Spyder3



[Non-text portions of this message have been removed]