OEM/MIS/RNP/QTR Continuous smooth tone silver paper

[jag2x]

Hi all,

At the moment I have a R800 printer and about to undertake printing digi negs for Ilford Multigrade Silver paper using the normal OEM epson inkset.

If I were to produce a digi neg of just one ink such as Photo Black I am aware of the issue that a highlight regions of an image could show peppered marks (spacing of ink) such as a sky with clouds in it.
So calibration comes in, using the tool QTR.
I would need to print each color of the printer and find the blocking characteristcs on my Ilford substrate. I have the Spyder Datacolor printfiix tool to find density and Lab values to make my life easier.
Then I would create a ICC profile in QTR to break down the % of (Ilford paper)highlights to shadows needed from multiple inks to get my smooth continuous tone...

My question is that if I were to use the MIS inkset would I get a better result of continuous tone?
http://www.inksupply.com/r1800_bo.cfm
As they have a 3 set of catridges for the blacks, presumably 3 shades of blacks such as light light black, light black and dark black. Though there could be a problem with the blocking characteristics of these inks with the Silver paper?

Another question to mind, would RNP do away with the above? Would I find one blocking color that would give me a smooth continuous tone?

I never knew digital negs would be so cumbersome and the learning curve is steep with QTR but I like a challenge
Cheers
jacek

 

[Daniel Balfour]

Jacek,

Heh, well I'm glad someone likes the challenge. You can count me totally out of that one. I've been toiling with diginegs for silver-gelatin for just over a week and I've hit the same snag. I've been trying to demystify QTR (or at least gone through the motions in R. Reeder's latest essay) with no luck whatsoever. Finally I just gave up and followed his step-by-step procedure. The results were well.. eh, so so. I mean sure, I got a printable image, but I'm having a lot of problems linearizing the curve for continuous tone, thus far elusive. I have a standard T/R densitometer.

You seem to have more of a handle on the subject matter. Care to share your own process? How do you determine the "blocking ability" of a given color? How's that translate into a workflow? In my own experiments, I've simply followed Reeder's example using (Epson 3800 K3) K,C,M for darks and LK,LM,LLK for lights in a 2-part grey profile. I have of course printed the color calibration ink separation sheet but I've no clue how to use the data.

Help!

 

[sanking]

At this point in time I am using an Epson 3800 and have worked out several good QTR profiles for my alternative printing. Still, none of them is absolutely perfect and I anticipate using another half ton or so of Pictorico in tests to develop the perfect profile whenever I get back to this.

My advice to beginners with digital negatives would be to start with either Mark Nelson's PDN system or use ChartThrob with MKS' color array to determine the best blocking density for your process. This is a very direct method and can often be determined with just one or two printing. The problem with QTR is that creating a profile for best UV blocking density it is mostly trial and error and is best used with a UV densitometer, which most people don't own. After you determine the best UV blocking density it is not difficult at all to develop a good .acv curve. ChartThrob will do this easily but you must have PhotoShop CS2 or higher.

Unfortunately if you need really high UV blocking, say log 2.0 or higher, this can be hard to achieve with the methods of PDN and MKS's color array. QTR does this easily, though it requires a lot of testing. I don't know anything about the MIS inks. I suspect they would give more UV blocking density of the R800 and R1800, but will they adhere well to the OHP substrate?

Sandy King

Jacek,

Heh, well I'm glad someone likes the challenge. You can count me totally out of that one. I've been toiling with diginegs for silver-gelatin for just over a week and I've hit the same snag. I've been trying to demystify QTR (or at least gone through the motions in R. Reeder's latest essay) with no luck whatsoever. Finally I just gave up and followed his step-by-step procedure. The results were well.. eh, so so. I mean sure, I got a printable image, but I'm having a lot of problems linearizing the curve for continuous tone, thus far elusive. I have a standard T/R densitometer.

You seem to have more of a handle on the subject matter. Care to share your own process? How do you determine the "blocking ability" of a given color? How's that translate into a workflow? In my own experiments, I've simply followed Reeder's example using (Epson 3800 K3) K,C,M for darks and LK,LM,LLK for lights in a 2-part grey profile. I have of course printed the color calibration ink separation sheet but I've no clue how to use the data.

Help!

 

[Daniel Balfour]

Where does one get a "U.V. Densitometer" ?

Hmm out with the X-rite 810 I suppose.. Damn paperweight!

 

[Daniel Balfour]

Sandy,

Wait a minute...

The X-Rite 810 I have sitting in front of me measures color densities in RGB values. Does that make this thing a "U.V. Densitometer"? And if so, what would be the method to determine a curve?

 

[sanking]

The X-Rite 810 is a good color densitometer, but it does not have the proper filter to measure UV light.

Sandy

Sandy,

Wait a minute...

The X-Rite 810 I have sitting in front of me measures color densities in RGB values. Does that make this thing a "U.V. Densitometer"? And if so, what would be the method to determine a curve?

 

[Daniel Balfour]

Ok, but considering that I'm exposing to tungsten essentially, do I still need the ability to measure UV?

 

[jag2x]

Jacek,
Care to share your own process? How do you determine the "blocking ability" of a given color? How's that translate into a workflow?

Hi Daniel, Sorry I havent even undertaken any printing as yet. In regards with QTR i'm not so sure if I understand everything completely though i'll give it a go...(and probably you already know what i'm talking about.)
When you've printed your Calibration 21 step wedge for each color on a Transparency(TP) and contact printed that on your silver substrate(SS). You figure out the blocking ability of each of those inks on the SS.
You figure out with your densitometer Reflection reading of each of the squares printed on the SS. From here you get an understanding of what blocking colors on your TP are transferred across to the SS. For example say the Yellow ink that was contact printer on the SS gives you a densitometer reflection reading(on SS) of a few steps; 0.04 to 0.57.
This as I understand it would be your starting point for using this range from Highlights to the starting midtones and you'd key in the LIMIT of yellow in the profile in QTR. You'd then find the rest of the reflection values of what would continue from .057 to your DMAX of your SS. Say we only use 2 inks the Yellow and Matte black, then we create the N_OF_GRAYPARTS_= 2
and key in the Matte black and Yellow values.
As a side note there would be issues as i've stated, that there might be "HOLES" in the steps for highlights, so you need to figure out which ink gives the least amount of "HOLES" in the step?
I think that would be very basic way of using QTR, the confusion part in my opinion is when combining multiple color inks together and therefore coming up with a less "HOLES" in the step. Perhaps this is where trial and error comes in!

Another question, can we combine what we've learnt from the RNP approach of printing a HSL array and key it into QTR? Could it help us understand the colors better?

Just another idea I had, was instead of using QTR was to colourise an image in CS.
1. Invert the image to a negatve.
2. select a specific tone with the magic wand, feather it.
3. Add the desired color to that tone.
4. repeat steps 2 to 3 for the rest of the tones.
Knowing what color to add would be the tricky part...
This sort of extends Chartthrob so to speak, instead of using one color we're using multiple. Though with QTR you can control the amount of ink that is deposited on the TP, so this approach wouldn't work as good as QTR

I had printed all my TP from Imagesetters before and they were wonderful in continuous tone(well to my eye), though expensive !

 

[jag2x]

Ok, but considering that I'm exposing to tungsten essentially, do I still need the ability to measure UV?

With tungsten I doubt you would need UV. As you silver substrate might not need the UV wavelength for exposure. Though I could be wrong....

 

[jag2x]

The results were well.. eh, so so. I mean sure, I got a printable image, but I'm having a lot of problems linearizing the curve for continuous tone, thus far elusive. I have a standard T/R densitometer.

Hi Daniel, What sort of image did you end up with? Did you create a curve to linearize the tones?
Jacek

 

[jag2x]

My advice to beginners with digital negatives would be to start with either Mark Nelson's PDN system or use ChartThrob with MKS' color array to determine the best blocking density for your process.
Sandy King

Thanks for that Sandy, I intend on doing Gum once I get my head around Silver printing as there is lot less factors to worry about!
Will be looking at Mkosh's HSL and chartthrob ways of printing..cheers.
J

 

[Daniel Balfour]

Hi Daniel, What sort of image did you end up with? Did you create a curve to linearize the tones?
Jacek

I tried to linearize the tones using Gray Curve, the low-mids were muddy and the highs have no separation. Basically, this is CRAP.

If Sandy King says he's gonna have to blow "2 tons of paper" playing guessing games, imagine what the odds are for regular-Joe. For me it's been a long week, and well over $250 in ink & paper blown on worthless step tablets. Documentation for this "process", if I can even call it that, just doesn't exist. At least where Digital Negs are concerned. And I wouldn't call a couple of essays and an 8-page "user manual" documentation. This, especially given the how it's touted in Hinkel/Reeder's book, which mind you focuses primarily on the Burkholder/Curves method.

I guess your mileage may vary, but as far as I go, I think I'm about done with QTR for the time being. I'd love to give it another go if there was a more method and less madness, but I just don't have the disposable income to throw good time, ink and paper after bad.

 

[sanking]

No, if you are using tungsten light to expose silver paper you don't need to measure UV blocking density.

But you need to measure UV for all alternative type printing.

Sandy

Ok, but considering that I'm exposing to tungsten essentially, do I still need the ability to measure UV?