- Joined
- Sep 14, 2002
- Messages
- 27
M-- As you may be able to tell, I only know enough about QTR to make one set of actions work. I definitely do not know all the bells and whistles that are available in it. When I use Gray Curve to finalize tonal linearization I use paired numbers typed in between quotes. I believe you are right that gray curve can use a .acv curve. But, as I tried to explain in an earlier post to Helen Bach, to work for printing negatives the number pairs must first be transposed from positive space to negative space and then inverted. That is what I have done for the number pairs in all the QTR profiles I have posted here.
When I say seven inks, I am talking about the seven Ultrachrome inks used by my Epson 4000 (and by the 2200 as well) Matte Black, Light Black, Cyan, Light Cyan, Magenta, Light Magenta, and Yellow.
Ron Reeder
mkochsch -- I am certain there are many ways of obtaining your goal. I append a profile I recently wrote for the Epson 4000 showing how I solved the problem.I'm struggling with the decision as to how to start my ink setup if I'm not using either Black (K) or Light Black (Lt. K) in my workflow since most examples I've seen always use the K or Lt. K as the primary starting colour.
For example, should I use C, M, Y in "Gray Ink" mode and then use "Copy Curve From" mode on Lt. C and Lt. M to point those inks at C and M respectively? Maybe I should just use Yellow as my "Gray Ink" and then curve from there with the others?
When I do my linearization for OHP should I apply the same ACV file to the three primaries? How? Will applying it just once in the "Gray Curve" tab do the same to all three primaries?
mkochsch -- I am certain there are many ways of obtaining your goal. I append a profile I recently wrote for the Epson 4000 showing how I solved the problem.
Cheers, Ron Reeder
Kees--Ron, what color does your negative have with this profile? When you use a partitioned workflow for K and LK, C and LC, M and LM and not for Y, because there is no light Y, the negative gets a CM hue in the lighter tones I noticed. This might be more visible whithout K and LK. One way to get a more neutral BW print is by not partitioning and copy_curve the same curve for every color.
Attached is an example file to explain what I am doing. I think the LK can indeed be added without any problem. This gives a higher overal density. To change the hue of the negative it is possible to take down ink limits for each individual color or pairs of colors.
regards,
kees
mkochsch-- I feel your pain. I am sorry that I am not much help with the PC specific problems (being one of the Mac crowd, you know). Are you aware of the Yahoo chat group dedicated to QTR problems? Go to the Quadtone RIP overview web page and click on Support. Maybe someone in that group can help. Good luck, Ron ReederI'm experiencing mounting obstacles in my quest to integrate QuadToneRip into my digital negative workflow:
If there is a way to fix this I'd be happy to give it a go again.
Did you make your own QTR curves too? When you download QTR there is a Curvedesign folder included.
The green (CY) negatives have most contrast, Magenta-Yellow (MY) has a bit less contrast and purple CM is low contrast. You can mix in some extra yellow or magenta to finetune from the driver where you can choose two profiles and mix them.
Here is an example of my CM inkdescriptor file: CM.txt
I use the normal ink description for the first inkcolor and the toner description position for the other.
Maybe a windows QTR user can tell if this works the same on windows.
Hope this gets you on the way!
kees
Something's wrong with the Windows version of QTR -- maybe. I bring in these files and they work OK if I don't open them with the curve creator but as soon as I do all the "copy curve = C" gets changed to K or Lt K. Hmm. In fact anytime I try to make a No K profile it changes back to K from whatever I've set the copy curve to. I think possibly an incompatibility between OS's. Anyone else trying to use the Windows version experiencing these issues?
But you can open the Max file, which is a text, in the QTRgui and it will convert it to a .qidf profile when you save it.
Also, the curve creator in the gui is a tab, and you can cut and paste the .txt file line created on the mac version directly into the space in that tab. You can open the created .qidf file directly in MS word, modify it, and reload it in QTRgui. Or you can send the file to a Mac user and they can open it as a txt file and use it in QTR.
There are some options available in the gui it seems that are not apparent when you open the file as a txt file in PC or Mac. For example, there are tone curves one and two, which can be ignored. The graphing features of the gui make it very useful for gauging how changes would affect your negative.
Mike
Don,
That is amazing that they restored the church. It was amazing when I photographed it - I photographed it on December 29th 1999. My girlfriend (now wife) and I stayed at LuLu's trailer and rented a car from them. It was a remarkable couple of days. Do you know when they restored it? The back end was falling off, and the porch had caved in.
Mike
Don,
I am trying to remember the name of the photographer from Texas who had photographed (with 4x5) there - both the people and the land. He printed on Forte warm tone, and the prints were gorgeous.
Maybe we should try to have a free workshop there before there is too much more change. In any case I will have to try to go there this Feb. and photograph.
Mike
Ah, a subject dear to my heart... I'll expand on this a bit.Hi,
We talked about using QTR for digital negatives and I noticed that there are four (or maybe more) different approaches. I am trying to list them here:
Yes, QTR handles the curves in a better than 8 bit fashion, although if memory serves, it's 14 bit, to allow some overhead.1. QTR BW workflow with quad black inks
This is what QTR was made for. You have to use a dedicated printer with black and grey inks or one of the newer K3 printers. Third party inksets are sold by MIS or Cone and others.
Each grey ink overlaps the previous and this can be controlled in the inkdescriptor file. A no K, only grey, approach is also possible. Process related density range can be controlled by setting ink limits. Process related correction/linearization curves can be specified in the gray_curve setting or applied in photoshop. (Note: does QTR handle these curves in 16 bit? If not, it is probably better to keep using them in photoshop on 16bit files)
A quite satisfactory approach, although it will result in more white speckles in light tones on the print.2. QTR BW workflow with K and LK in a printer with color inks.
As I understand Ron correctly, and after looking at his 2200 Pd and silver sample files, in his workflow only K and LK are used in combination with ink limit settings for density range control. All other inks are not used by specifying them as 'unused' or setting inklimits to zero. As an only grey approach it is not very different from the first approach but it uses only two inks.
This will work a lot better if you print a QTR calibration pattern, print that pattern onto platinum, and use it to determine the ink order based ont eh UV blocking ability of each of the colors of Epson ink. The resultant negative will look very strange, but it will work very well. As I recall, full strength magenta falls in between K and LK and "fixes" the speckles in light tones quite well.3. QTR BW workflow with all (color) inks.
This workflow uses all inks with or without K an LK to print a BW negative with all inks. Default ink limit settings control negative densitity range.
Ron's earlier example files are using copy_curve to copy and set values for each color. But individual values for each ink after measuring the inkseparation print can be set in the descriptor file also.
OK, this one I've honestly not seen before.4. QTR colorized negatives
This is a different approach and maybe combines the best of two worlds. Here the process related density range is achieved by spectral density and finetuned by ink limit settings. For each CMY color and/or two color combinations CM, CY, MY a monochrome QTR profile is made. All other inks are set to unused. CY gives a high contrast range suitable for long scale processes like salt or albumen printing. CM gives a low contrast suitable for gum printing. Contrast control and finetuning can be done by mixing two QTR-curves or by taking down inklimits (or both).
That's an understatement.This method would work even better with a ternary CMY calibration file of some sort to choose the right color for each process.
What approach gives the best results is difficult to say. When density range has to be very long, a spectral density negative might be the way to go.
To get the smoothest negative possible probably asks for a print with as many inks as possible. Inks that behave differently (K) than others (colors, greys) can be problematic so an 'all colors, no K' BW approach might be interesting. When using K2 K3 inksets a toner color can be mixed in for density range control.
And there's allways the printing substrate that has a big influence on the density range and smoothness of the negative. Different printers and inksets of course too.
Another important advantage is that the carbon black inks have virtually the same density to UV as they do to visible light, just like a regular silver negative. So densitometers and sensiometric curves work. Because the density is the same to blue and green light, multi-grade papers work with their normal filtration.
And the last important advantage is that you can "read" these negatives. I've worked with all those weird "multchromic" negatives, and they just are so much work to visualize.
My own workflow uses five dilutions of black for digital negatives on one of my Epson 2200 machines. It's loaded with an inkset I call "Wiz7" (I have a tendency to name things after myself).
100% MIS "Eboni" for matte black
100% MIS PKN ("neutral" photo black, cooler than Epson's photo black)
32% PKN
10% PKN
3.2% PKN
1% PKN
MIS "glop" (a clear varnish that can be used to fill in the uninked areas of a B&W print, or applied to the whole print as an "overcoat").
For digital negatives, I print with the 5 dilutions of PKN.
For glossy prints, 5 PKN and glop
This will work a lot better if you print a QTR calibration pattern, print that pattern onto platinum, and use it to determine the ink order based ont eh UV blocking ability of each of the colors of Epson ink. The resultant negative will look very strange, but it will work very well. As I recall, full strength magenta falls in between K and LK and "fixes" the speckles in light tones quite well.
Don,Whiz,
Exactly. Because densitometers don't tell the whole story. You may get your curves perfect, whether it's with densitometers, software like PDN, or lots of work, like Burkholder, and get a print with a great match to the screen, or a great match to your vision. Then you put it in a different light, or put it behind glass (you have any idea how much DMAX glass steals?) and you decide you need to boodt or decrease the contrast.So why is this important? Are you suggesting that you will change the filtration once a specific curve is calibrated for a specific contrast setting?
Again, because you may change dang near any part of the process, and the ability to read a negative can tell you "hey, though I created this negative for multigrade, it looks like it may also work for lith", or "that one I made for AZO is never going to work for platinum, have to make a separate one for that process..."Why do they need to be "read" at all? The negative is going to be contact printed for a specific time with no dodging and burning.
Maybe so, but what I'm doing works pretty well for me, my customers like it, and my students like it.It sounds to me that you are make printing digital negatives and ink jet prints way too complicated.
Once you've printed the chart, you can then look at each ink as a different shade of gray. You just look at your darkroom print to determine ink is the darkest (which will be photo black) then the next darkest (probably cyan) and so on, setting QTR up as if it were a seven shade of gray set, following the directions in the QTR manual for building a profile. The trick is to invert the print densities, because QTR isn't designed for negatives, and you have to make the profile generator think you've got positives...I've thought of printing the ink seperation test to determine the UV blocking when printed by QTR. Can you explain what you mean by ink order?
Another important advantage is that the carbon black inks have virtually the same density to UV as they do to visible light, just like a regular silver negative. So densitometers and sensiometric curves work. Because the density is the same to blue and green light, multi-grade papers work with their normal filtration.
One other reason why it's "important"...So why is this important? Are you suggesting that you will change the filtration once a specific curve is calibrated for a specific contrast setting?
I'll assume you meant no insult, but a "wiz" is someone who's good at something. Short for a "wizard". Around here, to "whiz" is to urinate.
There's also the issue that, because the two layers of multigrade papers are sensitive to different colors, negatives with grays made up of multiple color inks "speckle" more than negatives with pure carbon black inks.
Again, because you may change dang near any part of the process, and the ability to read a negative can tell you "hey, though I created this negative for multigrade, it looks like it may also work for lith", or "that one I made for AZO is never going to work for platinum, have to make a separate one for that process..."
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?