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The limits of working with QTR

The limits of working with QTR

2017-09-01 by skapuskar@...

QTR is a great software, especially in conjunction with Print Tool. Steep learning curve, but it is worth it.
I have been using it for many years now, it took me some time to get used to it's potential and I'm sure that there are still things to discover, but it has definitely become essential in my digital workflow.
The past weeks I have been working on 3 different projects, improving my digital negatives for carbon transfer printing, creating digital negatives for silver baryta printing, and making profiles for digital inkjet prints.

The latter was the simplest, and the obtained profile was spot on.

More time involving was the negative creation for silver prints and carbon transfer. Whereas the profile creation for inkjet works in a strict mathematical fashion, it is not so the case with alternative chemical processes. The inkjet profile creation is a straight forward linear process, you start with a base curve, apply a grey curve correction to mathematically evenly space the tonal values, then you linearize the output to obtain a smooth gamma corrected curve that results in an evenly spaced appearance to the human eye.

In the case of making digital negatives for alternative processes, unfortunately, the same procedure does not give the same predictable results. The fact that chemical processes do not follow a linear behaviour, sets the limits of QTR, in other words, this is not a QTR issue, it is the non-linear behaviour of the processes that limit QTR from giving you that perfect profile, so a lot of trial and error is required to obtain a fair profile that works for your specific process.

Mainly, my biggest difficulties in most cases were to get smooth transitions in the highlights. In my trials, the limiting factor with negatives for silver printing was the typical paper inertia, that is, it takes a certain amount of exposure to the paper before initial development would show. In the case of carbon transfer (which is a fairly linear process), the self masking properties of the sensitizer concentration would cause non-linear behaviour in the highlights.
Those are only a few elements that are specific to many processes and that QTR can not take into account, no blame.

Just sharing some thoughts...


Sidney

Re: The limits of working with QTR

2017-09-02 by sanking@...

In the case of making digital negatives for alternative processes, unfortunately, the same procedure does not give the same predictable results. The fact that chemical processes do not follow a linear behaviour, sets the limits of QTR, in other words, this is not a QTR issue, it is the non-linear behaviour of the processes that limit QTR from giving you that perfect profile, so a lot of trial and error is required to obtain a fair profile that works for your specific proces


Sidney,

Interesting post, and your experience serves to emphasize the importance of establishing density range requirements for the alternative process that reflect as closely as possible the exposure scale characteristics of the process, especially where POP/self-making is involved, as it is with carbon transfer and several other alternative processes. If one tries to force a correction curve on a profile where the DR of the digital negative is not closely matched to the ES of the process, the result will be a very abrupt correction curve that will cause digital noise and prevent smooth transitions of tones. In cases where the DR and ES are closely matched a correction curve applied with in a QTR profile will by necessity be relatively smooth, which assured a smooth transition even with self masking processes.

The other big issue with smoothness is that it is highly dependent on the use of inks are close in UV transmission blocking and similar spectral response, especially in the critical area of the negative shadow densities, which are converted into print highlight densities.

Sandy

Re: The limits of working with QTR

2017-09-02 by richard@...

Sidney,

you might want to take a look at my two digital negative systems. The QuickCurve system is for UCK3 printers, and the QuadToneProfiler Pro DN system is something I released just a few days ago for profiles with more than 4 gray inks (and insets that don't use color inks at all). I came up with a way of partitioning the grayscale that doesn't use qidf files or the QTR install command to generate the quad curves so everything takes on a much smoother curve, and does not require such an aggressive correction curve in the linearization step.

Here are some links:




I have not been able to test every process under the sun (some pun intended) but in theory, the approach is flexible enough to work with any process. I hope to get my feet wet with carbon printing this winter, and then dive back into salt printing on gelatin-silver paper again to test out these systems and start to build better starter curves for different processes to use in future updates.

Hope that helps,
Richard Boutwell

http://www.richardboutwell.com/

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-02 by forums@walkerblackwell.com

To add to the density requirement variables, one must also consider the spectral range of the the UV tube/light source that is applied, the other darkroom and chemical conditions of the coating (restrainer, not restrainer, POP v dev, etc), how far the coating has gone into the paper, the paper’s sizing or lack there-of, brush vs rod, etc. All of this has an effect on the (specifically) highlight noise and stability from print to print and process to process. There is no standard here due to the infinite variables at play from one person and their darkroom process to another. More industry standard process (Ilford MG IV + Bes.23c + sprint dev) maybe could have some standards applied (indeed, Kodak has a set of density slops for their negs which are standards) but hand processes get wonky. 

I have found the best way to make a good negative is to do four things:

1. Use many monochrome inks (similar UV response from ink to ink) that are overlapped significantly in the dense range.
2. Keep the TIL even throughout the range of the negative to ensure the same bit-depth response from highlight to shadow and to allow for big stretches of the curves in shadows, mid, and highlight. This way 1 master curve will be able to print all processes from gum to salt.
3. Use OHP Ultra Premium. This is the only film that can take the ink that can allow for stable highlights.
4. Do some tricks to make the darkroom printed target act like a normal inkjet printed target. 

We did all this in PiezoDN (for about all the current epson printers besides the SureColors which we are doing something else for).  There is really no need to mess around with building new curves unless you want to mess around making your own ink-set (which some do, not faulting them). The key is to have a workflow where you can quickly and consistently get to linear printed values without noise in highlights and then be able to optionally apply a profile for screen to print contrast match if you feel like it (or don’t feel like soft proofing with a preserve RGB number workflow). That’s exactly what PiezoDN does. It’s as easy as linearizing any other curve without the initial developmental steps. And it works for literally every alt proc besides the ones that need more intense BITE like gravure (we are working on that).

Best,
Walker
Show quoted textHide quoted text
> On Sep 2, 2017, at 12:10 PM, sanking@clemson.edu [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> In the case of making digital negatives for alternative processes, unfortunately, the same procedure does not give the same predictable results. The fact that chemical processes do not follow a linear behaviour, sets the limits of QTR, in other words, this is not a QTR issue, it is the non-linear behaviour of the processes that limit QTR from giving you that perfect profile, so a lot of trial and error is required to obtain a fair profile that works for your specific proces
> 
> 
> Sidney,
> 
> Interesting post, and your experience serves to emphasize the importance of establishing density range requirements for the alternative process that reflect as closely as possible the exposure scale characteristics of the process, especially where POP/self-making is involved,  as it is with carbon transfer and several other alternative processes. If one tries to force a correction curve on a profile where the DR of the digital negative is not closely matched to the ES of the process, the result will be a very abrupt correction curve that will cause digital noise and prevent smooth transitions of tones. In cases where the DR and ES are closely matched a correction curve applied with in a QTR profile will by necessity be relatively smooth, which assured a smooth transition even with self masking processes.
> 
> The other big issue with smoothness is that it is highly dependent on the use of inks are close in UV transmission blocking and similar spectral response, especially in the critical area of the negative shadow densities, which are converted into print highlight densities. 
> 
> Sandy
> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by Jon Goodman

Please what are "TIL" and "BITE" acronyms for?
Jon

Sent from my iPad
Show quoted textHide quoted text
> On Sep 2, 2017, at 6:49 PM, 'forums@...' forums@walkerblackwell.com [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> To add to the density requirement variables, one must also consider the spectral range of the the UV tube/light source that is applied, the other darkroom and chemical conditions of the coating (restrainer, not restrainer, POP v dev, etc), how far the coating has gone into the paper, the paper’s sizing or lack there-of, brush vs rod, etc. All of this has an effect on the (specifically) highlight noise and stability from print to print and process to process. There is no standard here due to the infinite variables at play from one person and their darkroom process to another. More industry standard process (Ilford MG IV + Bes.23c + sprint dev) maybe could have some standards applied (indeed, Kodak has a set of density slops for their negs which are standards) but hand processes get wonky. 
> 
> 
> I have found the best way to make a good negative is to do four things:
> 
> 1. Use many monochrome inks (similar UV response from ink to ink) that are overlapped significantly in the dense range.
> 2. Keep the TIL even throughout the range of the negative to ensure the same bit-depth response from highlight to shadow and to allow for big stretches of the curves in shadows, mid, and highlight. This way 1 master curve will be able to print all processes from gum to salt.
> 3. Use OHP Ultra Premium. This is the only film that can take the ink that can allow for stable highlights.
> 4. Do some tricks to make the darkroom printed target act like a normal inkjet printed target. 
> 
> We did all this in PiezoDN (for about all the current epson printers besides the SureColors which we are doing something else for).  There is really no need to mess around with building new curves unless you want to mess around making your own ink-set (which some do, not faulting them). The key is to have a workflow where you can quickly and consistently get to linear printed values without noise in highlights and then be able to optionally apply a profile for screen to print contrast match if you feel like it (or don’t feel like soft proofing with a preserve RGB number workflow). That’s exactly what PiezoDN does. It’s as easy as linearizing any other curve without the initial developmental steps. And it works for literally every alt proc besides the ones that need more intense BITE like gravure (we are working on that).
> 
> Best,
> Walker
> 
> 
> 
>> On Sep 2, 2017, at 12:10 PM, sanking@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
>> 
>> In the case of making digital negatives for alternative processes, unfortunately, the same procedure does not give the same predictable results. The fact that chemical processes do not follow a linear behaviour, sets the limits of QTR, in other words, this is not a QTR issue, it is the non-linear behaviour of the processes that limit QTR from giving you that perfect profile, so a lot of trial and error is required to obtain a fair profile that works for your specific proces
>> 
>> 
>> Sidney,
>> 
>> Interesting post, and your experience serves to emphasize the importance of establishing density range requirements for the alternative process that reflect as closely as possible the exposure scale characteristics of the process, especially where POP/self-making is involved,  as it is with carbon transfer and several other alternative processes. If one tries to force a correction curve on a profile where the DR of the digital negative is not closely matched to the ES of the process, the result will be a very abrupt correction curve that will cause digital noise and prevent smooth transitions of tones. In cases where the DR and ES are closely matched a correction curve applied with in a QTR profile will by necessity be relatively smooth, which assured a smooth transition even with self masking processes.
>> 
>> The other big issue with smoothness is that it is highly dependent on the use of inks are close in UV transmission blocking and similar spectral response, especially in the critical area of the negative shadow densities, which are converted into print highlight densities. 
>> 
>> Sandy
>> 
> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by forums@walkerblackwell.com

TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).

Best and cheers,
Walker
Show quoted textHide quoted text
> On Sep 3, 2017, at 9:31 AM, Jon Goodman jon@jgoodgravure.com [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> 
> Please what are "TIL" and "BITE" acronyms for?
> Jon
> 
> Sent from my iPad
> 
> On Sep 2, 2017, at 6:49 PM, 'forums@... <mailto:forums@walkerblackwell.com>' forums@... <mailto:forums@...> [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP@yahoogroups.com>> wrote:
> 
>>  
>> To add to the density requirement variables, one must also consider the spectral range of the the UV tube/light source that is applied, the other darkroom and chemical conditions of the coating (restrainer, not restrainer, POP v dev, etc), how far the coating has gone into the paper, the paper’s sizing or lack there-of, brush vs rod, etc. All of this has an effect on the (specifically) highlight noise and stability from print to print and process to process. There is no standard here due to the infinite variables at play from one person and their darkroom process to another. More industry standard process (Ilford MG IV + Bes.23c + sprint dev) maybe could have some standards applied (indeed, Kodak has a set of density slops for their negs which are standards) but hand processes get wonky. 
>> 
>> 
>> I have found the best way to make a good negative is to do four things:
>> 
>> 1. Use many monochrome inks (similar UV response from ink to ink) that are overlapped significantly in the dense range.
>> 2. Keep the TIL even throughout the range of the negative to ensure the same bit-depth response from highlight to shadow and to allow for big stretches of the curves in shadows, mid, and highlight. This way 1 master curve will be able to print all processes from gum to salt.
>> 3. Use OHP Ultra Premium. This is the only film that can take the ink that can allow for stable highlights.
>> 4. Do some tricks to make the darkroom printed target act like a normal inkjet printed target. 
>> 
>> We did all this in PiezoDN (for about all the current epson printers besides the SureColors which we are doing something else for).  There is really no need to mess around with building new curves unless you want to mess around making your own ink-set (which some do, not faulting them). The key is to have a workflow where you can quickly and consistently get to linear printed values without noise in highlights and then be able to optionally apply a profile for screen to print contrast match if you feel like it (or don’t feel like soft proofing with a preserve RGB number workflow). That’s exactly what PiezoDN does. It’s as easy as linearizing any other curve without the initial developmental steps. And it works for literally every alt proc besides the ones that need more intense BITE like gravure (we are working on that).
>> 
>> Best,
>> Walker
>> 
>> 
>> 
>>> On Sep 2, 2017, at 12:10 PM, sanking@clemson.edu <mailto:sanking@...> [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP@yahoogroups.com>> wrote:
>>> 
>>> In the case of making digital negatives for alternative processes, unfortunately, the same procedure does not give the same predictable results. The fact that chemical processes do not follow a linear behaviour, sets the limits of QTR, in other words, this is not a QTR issue, it is the non-linear behaviour of the processes that limit QTR from giving you that perfect profile, so a lot of trial and error is required to obtain a fair profile that works for your specific proces
>>> 
>>> 
>>> Sidney,
>>> 
>>> Interesting post, and your experience serves to emphasize the importance of establishing density range requirements for the alternative process that reflect as closely as possible the exposure scale characteristics of the process, especially where POP/self-making is involved,  as it is with carbon transfer and several other alternative processes. If one tries to force a correction curve on a profile where the DR of the digital negative is not closely matched to the ES of the process, the result will be a very abrupt correction curve that will cause digital noise and prevent smooth transitions of tones. In cases where the DR and ES are closely matched a correction curve applied with in a QTR profile will by necessity be relatively smooth, which assured a smooth transition even with self masking processes.
>>> 
>>> The other big issue with smoothness is that it is highly dependent on the use of inks are close in UV transmission blocking and similar spectral response, especially in the critical area of the negative shadow densities, which are converted into print highlight densities. 
>>> 
>>> Sandy
>>> 
>> 
>> 
> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by forums@walkerblackwell.com

>> "BITE" acronyms for?


Or more specifically the bite is simply referring to the divits and the “bite size” is their width, “bite depth” their depth, etc.  It all gets wrapped under one term I guess is how I see it. I’m no expert at all so others should correct me here if I’m wrong . . .

Best,
Walker
Show quoted textHide quoted text
> On Sep 3, 2017, at 9:34 AM, forums@... wrote:
> 
> TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).
> 
> Best and cheers,
> Walker
>> .
>>  
>> 
>> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by Jon Goodman

Thanks. Wouldn't "Bite" be provided by either the gravure screen or aquatint. The gravure screen is a separate exposure, the aquatint is a physical entity. I am not clear how the gravure positive is made differently in those terms. The screening inherent in inkjet film has never seemed to have any noticeable difference from analog film.
Jon

Sent from my iPad
Show quoted textHide quoted text
> On Sep 3, 2017, at 11:35 AM, 'forums@...' forums@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
>>> "BITE" acronyms for?
> 
> 
> Or more specifically the bite is simply referring to the divits and the “bite size” is their width, “bite depth” their depth, etc.  It all gets wrapped under one term I guess is how I see it. I’m no expert at all so others should correct me here if I’m wrong . . .
> 
> Best,
> Walker
> 
> 
>> On Sep 3, 2017, at 9:34 AM, forums@... wrote:
>> 
>> TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).
>> 
>> Best and cheers,
>> Walker
>>> .
>>>  
>>> 
>> 
> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by forums@walkerblackwell.com

Make a “noisy” negative using a specific dither. Or print directly onto a polymer plate with 1 channel using a slightly different dither.

One way to do this is the print directly onto the plate with Matte black ink using the Epson (or QTR) driver and only 1 channel of ink. This creates the proper amount of pure dots. We are working on something that will be a bit more ideal for that but it is competing with lots of other things on our plates (sorry for the pun).

I’m sure Don Messick could elaborate if he was on this list.

Best,
Walker
Show quoted textHide quoted text
> On Sep 3, 2017, at 12:16 PM, Jon Goodman jon@... [QuadtoneRIP] <QuadtoneRIP@...m> wrote:
> 
> 
> Thanks. Wouldn't "Bite" be provided by either the gravure screen or aquatint. The gravure screen is a separate exposure, the aquatint is a physical entity. I am not clear how the gravure positive is made differently in those terms. The screening inherent in inkjet film has never seemed to have any noticeable difference from analog film.
> Jon
> 
> Sent from my iPad
> 
> On Sep 3, 2017, at 11:35 AM, 'forums@... <mailto:forums@...>' forums@... <mailto:forums@...> [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP@yahoogroups.com>> wrote:
> 
>>  
>> 
>>>> "BITE" acronyms for?
>> 
>> 
>> Or more specifically the bite is simply referring to the divits and the “bite size” is their width, “bite depth” their depth, etc.  It all gets wrapped under one term I guess is how I see it. I’m no expert at all so others should correct me here if I’m wrong . . .
>> 
>> Best,
>> Walker
>> 
>> 
>>> On Sep 3, 2017, at 9:34 AM, forums@... <mailto:forums@...> wrote:
>>> 
>>> TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).
>>> 
>>> Best and cheers,
>>> Walker
>>>> .
>>>>  
>>>> 
>>> 
>> 
>> 
> 
>

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by Alan Vlach

I've had success printing direct to plate using QTR on the 3800. You have to use MK in the blend. I also used yellow, cyan, light cyan and light black. When I tried the profile on the 3880 and P800 I started getting some odd spotting on the plates. Don't know if there was some incompatibility with the HD inks and the polymer but is was a consistent problem. For those printers I use an aquatint screen first to put the bite into the plate and have a calibration using only cyan ink to print direct to plate.

I had tried using PK inks in the calibration without success until Stig Stassen turned me onto the MK trick.

Alan
Show quoted textHide quoted text
> On Sep 3, 2017, at 12:23 PM, 'forums@walkerblackwell.com' forums@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> Make a “noisy” negative using a specific dither. Or print directly onto a polymer plate with 1 channel using a slightly different dither.
> 
> One way to do this is the print directly onto the plate with Matte black ink using the Epson (or QTR) driver and only 1 channel of ink. This creates the proper amount of pure dots. We are working on something that will be a bit more ideal for that but it is competing with lots of other things on our plates (sorry for the pun).
> 
> I’m sure Don Messick could elaborate if he was on this list.
> 
> Best,
> Walker
> 
> 
>> On Sep 3, 2017, at 12:16 PM, Jon Goodman jon@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
>> 
>> 
>> Thanks. Wouldn't "Bite" be provided by either the gravure screen or aquatint. The gravure screen is a separate exposure, the aquatint is a physical entity. I am not clear how the gravure positive is made differently in those terms. The screening inherent in inkjet film has never seemed to have any noticeable difference from analog film.
>> Jon
>> 
>> Sent from my iPad
>> 
>>> On Sep 3, 2017, at 11:35 AM, 'forums@...' forums@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
>>> 
>>>  
>>> 
>>>>> "BITE" acronyms for?
>>> 
>>> 
>>> Or more specifically the bite is simply referring to the divits and the “bite size” is their width, “bite depth” their depth, etc.  It all gets wrapped under one term I guess is how I see it. I’m no expert at all so others should correct me here if I’m wrong . . .
>>> 
>>> Best,
>>> Walker
>>> 
>>> 
>>>> On Sep 3, 2017, at 9:34 AM, forums@... wrote:
>>>> 
>>>> TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).
>>>> 
>>>> Best and cheers,
>>>> Walker
>>>>> .
>>>>>  
>>>>> 
>>>> 
>>> 
>>> 
>> 
> 
>

Re: The limits of working with QTR

2017-09-03 by skapuskar@...

Sandy, you are very right on this. The DR of the neg needs to be as close as possible to the exposure scale of the process. The closer it is, the less you will have to deal with a crippled correction curve.

A friend of mine asked me to help him out creating a profile for negatives to be printed on silver gelatin paper. To be honest, not my way of printing silver gelatin, I'm an old fashioned guy still preferring printing by hand under my enlarger. Anyway, I took it as a challenge. The advantage of experimenting with digital negs for silver paper is the fact that process parameters can be kept very consistent (same developer, temperature, same light source, I have a cold light enlarger with light probe and compensating timer), and the DR is quite low, around 1,0 D, so ink deposit limit on OHP is easy to control.

My base curve is a straight line array, composed of the most blocking inks for the specific process, obtained with the QTR calibration pattern. Somehow I have been getting better results with this approach than cross-over ink profiles. The difficulty is always getting good separation in the last 20% of the highlights, hence my initial post about problems with self-masking within the carbon process and paper inertia in the case of silver paper. The need of a K or Toner boost seems mandatory for me to obtain a clean white and fair separation between 5-10-15-20% of the highlights. This is what I'm talking about regarding 'smoothness' in my previous post, it is not about ink pattern grain, I'm quite happy with what I obtain so far.

When I mentioned the limits of QTR, it is because it can not take into account the S-curves of silver paper/alt-processes, their initial inertia to exposure, self masking of sensitizer concentration, etc., may others chime in with other process properties :-)
I always end up having to tweak the final result manually.

Grey curve first, then Linearize command, or the other way around?
I have tried both, resulting in two different curves, both worked pretty well.
Preference was grey curve first, then linearization.

I believe it is simply impossible to have a software to create that perfect profile for any alternative process, so manual (human) tweaking is necessary, and I like that idea.

For my carbon work, for example, I do all my calibration with a 2% dichromate solution, creating a grey curve with my densitometer values in QTR - then new test print and linearizing output for the final profile.
In the end, the most pleasing result I get, is printing the same profile with a 1% dichromate solution.

Sidney

Re: [QuadtoneRIP] The limits of working with QTR

2017-09-03 by Alan Vlach

Also, if you only use the mk channel you will not be happy with the highlights. The will be very grainy. It's important not to have any black in the highlight areas. 

Sent from my iPhone
Show quoted textHide quoted text
> On Sep 3, 2017, at 12:23 PM, 'forums@...' forums@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> Make a “noisy” negative using a specific dither. Or print directly onto a polymer plate with 1 channel using a slightly different dither.
> 
> One way to do this is the print directly onto the plate with Matte black ink using the Epson (or QTR) driver and only 1 channel of ink. This creates the proper amount of pure dots. We are working on something that will be a bit more ideal for that but it is competing with lots of other things on our plates (sorry for the pun).
> 
> I’m sure Don Messick could elaborate if he was on this list.
> 
> Best,
> Walker
> 
> 
>> On Sep 3, 2017, at 12:16 PM, Jon Goodman jon@jgoodgravure.com [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
>> 
>> 
>> Thanks. Wouldn't "Bite" be provided by either the gravure screen or aquatint. The gravure screen is a separate exposure, the aquatint is a physical entity. I am not clear how the gravure positive is made differently in those terms. The screening inherent in inkjet film has never seemed to have any noticeable difference from analog film.
>> Jon
>> 
>> Sent from my iPad
>> 
>>> On Sep 3, 2017, at 11:35 AM, 'forums@...' forums@walkerblackwell.com [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
>>> 
>>>  
>>> 
>>>>> "BITE" acronyms for?
>>> 
>>> 
>>> Or more specifically the bite is simply referring to the divits and the “bite size” is their width, “bite depth” their depth, etc.  It all gets wrapped under one term I guess is how I see it. I’m no expert at all so others should correct me here if I’m wrong . . .
>>> 
>>> Best,
>>> Walker
>>> 
>>> 
>>>> On Sep 3, 2017, at 9:34 AM, forums@walkerblackwell.com wrote:
>>>> 
>>>> TIL means total ink limit (how much actual ink goes down per tone). Bite is how separate and defined the divits are in a gravure plate. Bite is not an issue with other types of printing. In fact, with most processes you are looking for the exact opposite (a very smooth grainless negative).
>>>> 
>>>> Best and cheers,
>>>> Walker
>>>>> .
>>>>>  
>>>>> 
>>>> 
>>> 
>>> 
>> 
> 
>

Re: [QuadtoneRIP] Re: The limits of working with QTR

2017-09-04 by forums@walkerblackwell.com

> On Sep 3, 2017, at 6:37 PM, skapuskar@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> I believe it is simply impossible to have a software to create that perfect profile for any alternative process, so manual (human) tweaking is necessary, and I like that idea. 


We’ve done it with PiezoDN+QTR for all continuous tone processes. It requires a measuring device (spectrophotometer) but zero manual curve adjustments or Photoshop tweaks to the image. It does require non-standard ink-set. But if manual is the way you want it, there is no foul in that . . . .

Best,
Walker

Re: [QuadtoneRIP] Re: The limits of working with QTR

2017-09-04 by sanking@...

Carbon among alternative printing processes is especially challenging for a number of reasons, not least of which is the fact that, strictly speaking, it is impossible to print paper white and close highest highlights with continuous tone negatives. A carbon relief is made up of a hardened film of gelatin + pigment. At 0% there can be no film or pigment, as the mechanical nature of the process causes the film to break off at some point before you get to pure paper white.

That does not mean it is impossible to make good prints with carbon transfer, because maximum white is a subjective quality and in most cases absolute paper white is not desirable nor necessary. It does mean, however, that there is very little leeway in contrast for optimum image quality. Too much contrast in the negative or the process and the highlights will begin breaking away somewhere between 5%-10% and 0%. Too little contrast, and the highlights will look dull.

And as Sidney as suggested, this is not a QTR issue, but a process issue. It is possible that this problem could be addressed in QTR with a negative that is continuous tone in the shadows and mid-tones, but increasingly dot in nature in the highlights. But that, if possible, would require a fairly complicated profile.

Sandy

Re: [QuadtoneRIP] Re: The limits of working with QTR

2017-09-04 by Walker Blackwell

I have a preliminary prototype for this that goes to double channel mix of Pk-Mk with Piezo "p2" ink setup and then to just Mk at the very end using different type of dither than in qtr but it will take time to get the other stuff set to test. Basically the last 13% go from contone to pk/mk to mk.

A few on the PiezoDN list have mentioned this is a need so it';s been on the R&D log for me for a bit. We'll see . . .

Best,
Walker
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On Mon, Sep 4, 2017 at 4:29 PM sanking@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

Carbon among alternative printing processes is especially challenging for a number of reasons, not least of which is the fact that, strictly speaking, it is impossible to print paper white and close highest highlights with continuous tone negatives. A carbon relief is made up of a hardened film of gelatin + pigment. At 0% there can be no film or pigment, as the mechanical nature of the process causes the film to break off at some point before you get to pure paper white.

That does not mean it is impossible to make good prints with carbon transfer, because maximum white is a subjective quality and in most cases absolute paper white is not desirable nor necessary. It does mean, however, that there is very little leeway in contrast for optimum image quality. Too much contrast in the negative or the process and the highlights will begin breaking away somewhere between 5%-10% and 0%. Too little contrast, and the highlights will look dull.

And as Sidney as suggested, this is not a QTR issue, but a process issue. It is possible that this problem could be addressed in QTR with a negative that is continuous tone in the shadows and mid-tones, but increasingly dot in nature in the highlights. But that, if possible, would require a fairly complicated profile.

Sandy

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