Fundamental question about the relevance of exposure scale with digital negatives

While I've been printing with various alternative processes for a number of years and have read many books, reading through my just received copy of Don Nelson's (fantastic) book on Kallitype, VDB and Argyrotype brought up a question that I hadn't previously considered.
The book is very well illustrated and contains a lot of comparisons regarding paper and toners and how they play with the different processes. One of the attributes that's always listed, is exposure scale (ES) for both, toners as well as papers.

Since I often print kallitypes (which I develop with sodium citrate), I looked closely at the table listing dmax and ES for the different toners. I'm mostly printing on Hahnemühle Platinum Rag (HPR). In Don's book, the dmax on HPR for kallitypes developed with sodium citrate is 1.42 and (for example) borax is a much lower 1.33. However, the ES behaves the exact opposite: 1.9 for sodium citrate and 2.7 for borax. That initially confused me.

From my (admittedly limited) understanding, ES is defined as how many steps a given process can reproduce on (for example) a Stouffer stepwedge between paper white and pure dmax. So, in essence, it is a measure of contrast - high ES representing a low contrast and low ES representing a very contrasty print.

Here comes my question: with analog negatives, ES seems a very important piece of information for the process, since the negative has to be exposed and developed to cater to the limitations of the process. But with digital negatives, is ES really an important factor? If we do a proper linearisation, we do compensate for the shortcomings of the process, don't we? If we have a process with a long ES (say, salt printing), then we print a negative with very dense highlights and the curve takes care of the rest, making sure the tones between dmax an paper white land in the right spot. Now, I can see that it might be easier to linearise for a process with a long ES (if you can print a dense enough negative) since the density variations on the negative between tones are greater, but in theory, it should be possible to linearise both perfectly: processes with small and large ES. And only dmax really counts to expand the 'scale' of a print.

However, my understanding of this might be completely wrong. If so, please forgive my ignorance. I would like to hear some insights into this from people way more experienced than me. In the past, I've just glossed over the mentioning of ES, but re-reading some of the books in my bookshelf (and Christina Anderson's fantastic new paper chart on alternativephotography.com), the term seems to be omnipresent. But does it only really matter for analog negatives, or does it equally apply to digital negatives?

Thanks for any insights,
Jo

maverickaesthetics said:

However, my understanding of this might be completely wrong.

Click to expand...

Quite the opposite - it's entirely correct!

maverickaesthetics said:

But does it only really matter for analog negatives, or does it equally apply to digital negatives?

Click to expand...

To clarify, the exposure scale of the process applies to the process, regardless of the negative used. But within the stipulations you also provided yourself: that in a workflow with digital negatives, you'll adjust the negative for this by digital means. In silver gelatin, you indeed expose, develop and perhaps reprocess the negative to suit the purpose. The net result is comparable however: a negative with a density range that matches the requirements of the printing process.

I have been asking this myself recently but haven't found a definitive answer yet as I just sticked to the time-tested methods of the fully analog workflow which worked for me. But it was years ago that I stopped printing and switched to digitizing my negatives with a digital sensor in a camera which has a much broader dynamic range working with raw-data than photographic paper.

In theory I should adjust the gamma of my development to this broader range to get better differentiation of the fine differences within the grey-scale. But at the same time one should not exceed the optimum of the films dynamic range and avoid unwanted side-effects on sharpness and grain.

Does anyone know a definitive source about the topic of optimizing negatives for the hybrid-workflow?

skahde said:

Does anyone know a definitive source about the topic of optimizing negatives for the hybrid-workflow?

Click to expand...

Your question is the opposite of what @maverickaesthetics is asking. Maybe it's better to make a separate thread for it.
This thread is about how to produce negatives to fit the requirements of an analog, 'alternative' printing process.
Your question is about how to make silver-gelatin negatives optimally suited for digitizing with a camera. That's a different issue.

koraks said:

Quite the opposite - it's entirely correct!


To clarify, the exposure scale of the process applies to the process, regardless of the negative used. But within the stipulations you also provided yourself: that in a workflow with digital negatives, you'll adjust the negative for this by digital means. In silver gelatin, you indeed expose, develop and perhaps reprocess the negative to suit the purpose. The net result is comparable however: a negative with a density range that matches the requirements of the printing process.

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Thanks for your reply, Koraks. That helps clarifying this in my mind.

However, if I transfer this knowledge to cyanotype (probably the process I'm most experienced in), and compare development with plain water (very contrasty) with acidified water development (much more detail in the midtones, as well as slight increase in dmax), then I'm getting confused. I now only develop with acidified water, but when I started, I did not. But I don't remember - and my memory might be wrong - having as full a range of tones back then, despite having a very good linearisation at the time.

As a follow-on question then: with digital negatives, is there then any advantage of a process having a long tonal scale when, in theory, we can bring all tones in line through linearisation? For processes with a shorter ES, we would also need less ink density on our negatives. However, I wonder if we're running into physical limitations of a printer's 'resolution' in term of ink density...

maverickaesthetics said:

But I don't remember

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Memory is tricky. Repeat the experiment with what you know now.
Coincidentally, I did some mucking about with New Cyanotype some time ago and bumped into this issue as well: https://www.photrio.com/forum/threa...surprisingly-short-curve-high-contrast.206252
The TL;DR is that using a strong acid (HCl) expanded the ES (in your wording) of the process.

maverickaesthetics said:

with digital negatives, is there then any advantage of a process having a long tonal scale when, in theory, we can bring all tones in line through linearisation?

Click to expand...

No, not really, although I follow this comment, too:

maverickaesthetics said:

I wonder if we're running into physical limitations of a printer's 'resolution' in term of ink density...

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that's indeed a concern. The density that an inkjet printer lays down is essentially fixed. Reducing the tonal scale means you're effectively only using part of the tonal scale it can print. There are a couple of ways to do this, but they ultimately tend to boil down to somewhat coarser tonality. However, the net result may be perfectly acceptable nonetheless.

My take on alt. processes is that in most cases, there's often a set of parameters that will generally result in an optimal print quality (dmax, rendering of nuances, etc.) and that this involves a certain limitation on the tonal scale of the negative. In other words: you need a negative of that (more or less exact) tonal scale to make the best possible print. As such, the tonal scale of the negative is prescribed in a way by the process.

I'm aware of the opposite, i.e. tailoring the printing process by altering process parameters to the negative. However, in my experience, this nearly always results in a slightly (or distinctly) inferior print. So in practice, I've always felt it's best to first figure out how to best perform the printing process, and then make the negatives that are required for it - not the other way around.

Seems like we're thinking along similar lines there, Koraks. If our process gives us a longer ES (within the density range achievable by our printer), we might give the printer more control over getting the density steps correct.

Re tailoring the printing process to fit the negative: since I'm currently printing 99% digital negatives, I never felt the need to alter the process (well, with the exception of using a small amount of dichromate in my kallitype developer to clear the highlights), since I just adjust the digital negative.

koraks said:

Coincidentally, I did some mucking about with New Cyanotype some time ago and bumped into this issue as well: https://www.photrio.com/forum/threa...surprisingly-short-curve-high-contrast.206252
The TL;DR is that using a strong acid (HCl) expanded the ES (in your wording) of the process.

Click to expand...

Just looked at your post regarding cyanotype. I mostly print with the classic cyanotype formula since it works better for my multi-colour cyanotype work. But I have one project that I use Mike Ware's New Cyanotype formula for. The process is VERY paper-picky. If you have access to Hahnemühle Platinum Rag, give that a try since it works very well. And you definitely need to use a strong acid for development. I'm using 1% sulfamic acid for development (which should behave similar to HCL, I'd imagine, but is a bit less of a hassle to handle). I print this project on Fabriano Artistico, which is a heavily buffered paper; but I really like the texture, so I remove the buffer with a sulfamic acid bath before sensitising.
The dmax is fantastic.

Anyhow, thanks very much for the replies, I am feeling now a lot more confident that I'm not missing a huge part of the puzzle of alt printing

maverickaesthetics said:

my multi-colour cyanotype work

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I'd love to see that!

Years ago I did a lot of cyanotype, initially Classic and after a while I moved to New. I used different papers back then than the paper I used on that recent test, so I suspect that this may have played a role, indeed. My memory is also hazy on my processing back then (hence my earlier comment!); I may or may not have been using something like HCl back then for the first wash.

maverickaesthetics said:

If you have access to Hahnemühle Platinum Rag

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Theoretically, yes, but so far I've never ran into a situation where the "official" alt. papers were a hard requirement. I'm currently mostly printing carbon transfer and sometimes a little salted paper or Van Dyke. Those work OK on the papers I'm using currently (Schut Laurier and Schut Salland); especially carbon "doesn't care" what you use in terms of paper as long as it survives being wet. At least the former paper (Laurier) also works very well with New Cyanotype provided an acid wash is used for the first bath. No buffer-stripping required. Dmax is excellent, tonal scale is very nice as well. I might one day try the Platinum Rag, but I admit that I've always taken some pleasure out of plundering the paper section of my local carts & crafts store and then making some of the papers there work for my purposes.

I must have some sulfamic acid somewhere and might give that a go for the New Cyanotype at some point. I frequently use HCl also for other purposes and never found it particularly wayward to work with. I use the hardware store 10% concentration that's common around here. It's not particularly nasty, apart from the fact that it will make anything with a hint of iron in it rust.

koraks said:

Your question is the opposite of what @maverickaesthetics is asking. Maybe it's better to make a separate thread for it.
This thread is about how to produce negatives to fit the requirements of an analog, 'alternative' printing process.
Your question is about how to make silver-gelatin negatives optimally suited for digitizing with a camera. That's a different issue.

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My apologies, I should have read more carefull and put away my soapbox for another day.

koraks said:

I frequently use HCl also for other purposes and never found it particularly wayward to work with. I use the hardware store 10% concentration that's common around here. It's not particularly nasty, apart from the fact that it will make anything with a hint of iron in it rust.

Click to expand...

That's exactly the reason why I'm using sulfamic acid ;-)

Here are a couple of multi-colour cyanotypes (only cyanotype chemistry is being used, but for tri-colour images, the magenta layer is toned with, in my case, madder root):

This is a duotone print:


And this is a tri-colour cyanotype:

That's absolutely fantastic, @maverickaesthetics ! I take it you do the madder-toned layer first? Absolutely fantastic work!

@skahde no worries; just wanted to point this out before we have two trains of thought crossing all the time; it tends to result in confusion sooner or later. Please feel free to bring up your question in a separate thread!

koraks said:

I take it you do the madder-toned layer first?

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Thanks, Koraks. Yes, you have to print the magenta layer first. Bleach the cyan layer (printed with the magenta/green negative) and tone with madder root. Then print the yellow layer (blue negative) with cyanotype and bleach back to yellow. Finally, print your cyan (red negative) layer as a regular cyanotype. Madder roots stains the paper quite badly, which reduces the overall contrast - which is probably my biggest issue with this process.

I might start a new thread with some images and notes if there's interest...

In the meantime, I have written a long-ish article about the process at https://www.alternativephotography.com/multi-coloured-cyanotype-print/. It's based on the work of Annette Golaz, whom we have to thank for the modernisation (and sophistication) of the whole toning cyanotype process. I've tried most of the published methods that came before her book and they were marginally acceptable at best. In no way could they have been used for anything resembling a full-colour print. But with Annette's experiments, we can now actually do fairly convincing full-colour cyanotypes...

Beautiful work!

To the extent you have full control over the curve of the digital negative, any original can be made to work with any print process.

But you don’t want to start with a bad (underexposed, underdeveloped) negative. You still want to have a negative that you make following the principles of subject luminance range, exposure and development.

The closer you are to already matching the print process the less you will have to change the curve.

maverickaesthetics said:

While I've been printing with various alternative processes for a number of years and have read many books, reading through my just received copy of Don Nelson's (fantastic) book on Kallitype, VDB and Argyrotype brought up a question that I hadn't previously considered.
The book is very well illustrated and contains a lot of comparisons regarding paper and toners and how they play with the different processes. One of the attributes that's always listed, is exposure scale (ES) for both, toners as well as papers.

Since I often print kallitypes (which I develop with sodium citrate), I looked closely at the table listing dmax and ES for the different toners. I'm mostly printing on Hahnemühle Platinum Rag (HPR). In Don's book, the dmax on HPR for kallitypes developed with sodium citrate is 1.42 and (for example) borax is a much lower 1.33. However, the ES behaves the exact opposite: 1.9 for sodium citrate and 2.7 for borax. That initially confused me.

From my (admittedly limited) understanding, ES is defined as how many steps a given process can reproduce on (for example) a Stouffer stepwedge between paper white and pure dmax. So, in essence, it is a measure of contrast - high ES representing a low contrast and low ES representing a very contrasty print.

Here comes my question: with analog negatives, ES seems a very important piece of information for the process, since the negative has to be exposed and developed to cater to the limitations of the process. But with digital negatives, is ES really an important factor? If we do a proper linearisation, we do compensate for the shortcomings of the process, don't we? If we have a process with a long ES (say, salt printing), then we print a negative with very dense highlights and the curve takes care of the rest, making sure the tones between dmax an paper white land in the right spot. Now, I can see that it might be easier to linearise for a process with a long ES (if you can print a dense enough negative) since the density variations on the negative between tones are greater, but in theory, it should be possible to linearise both perfectly: processes with small and large ES. And only dmax really counts to expand the 'scale' of a print.

However, my understanding of this might be completely wrong. If so, please forgive my ignorance. I would like to hear some insights into this from people way more experienced than me. In the past, I've just glossed over the mentioning of ES, but re-reading some of the books in my bookshelf (and Christina Anderson's fantastic new paper chart on alternativephotography.com), the term seems to be omnipresent. But does it only really matter for analog negatives, or does it equally apply to digital negatives?

Thanks for any insights,
Jo

Click to expand...

This is a fantastic question one worthy of every alt printer of considering.

Back in the 80's and 90's before digital I had to prepare all my negatives with process and development and hopefully the original scene was such that I received a good negative, then I would need to test each individual negative for each process that I was currently working with, (in my case - silver and Pt Pd)
If one was not careful it would become a very laborious process to make a incredible print . So there was the idea to make a longer scale neg for PT PD than lets say Silver and this required a different development time structure.
I have prints from those original camera negs and will say they contacted out beautifully.

Now fast forward to current times, I use digital negatives and PS and in any given working session I can be assured that the prints I make will be beautiful and every bit as pleasing than two decades ago.
We use quad tone rip and Boutwell's system to calibrate, before than I had Ron Reeder to calibrate, and as well I did own a Lambda RGB laser machine where we calibrated silver film for contact process.

One thing I have learned is that we adjust the process to match the negatives these days rather than the other way around, so we have figured out our
process times , methods that work well with each coating we are trying to develop.
This will mean we use the same negative for all process, silver, gum, cyanotype and pt pd. We calibrate using Palladium prints the step wedge
and this the only profile we use to make our digital negatives.
The goal of a profile is to have the 100 input Lab tones of the original file match as closely as the 100 Lab tones of the final print . Once this established and it rarely takes more than two attempts with Boutwell's or Reeder's system. The same was for the Lambda unit where we calibrated a 21 step wedge by adjusting the RGB laser strength to create Lab numbers that coincided with input.
The systems I am mentioning require a spectrometer or an inboard sensitometer that can read transmission light.

Now you have a profile curve made for the receiving material (Pictorico) that is always consistent and will give you good negatives
at all times if you are accurate yourself.

Because silver is able to be adjusted quite easily with split filter exposures we can tame the curve a bit by lowering the original contrast of the file and
simply make adjustments when printing silver. Each different scene from 10 different photographers can be laid down on the paper and they will be super close and this is what is making the alt process now more affordable with less paper waste and for the printer less water and time to make a living.

Gum Bichromate (which I do quite a lot with) works well with the same negatives and we have adjusted our. process procedures that do not look anything like what one would read in some of the fantastic books out there on Gum Printing.

And since we calibrated using the longer scale PT PD process we are assured great test strip and final print every time and it also saves time on wasted paper and time.

Today we have a lot more control on what the final printing negative looks like and this look can be adjusted early in the workflow.
If it looks like a duck (neg), if it walks like a duck(neg) and it quacks like a duck(neg) then it probably is.

Not sure if this helps the OP but certainly something to consider .

Carnie Bob said:

One thing I have learned is that we adjust the process to match the negatives these days rather than the other way around, so we have figured out our
process times , methods that work well with each coating we are trying to develop.
This will mean we use the same negative for all process, silver, gum, cyanotype and pt pd. We calibrate using Palladium prints the step wedge
and this the only profile we use to make our digital negatives.

Click to expand...

Bob, I think I read that before (or maybe gleaned it from one of your YT videos). And I think you might be one of the few to actually work like this.
Maybe I'm misunderstanding something here, but I feel that is disregarding one of the benefits of digital negatives: to cater them to your process (and not the other way round). I use the same tools you mention (QTR, Richard Boutwell's program and a spectrophotometer) and it's easy enough to create a curve (or required density) for each process. The required density for gum and pt/pd is quite different, so I'd much rather not lay down as much ink for gum if I don't have to.
The only processes I struggle to get a good calibration on are pigment processes (gum bichromate and PrintMaker's Friend in my case). And that's mostly related to me failing to be consistent enough in my coating. It's ok, but not as precise as I would like it to be. I really appreciate your experience with gum (and some of your old videos were one of my inspirations to get into the process). How did you adjust your gum processes to use the dense pt/pd negatives? Through contrast control via proportion of bichromate? Also, any tips on consistent coating would be greatly appreciated ;-)

As a side-note: Bob, I have the second print from above (the one with the door) as a gum bichromate version in the same gum exhibition as you next week. I never thought this possible even a few months ago...

maverickaesthetics said:

Bob, I think I read that before (or maybe gleaned it from one of your YT videos). And I think you might be one of the few to actually work like this.
Maybe I'm misunderstanding something here, but I feel that is disregarding one of the benefits of digital negatives: to cater them to your process (and not the other way round). I use the same tools you mention (QTR, Richard Boutwell's program and a spectrophotometer) and it's easy enough to create a curve (or required density) for each process. The required density for gum and pt/pd is quite different, so I'd much rather not lay down as much ink for gum if I don't have to.
The only processes I struggle to get a good calibration on are pigment processes (gum bichromate and PrintMaker's Friend in my case). And that's mostly related to me failing to be consistent enough in my coating. It's ok, but not as precise as I would like it to be. I really appreciate your experience with gum (and some of your old videos were one of my inspirations to get into the process). How did you adjust your gum processes to use the dense pt/pd negatives? Through contrast control via proportion of bichromate? Also, any tips on consistent coating would be greatly appreciated ;-)

As a side-note: Bob, I have the second print from above (the one with the door) as a gum bichromate version in the same gum exhibition as you next week. I never thought this possible even a few months ago...

Click to expand...

Ok I see your point, maybe I can suggest that with gum all bets are off, it is not a photographic process but rather a gum hardening process. I use a very warm water with agitation bath, I feel Calvin uses the same for his carbons, and in my space the gum process is done within three minutes maybe 4 if my first bath is not warm enough, I apply water to the back of the print and then to the front of the print within the first 20 seconds and in my world the same profile is used for gum as pt pd , cyanotype or silver.
With gum its very simple, the AD hardens the gum with exposure and the warm water washes off the unwanted. Not to be copntreversial here but it really is that simple, I play no mileage in complicating the process.

If we use the same profile for , all processes and sell these prints as exhibition quality I think we are in a good place, My videos on gum are DATED and may or not be relevant , for example I use a very expensive Cone Edition exposing unit that has significantly improved our work, I use Calvins pigments for now for colour gum CMY and I use a modified BW conversion and NOT THE USELESS K .
The K is the layer or negative that if most people understood what its actual purpose was would not be using it.

Regarding contrast or colour control of the gum bichromate, look at your image, if it is very complicated with a lot of various elements then a full pigment load , AD load , and Gum load is needed.
If the image has a lot of open area of colour then two lighter coatings with a lower percentage of pigment is needed.

I will say this , what is good in my space will be different in your space so what I say may not be totally relevant to your experience.

I think one thing that is very important to understand, excuse me for being silly here. I am a big fan of Karate Kid teachings

Silver and Palladium and inkjet is a wash on process
Gum Bichromate and Cibachrome is a wash off process

If you can see this then you know where I am coming from.

Bob

maverickaesthetics said:

Bob, I think I read that before (or maybe gleaned it from one of your YT videos). And I think you might be one of the few to actually work like this.
Maybe I'm misunderstanding something here, but I feel that is disregarding one of the benefits of digital negatives: to cater them to your process (and not the other way round). I use the same tools you mention (QTR, Richard Boutwell's program and a spectrophotometer) and it's easy enough to create a curve (or required density) for each process. The required density for gum and pt/pd is quite different, so I'd much rather not lay down as much ink for gum if I don't have to.
The only processes I struggle to get a good calibration on are pigment processes (gum bichromate and PrintMaker's Friend in my case). And that's mostly related to me failing to be consistent enough in my coating. It's ok, but not as precise as I would like it to be. I really appreciate your experience with gum (and some of your old videos were one of my inspirations to get into the process). How did you adjust your gum processes to use the dense pt/pd negatives? Through contrast control via proportion of bichromate? Also, any tips on consistent coating would be greatly appreciated ;-)

As a side-note: Bob, I have the second print from above (the one with the door) as a gum bichromate version in the same gum exhibition as you next week. I never thought this possible even a few months ago...

Click to expand...

Catering you negative to the process is the easy part and most of us go through this stage, now try to cater your process to linearized negatives.

Also, any tips on consistent coating would be greatly appreciated ;-)

As a side-note: Bob, I have the second print from above (the one with the door) as a gum bichromate version in the same gum exhibition as you next week. I never thought this possible even a few months ago...



Ok on coating very simple... We use two brushes, the exact same one Richelson(sp)
One is for Pt Pd and one which is now 25 years old for gum, - We take very good care of our brushes
IMHO the secret of coating is Gliding and the word Brushing should get out of your head... you are not pushing the liquids onto the paper but rather
gently gliding and letting them sink into the papers water base level. at around 55% .

We are very gentle with our coatings and with the fine edge of the Richleosn (sp). we will gently apply to the whole paper surface once then with maybe
three strokes across without the edge of the brush curving apply the liquid , that is it. so absolutely do not brush rather than glide, I you ever have handled
a newborn consider this when putting anything on paper.
I have seen people do the opposite and drive the liquid into the paper - result grainy ugly prints.

Hey good luck with the show I hope we both sell our prints

Bob

Thanks for the clarifications, Bob. I'll have a go with the warm water. I forgot that you're doing this...

Carnie Bob said:

The K is the layer or negative that if most people understood what its actual purpose was would not be using it.

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Actually, this is quite right. And I like your idea of specifically creating a targeted black layer. But looking at Calvin's prints, for example, and knowing that he prints 'proper' CMYK prints, I wonder if it just has to do with the profile to create the separations. I can't imagine that if you do a specific colour profile for a process, that the k layer is indeed useless. I think you are correct if you're using one of the standard CMYK profiles (that were created for the commercial printing industry and take into consideration limits of the printing processes that industry uses), but if you have a profile for your process, that should produce a meaningful black channel.

maverickaesthetics said:

But looking at Calvin's prints, for example, and knowing that he prints 'proper' CMYK prints, I wonder if it just has to do with the profile to create the separations.

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Have you read his Gum Printing manual? He's very specific in it on how he works. It's fundamentally different from Bob's approach in several ways. I'm not saying either is better than the other. It's a different approach and a different philosophy for the most part, and that culminates in differences in technical execution. I've observed both Calvin and Bob for a couple of years now, from a distance of course, and to me it's clear they're coming from totally different angles. This is what makes it interesting and also why I'm so happy Bob shares his insights here.

Profiling plays a big role in Calvin's work, but you have to start by asking with what expectations and beliefs he goes into the profiling exercise vs. how Bob approaches it. I think if you were to compare those thoughts, they'd turn out to be very different indeed.

Minds work in a different way. In this case, you see it in the prints. I think that's immensely valuable and one of the reasons why 'artisanal' printing will stick around, forever.

koraks said:

Have you read his Gum Printing manual?

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I have read Calvin's gum printing manual and the calibration one. And I've been on his two-week colour Printmakers Friend workshop a year ago.
He's got a very scientific approach (I work in science, so this isn't too strange for me) and he's very good at what he does. After the first week of the workshop (in which we had covered bw printing and A LOT of theory), he said: ok, now we start with the theory...

I'm personally sitting somewhere between Bob and Calvin, I think. I'm possibly a bit OCD with calibrations (I just love when they fall within less than 2% of the ideal line), but I also embrace the wabi sabi of alt processes. I love to learn from both approaches, since they give you a broader tool set.

We had a discussion amongst the workshop participants (who, if they had prior experience with gum printing, which not everyone did, were much closer to the more intuitive, 'the process dictates where we're heading' school than to Calvin's analytical approach) about the use of colour. Calvin markets his Printmaker's Friend in the three basic colours magenta, yellow and cyan. Some participants wanted to use what they were used to, like perylene maroon for example. However, the pigments that Calvin chose allow for the maximum gamut possible (within reason), so they can normally mix exactly the colour that this shade of maroon would also create (because that has a much smaller gamut and lies within the gamut of Calvin's pigments). But it became clear that part of most people's workflow was to create a 'neutral' (colour-wise) digital image and then develop the 'tone' or mood of it by using a specific mix of pigments in printing. The same thing, however, can easily be done if you create the image (how you want it to look in the print) on the computer and then use a good profile with your basic pure colours to mix your favourite palette. It's a fundamentally different approach, one is created BEFORE printing, one is created DURING printing. But the result can be the same.

But I don't want to highjack my own thread. This is now going quite far off the original topic. But very interesting discussions. Thanks a lot everybody.

Calvin and I are friends, indeed I helped proof read his gum manual. Our approaches are much different that is true, the main difference is IMO that Calvin
is dedicated to stochastic separation negatives so as to retain highlight detail when washing out with hot water, as I am using inkjet negatives and using warm water.
I absolutely hate the stochastic look and it is very obvious on small prints where one is very close to the print, but falls away due to viewing distance tricks.
From my perspective he is one best carbon printers I have ever met, there are quite a few but I would say under 10 people.
I was going down the colour carbon route for many years, but about 7 years ago did a complete about face and switched to Gum for many personal and professional reasons.

I am using Calvins pigments , but not his black, Basically he walked me through the mixing steps of his pigments and I use his method today, I use warm water and a first washout process much like him, Calvin likes to build up an image with many layers and light progressive coatings whereas I tend to coat thick and adjust my pigment load only when I have large areas of flat colour that are hard to keep on the paper with a thick coating.

We have talked over the years and I appreciate his dedication and skills. I must say I have a very good long term friend ( we logged together in 1969/70 who is IMO the absolute best colour carbon printer in Canada and his buddy Todd Gangler only matches his skills ( they worked together on this process for years with some association with Charles Bergger.)
John does a three transfer onto very , very thick watercolour paper and since he only does big prints one cannot see the stochastic grain. His work is magnifcant and he is really an unknown master photographer/printer.

Each person grows with their process, I kind of cringe when people say the see my videos as most of what I did 6 years ago I do not do today and am always
looking for ways to improve.

I am a professional printer and my day job is making prints of all process that people hang on walls, I work fast and furious and never gaze at my navel wondering what to do next, I think this has allowed me to be successful but I must say that if I was in it for the money this is the wrong job for me as I only give out work that I would be personally satisfied myself, I was part owner of a somewhat successful large printing lab not 10 years ago, I resigned my % of shares because though we were making money I was very unhappy with the product we were producing.
I have no advice on Carbon Printing as there are many that are 10 times better than I , I do have a lot of experience with Gum and am continuing my research, mostly into securing a line of pigments that I crush and produce here in Canada, it is hard for me to rely on others for this one component in the process.

Regarding the K layer that I do not like.... This layer is a combination of C, M , Y and is used in the printing process (offset) so the magazines can use more black ink
than the more expensive C , M , Y.

So with this in mind it is not a true representative of the black or detail element in any image, but rather a compromise.
The definition of UCR - under colour removal and GCR - grey component removal is beyond my scope to explain here, but it is important to understand when you convert to CMY K these elements are going on, you can turn them off and I have and the resulting CMY negatives are much bolder and clear than those separations with UCR and GCR active.

In fact one could argue that going to RGB will in effect give you better negatives.
I have gone down this wormhole and will make my assistant experiment with this aspect of separations.

I have personally found my approach to doing a black and white conversion , and within this conversion lighten all the image key colours so that when I print the Palladium or silver layer, the prints has a much lighter tonal area in the key colours and they come in more intense, - Along with getting rid of the GCR and the UCR when doing the CMY conversion I find a much cleaner and detailed response and the reason I love gum over palladium.

But I am nitpicking here as the difference in all methods of separation basically get me a print which I do like, I must reiterate I have never used the K so I am speaking only from my vantage point.

And I too apologize if I have taken the thread off topic,, OOPss

Carnie Bob said:

The definition of UCR - under colour removal and GCR - grey component removal is beyond my scope to explain here

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Yeah; understandable. Coincidentally this is one of the few remaining areas where I feel GIMP is still lacking as it offers no control over this, or in fact doesn't even make explicit how K is computed in the first place. But that's a whole different tangent altogether.

Carnie Bob said:

And I too apologize if I have taken the thread off topic,, OOPss

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Nope, keep it coming; very welcome as far as I'm concerned and I'm having a feeling @maverickaesthetics doesn't mind either.

maverickaesthetics said:

He's got a very scientific approach (I work in science, so this isn't too strange for me)

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Yeah, I can relate. I've only read his manuals but have not attended his workshop, so you know him better than I do. But what you say rings true in how I know/what I know about Calvin.

maverickaesthetics said:

It's a fundamentally different approach, one is created BEFORE printing, one is created DURING printing. But the result can be the same.

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Yes, indeed, although you should also ask the question IMO if one should try to replicate results in this way. I don't think anyone does that; indeed, one approach fits one printer's 'temperament' and the other fits another perspective. You must have seen/heard of Katayoun's work on the Yevonde prints as well, recently; your story of pigments reminds me of this project.