Separation Negatives for multiple Colour Work

Hi Folks

My new darkroom will be complete in a month, and I am preparing to dip my feet into tri colour gum or carbon. I would like to include a K mask for detail and contrast control.

I would like to hear some responses from those who are currently making separation negatives from colour files for printing colour on carbon or gum.

My first question would be this, as with making negs for offset printing one needs to have the cyan, magenta and yellow screen angles different. I have a Lambda output device and I have ortho BW film in rolls to make large negs.
This device is basically a con tone rgb laser printer and I believe it will work, but do I have to * askew* each separation so that when registered and printed on top of each other the colour image will work. If so can I do this in PS before the separate files are printed?
I understand some here use an image setter which I have offsite availability too as well but if I can do it on my Lambda then its an all in house operation which makes me feel all warm and fuzzy.

Second Question

I plan to mount my printing substrates to aluminum plates , to avoid shrinkage, and in the past I used a strosser punch system , and I wonder if anyone here knows where I can purchase a used one. I plan to work 30x40 inch and under and I do have a Nuark Flip top but need a good punch system.

for now these are my first questions, I am sure more to come,btw I have had time well spent with Sandy and he has been extremely helpful and will be an ongoing inspiration to me.

I have no intentions of making inkjet negatives as I pefer to work with film and that is where I find my comfort level. * I have seen beautiful results with inkjet negs, so no disrespect intended to those who do so *

Hi Bob,
The answer to your first question is no, you don't need to make the negatives as halftone screens, and therefore by extension, you don't need to worry about the angle of the screen. Just print a regular contone negative for each of the separations and it should work fine. Good luck,
Katharine

Thanks Katharine
In a past life I was making separations for advertising purposes and this was the case. I was hoping it was not a requirement.

Katharine Thayer said:

Hi Bob,
The answer to your first question is no, you don't need to make the negatives as halftone screens, and therefore by extension, you don't need to worry about the angle of the screen. Just print a regular contone negative for each of the separations and it should work fine. Good luck,
Katharine

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Yes, for offset color printing a halftone screen is required, but tricolor gum or carbon is nothing like offset printing. It's been my observation that people coming from a color offset printing background to gum printing tend to be handicapped by preconceptions that hinder them rather than helping them in the process of understanding and mastering tricolor gum; understanding from the beginning that they're completely different entities with different mechanisms and different requirements will speed your progress. Good luck.

Give up now bob and save yourself the humiliation.

bob carnie said:

I have no intentions of making inkjet negatives as I pefer to work with film and that is where I find my comfort level. * I have seen beautiful results with inkjet negs, so no disrespect intended to those who do so *

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Bob,

I think negatives from the Lambda on real film should work fine for you.

Honestly, making high quality color gum prints is a lot easier than most people think. Gum is a process that, like any other photographic process, offers a great deal of control. See Keith Taylor's work, for example. Before Keith there would have been people who claimed this kind of control was not possible.

Between color carbon and color gum I would think your chances of satisfaction would be greater with color gum, in large measure because accurate color is less of a requirement with a process like gum, which favors artistic interpretation, than with color carbon, where we expect accurate and naturalistic color.

Sandy

Dear Johnnie Boy

You know me well enough, probably as well as anyone on the internet, we have gone through a lot together, from the days before the first APUG conference, where we both got to meet a lot of wonderful photographers.
I may be slow, but when I put my mind to something it will happen, in fact I can see some of those cross processs negative thingies you do working well with tri colour.* Maybe when you get in Toronto we can start by making some bw separations on the Lambda.

Thanks Katherine, I put the question out specifically because after reading Keith Taylors article in View Camera , the fact he was using a image setter, slightly confused me as I equate that with stocastic or line output which obviously is not the case.* I have talked with photographers from his region that have seen these prints and they describe them as first rate.*
The ability to keep this all in house , is a huge bonus as I now have all the equipment.* Large strosser punch needed*

Sandy you are right after our conversation yesterday I do think I am going to keep carbon for black & white only and use gum for colour work.
Years ago, 1979 or so I saw Stephen Livick's colour gum at a gallery here in Toronto and those small town county fair images have always stuck in my mind.

jd callow said:

Give up now bob and save yourself the humiliation.

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Keith Taylor lurks here I think, so I hope will set me straight if I'm wrong, but in a thread I read here or at APUG or somewhere, I got the impression that his use of the imagesetter was determined by the size of negatives he wanted to make (20x27 in the work he was discussing at the time) but that he uses inkjet negatives for the color separations for smaller gum prints. I've used imagesetter negatives, laser printer negatives, inkjet negatives, and contone film negatives for gum (although never contone film for color separations) and they all work fine for gum in my experience.

I believe that you will do well at either gum or carbon, but I'd recommend choosing one or the other and sticking with it. They each have something of a learning curve to master; if you've already mastered carbon for black and white, why be daunted from using carbon for color just because you've been warned that carbon printers are snobs and "expect natural and realistic color"? The pigments available for use are the same in both cases and therefore the problems of attaining realistic color balance are the same in both cases. In other words, it's no more difficult to achieve realistic color in carbon than in gum, and vice versa.

Not that I wouldn't be delighted to welcome another tricolor gum printer, just sayin' it doesn't make sense to me to learn one process for bw and the other process for color; why learn two processes when you can easily do both monochrome and tricolor with either one?

Katharine
http://www.pacifier.com/~kthayer/

Hi Katharine
There is a colour carbon printer in the city whose work is quite beautiful but I have to say I think the gum's are more in my thinking , I have done ultra stables at Maine workshop over 10 years ago and at the time , the tissues were available with no need to sensitize the tissue before the exposure is made, which I believe is not the case today .
As well I spent some time with Kerik doing some gum over platinum this summer and the potential has my head spinning. I am making silver prints off my lambda and I believe I can make gum over silver prints quite easily in my shop which will open a lot of avenues for me.
Sandys bw carbons are very , very detailed in the shadow areas and I have a long time client who I have been processing and proofing for, whose work would greatly benifit carbon.
These printing methods are basically a personal project with me and I am in no hurry to please clients with my results.
So basically carbon for one paticular person, and gum overs and tri colour gum for me and my friends.

Katharine Thayer said:

Keith Taylor lurks here I think, so I hope will set me straight if I'm wrong, but in a thread I read here or at APUG or somewhere, I got the impression that his use of the imagesetter was determined by the size of negatives he wanted to make (20x27 in the work he was discussing at the time) but that he uses inkjet negatives for the color separations for smaller gum prints. I've used imagesetter negatives, laser printer negatives, inkjet negatives, and contone film negatives for gum (although never contone film for color separations) and they all work fine for gum in my experience.

I believe that you will do well at either gum or carbon, but I'd recommend choosing one or the other and sticking with it. They each have something of a learning curve to master; if you've already mastered carbon for black and white, why be daunted from using carbon for color just because you've been warned that carbon printers are snobs and "expect natural and realistic color"? The pigments available for use are the same in both cases and therefore the problems of attaining realistic color balance are the same in both cases. In other words, it's no more difficult to achieve realistic color in carbon than in gum, and vice versa.

Not that I wouldn't be delighted to welcome another tricolor gum printer, just sayin' it doesn't make sense to me to learn one process for bw and the other process for color; why learn two processes when you can easily do both monochrome and tricolor with either one?

Katharine
http://www.pacifier.com/~kthayer/

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Makes sense to me. You sound like a natural gum printer, and glad to have you aboard.

I was coming back to qualify something I just said; I said that it was no more difficult to attain a correct color balance in carbon than in gum, but that may not be quite accurate. When I said that, I was thinking of of the difficulty of hitting the color balance right in three color printings, which should be essentially the same for either process, but with gum I suspect it's probably easier to adjust the color balance with additional printing(s), if you don't hit it right with the three initial colors. Good luck,
Katharine

Katharine Thayer said:

Makes sense to me. You sound like a natural gum printer, and glad to have you aboard.

I was coming back to qualify something I just said; I said that it was no more difficult to attain a correct color balance in carbon than in gum, but that may not be quite accurate. When I said that, I was thinking of of the difficulty of hitting the color balance right in three color printings, which should be essentially the same for either process, but with gum I suspect it's probably easier to adjust the color balance with additional printing(s), if you don't hit it right with the three initial colors. Good luck,
Katharine

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I have made both color gum and color carbon prints, and your point about the number of printings is exactly correct. With color carbon you get one change to balance the print, whereas with gum it is possible to adjust the color balance with several additional printings. The fact that we work with pre-made cyan, magenta and tissue with color carbon makes this kind of adjustment impossible from a practical point of view.

In any event my experience is that most gum printers are more interested in an artistic rendition that does not always require absolute color fidelity. Color carbon printers are generally after a more purely photographic look where accurate color balance is expected. This is not a value judgement about one method or the other, merely an observation based on my experience.

Sandy King

Thankyou Katharine

so here is a question, which perplexes me after reading the Taylor article.
Why only three colour separations?
Why not a k separation for detail and contrast control?
I see how with mounting to aluminum the shrinkage/registration issue is gone, so why not use a fourth detail exposure?

Bob

Katharine Thayer said:

Makes sense to me. You sound like a natural gum printer, and glad to have you aboard.

I was coming back to qualify something I just said; I said that it was no more difficult to attain a correct color balance in carbon than in gum, but that may not be quite accurate. When I said that, I was thinking of of the difficulty of hitting the color balance right in three color printings, which should be essentially the same for either process, but with gum I suspect it's probably easier to adjust the color balance with additional printing(s), if you don't hit it right with the three initial colors. Good luck,
Katharine

Click to expand...

bob carnie said:

Thankyou Katharine

so here is a question, which perplexes me after reading the Taylor article.
Why only three colour separations?
Why not a k separation for detail and contrast control?
I see how with mounting to aluminum the shrinkage/registration issue is gone, so why not use a fourth detail exposure?

Bob

Click to expand...

Bob,

Some people get the detail and density with a first cyanotype layer.

Sandy

It seems to me I read where the guy who did the Freida Kahlo (Murry?) colour carbon's used a black layer, but then I suspect that is something altogether different than tri-gum.

bob carnie said:

Thankyou Katharine

so here is a question, which perplexes me after reading the Taylor article.
Why only three colour separations?
Why not a k separation for detail and contrast control?
I see how with mounting to aluminum the shrinkage/registration issue is gone, so why not use a fourth detail exposure?

Bob

Click to expand...

With a properly printed tricolor gum print, you get all the detail and contrast you need from the three color printings (do you think Keith's prints, or Livick's tricolor prints, need more detail or contrast than they have?) so why sully the colors with a black printing? Makes no sense to me. I suspect you're still mistakenly thinking this works like offset printing. CMYK profiles for offset printing tend to move most of the density/contrast from the color printers into the black printer; when you use those kinds of separations you *have* to use the black printer to get the contrast. But tricolor separations for gum printing retain the contrast in the color printings so no black printer is required.
katharine

sanking said:

The fact that we work with pre-made cyan, magenta and tissue with color carbon makes this kind of adjustment impossible from a practical point of view.

Sandy King

Click to expand...

Wow, I just learned something; I didn't realize there were premade tissues in cyan, magenta and yellow for tricolor printing. In that case, I would think that it would be much easier to print tricolor carbon than tricolor gum, where we're pretty much on our own with regard to choosing the pigments and the pigment concentrations to achieve a realistic color balance. I personally like the flexibility of choosing my own color palette, but I would think for someone interested in precise color rendition, that carbon with the premade tissues would take a lot of the uncertainty out of the color balance issue.

jd callow said:

It seems to me I read where the guy who did the Freida Kahlo (Murry?) colour carbon's used a black layer, but then I suspect that is something altogether different than tri-gum.

Click to expand...

Traditionally a K layer was not used in making color carbon and color carbro prints when printing from continuous tone negatives, although I understand that a few top printers from the old days did use a K layer for certain types of images.

When the Polaroid color carbon and Ultrastable methods were introduced they were based on printing with imagesetter negatives and the K layer was considered essential.

Bob may not need the K layer if he prints with continuous tone film negatives, I really don't know. Guess he will just have to find out for himself.

Sandy

Katharine Thayer said:

Wow, I just learned something; I didn't realize there were premade tissues in cyan, magenta and yellow for tricolor printing. In that case, I would think that it would be much easier to print tricolor carbon than tricolor gum, where we're pretty much on our own with regard to choosing the pigments and the pigment concentrations to achieve a realistic color balance. I personally like the flexibility of choosing my own color palette, but I would think for someone interested in precise color rendition, that carbon with the premade tissues would take a lot of the uncertainty out of the color balance issue.

Click to expand...

Actually, there is no current source for pre-made cyan, magenta and yellow tissue for tri-color work. You have to make your own.

Also, it is extremely difficult to control color balance with the use of dichromate based sensitizers. Even two or three percent difference in density of any of the reliefs will throw color balance out of acceptable tolerances, and you can get this easily with different rate of drying of the three tissues eve with close humidity control in the drying room.

The Ultrastable color carbon system used tissues pre-sensitized with a diazo sensitizer, and control was much better.

Sandy King

sanking said:

Guess he will just have to find out for himself.

Sandy

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Guess so; every printer has his own personal preferences, but I was answering the general question why some really good tricolor gum printers don't find a black printer necessary: because they can get all the density, detail and contrast desired from three color printings.

Well, I'm new at gum, but here goes (and feel free to knock me on my a**)...

All the info you need to print color gum is in the RGB file, which we invert to get our separations...and printing gum in CMYK is very different colorwise from inverse RGB. I understand the truer color is had from inverted RGB.

CMYK really only applies to ink on a press, isn't that right? Also, I understand that converting to CMYK in PS loses the integrity of the file in some way IF the end target result is NOT press-related, ie, an inkjet or other color print.

The remarkable thing about Keith Taylor's prints are that they're 3 layer only prints, not layer upon layer of fine-tuning...think about that!

RGB is a much larger colour space than CMYK and you may lose something but I doubt it, just the same as LAB is a larger colour space than RGB.
I am always moving between modes for specific reasons, mainly rgb-lab , and back. I rarely move into cmyk.
The final ouput inks , dyes materials that are printed on really are the limiting factors , visually moving between the colour modes on a computer , one will hardly notice the differences on screen.
Though we work in RGB visually on PS , when files are moved to the Lambda*laser printer* for colour work we revert to cmy and d.ensity to correct and finalize the image, exactly the same way as traditional colour enlarging printing. keep in mind that we only can move two filters and if we use all three we are only adding nd.
I suspect and can be corrected that once I start separating files from lets say a RGB final tiff I will be making cmy separation B W negatives. I am at this stage now , basically I need to calibrate the bw film on my lambda with the 21step calibrator and make sure the I am happy how tone is being laid down on the film, then to the separation stage which I am not sure about yet but will get there.

PVia said:

Well, I'm new at gum, but here goes (and feel free to knock me on my a**)...

All the info you need to print color gum is in the RGB file, which we invert to get our separations...and printing gum in CMYK is very different colorwise from inverse RGB. I understand the truer color is had from inverted RGB.

CMYK really only applies to ink on a press, isn't that right? Also, I understand that converting to CMYK in PS loses the integrity of the file in some way IF the end target result is NOT press-related, ie, an inkjet or other color print.

The remarkable thing about Keith Taylor's prints are that they're 3 layer only prints, not layer upon layer of fine-tuning...think about that!

Click to expand...

Ok I know I am going on about the k mask and here is where my thinking is.

The K mask I believe can be used for a variety of reasons, in fact calling it a k mask may be the wrong terminology.
My main background is BW Silver printing using multiple filters.
before this I was a photocomp technician combining multiple images and colours.
With this background I like multiple hits on prints.

I believe if the registration issue is handled and three layers go down well then why not more hits on the prints.
I have found that there are two channels that are amazing for creating contrast and sharpening*no secret here* the L channel and the k channel.
therefore I would never sharpen on rgb , cmy, or ab colour but rather the detail channels.
I have seen the results of working on the L primaraly and would never consider global sharpening or curve shaping on all three colours at once.
So with this in mind I feel that specific k masks can be made that will enhance the sharpness of the final image or adjust the local or global contrast of an image, by adding this added hit after the three colours are down.
Why stop here? you may ask...
I also believe that in a lot of processes controlling shadow detail and highlight detail at the same time can be a difficult.
So why not make highlight detail masks that allow more information by an additional hit.
Also an additional mask for local colour enhancement or kicking in some deep blacks within already existing shadow areas.
the list goes on and on and I believe the key is having a support that will not shrink and basically you can just keep on building on a image .

Not for everyone I am sure but I think very possible and probably a lot of fun to figure out.

sanking said:

Traditionally a K layer was not used in making color carbon and color carbro prints when printing from continuous tone negatives, although I understand that a few top printers from the old days did use a K layer for certain types of images.

When the Polaroid color carbon and Ultrastable methods were introduced they were based on printing with imagesetter negatives and the K layer was considered essential.

Bob may not need the K layer if he prints with continuous tone film negatives, I really don't know. Guess he will just have to find out for himself.

Sandy

Click to expand...

More power to you, Bob, but a few thoughts on your way:

The difference between RGB and CMYK isn't just about the size of the gamut; it's in the profile and depends on the profile. Paul could well have been talking about the default Photoshop CMYK space, which has been widely recommended, very mistakenly, as a good way to make color separations for gum printing (Christopher James even recommends this in his book, although I haven't looked to see if it got into the second edition) and which does significantly alter the color values in the file. The default CMYK space is developed for high-speed web presses with SWOP inks on coated paper, and is totally wrong for gum. It removes color from all the color channels in order to move density into the black channel, but removes more from the magenta and yellow printings, leaving the color printings cyan-biased to adjust to the limitations and the requirements of the process inks and to move contrast mostly into the black printing. I made a page on this, back in the days when people were arguing with me about this, if you're interested. It's a bit wordy but I hope comprehensible; it goes through the CMYK settings and considers how suitable they are for gum printing, and takes a color and shows what happens to the color readings as you move from RGB to CMYK, and I think there's even a grey patch that's printed in gum from RGB>CMY separations and then from Photoshop CMY(K) separations; the "CMY" print shows the cyan bias that's built into the default CMYK profile.

http://www.pacifier.com/~kthayer/html/CMYK.html

I'm a little unclear as to what color space you're working in when you're creating the color separations. You say "I suspect and can be corrected that once I start separating files from lets say a RGB final tiff I will be making cmy separation B W negatives." Well, yes, but do you create the cmy separations manually from the RGB channels, which is the best way to do it (unless like Keith Taylor you have a special color profile that's been built for the pigments you use in gum printing) or do you switch into a CMYK space before sending the separations to the printer; if the latter, do you know what that CMYK space looks like and what it does to the color values in the channels during the mode change? These are important things to know.


As for sharpening in the L channel, yes, I was taught to do that too (by Dan Burkholder, I think) rather than sharpening in the color channels, but then you switch back to RGB after the sharpening, and the sharpening is retained. I guess I'd never thought until now to wonder how that sharpening translates back into the color channels when you switch back to RGB.

I've been printing tricolor gum for over 20 years. I generally prefer a muted color palette, a somber print and less contrast, (that's why I chose gum, so I could make color prints that didn't look like Kodacolor) so my prints may not impress you, but here's a sample of a few of my tricolor gum prints

http://www.pacifier.com/~kthayer/html/Gallerytricolor.html

and here's a demonstration print in brighter colors with more contrast, just to show that gum can easily do this in three color layers if one wants to; it's just a matter of the pigments you choose. The colors I've chosen for most of my tricolor gum prints have been rather dull, unsaturated colors to create the effect I want (PY110, PR 175, and ultramarine); in my experience the contrast, palette and color balance of a tricolor print has mostly to do with what pigments you choose and the pigment concentrations you print them at.

http://www.pacifier.com/~kthayer/html/optrans.html

Good luck, again,
Katharine

Katharine...your first paragraph above is indeed what I was referring to re: CYMK, and that inverted RGB does not equal CMY(K) when working within PS.

Bob, you raise some interesting questions and I'd like to keep abreast of your inquiry and solutions.

bob carnie said:

Hi Folks

I plan to mount my printing substrates to aluminum plates , to avoid shrinkage, and in the past I used a strosser punch system , and I wonder if anyone here knows where I can purchase a used one.

Click to expand...

Bob,

This is the source that Keith Taylor recommended to me for punch registration:

Dead Link Removed

Give them a call and tell them what you need to do and they can recommend the solutions they have.

I envy you for having the ability to make separations with the Lambda, they should be very sharp. I use digital inkjet negatives and they may not produce results quite as sharp.

For the record I primarily use CMY separations (sometines I will use CMYK using the K negative to alter the color of the black parts of the image, this is mainly for creative reasons not technical ones) and use Mark Nelson's PDN system to create unique curves for each layer. Keith Taylor uses ICC profiles to balance his separations if I understand his technique correctly. I would like to do the same since I have a friend locally who can produce high quality profiles using an XRite i1 spectrophotometer and software, though I'm still at a loss about how Keith and his color expert go about doing this exactly.

At any rate I can make perfectly color balanced images within limits - the color gamut is not as large as I would like and certain colors are very difficult to repoduce correctly. I also use cyanotype as the first layer for sharpness though you can use a pigment for that layer also. Since I don't punch register cyanotype first layer is my preferd method.

There are impurities in the pigments when printed together will normally create black (thought the reality is that the black won't be perfectly neutral.)

As far as sharpening the image goes I would recomend one of the software products like Nik Sharpener Pro or PhotoKit Sharpener. I use NSP and it is an amazing product which will save you money and time.

If you want to challenge yourself I recommend that you get a copy of the color version of Adobe's Ole Moire and learn to print that perfectly. You will learn a lot about your technique; this is what I recommend to my workshop students. By using this image you have a very carefully exposed image with a full gamut of color swatches and neutral grey scale. You also have no emotional attachment to the photograph to slant your judgment. I come from a proffessional photofinishing background (in another career long ago) so I understand the subtleties of traditional color printing which are helpful. Unfortunately I have no training in offset color printing which would be benficial understanding the CMY and CMYK workflow.

And for the record I print 1 layer per color when I'm making a "straight" tri-color gum. If you work carefully you can make very nice prints this way. My creative approach is to do most of what I want to do in Photoshop and then print the gum straight. This does not preclude having to use physical development at times. I develop my prints for 1 hour in 70F water though if I've got a problem print then I'll jump start the development with warm water (85F) for about 20 minutes.

I could ramble on but I think I've said enough for now.

Good luck,

Don Bryant