What amount of pigment should I use in carbon transfer printing process?

Hello, everybody

I've got a question about the amount of pigment that I should use for making carbon tissues. I mean, I'm definitely able to make tissues which give me a lot of relief even when the print is completely dry. And it's fine as long as I don't start making 2, 3 or 4 layers. In that case the paper starts to curl A LOT. As I was told by one person, the problem is using an amount of pigment which its too small.

So, I currently add 9 g of gouache to 300 ml of glop. I understand it's not enough, but how to calculate the starting point of a glop with a huge pigment load?

Thank you in advance,

Igor

Lightfire said:

I currently add 9 g of gouache to 300 ml of glop

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The problem with this is that there's just no telling how much pigment that is, exactly. In my limited experience with gouache, there's not a lot of actual pigment in it, but it'll depend greatly on the brand, product line and especially the color (due to the different tinting strengths of pigments).

But as a general rule, a 3% w/v 'pigment' load with the pigment being some kind of paint really isn't very low. In fact, if you'd do this with e.g. Winsor & Newton watercolors (to name a random, but well-known example), it would constitute a pretty high pigment load with high contrast and limited relief. The fact that you report a lot of relief suggests the pigment load of the paint you're using is very, very low indeed. to give you an example; I'm working with dry pigments that I disperse myself, and a typical pigment load for a Kremer Pigmente Pbk7 black tissue will be around 0.15% w/v (that's not a typo: far less than one percent!) at a gelatin load of 8% w/v. This is comparable to roughly a 1% v/v India ink 'pigment' load in my experience.

Note also that pigment load in itself means very little without information on gelatin load. Keep in mind your final transfer will be just pigment trapped in gelatin - al the water is gone from the finished print. So things like contrast and relief depend on pigment to gelatin ratio, not on pigment load of the watery glop!

Anyway, if you want to decrease relief, just increase pigment. Start by adding 25% or 50% and see where that gets you; adjust from there. There's no 'golden rule' for how much pigment one 'should' use. As said, it depends hugely on what kind of pigment in what form is used, and what your printing style is.

If you're doing multilayer prints, thinner layers tend to work best - not so much because of the paper curl, but mostly because of the problems you'll run into with air gaps/bubbles between consecutive layers.

Are you transferring each layer directly to the paper (single transfers on top of each other), or are you transferring the layers on top of each other onto a temporary support (e.g. a polyester sheet of some sort)? In case of the former, you'll get into trouble with registration issues, among others, at least going by my own experience. Paper isn't dimensionally stable and you'll experience increasing problems getting consecutive layers to align with previous ones. But as said, it may be challenging or even impossible to do a successful multi-layer dual transfer process with very thick layers.

So for all intents and purposes, I'd suggest going for thinner, more high contrast layers, and perhaps work around the inevitable highlight problems using multiple layers - which may be the reason for your multilayer approach in the first place? Are you doing a color process or a monochrome (or perhaps toned monochrome/polychrome) process?

Couldn't tell you how much but... it depends on pigment choice. With Daniel Smith lamp black I use 5g per 400ml glop ( I prefer to make small batches...that'll give me 4, 8x10 tissues, or 2, 14x17's). With India Ink (Speedball) I use 2g. I find if I expose more, I get curled prints. So, if you expose less, to maintain a black that you find acceptable, you'll have to add more pigment, and expose less... with the loss of some relief. Personally, I don't care too much about relief. It's quite subtle in mine, and that's just how I like it

Lightfire said:

Hello, everybody

I've got a question about the amount of pigment that I should use for making carbon tissues. I mean, I'm definitely able to make tissues which give me a lot of relief even when the print is completely dry. And it's fine as long as I don't start making 2, 3 or 4 layers. In that case the paper starts to curl A LOT. As I was told by one person, the problem is using an amount of pigment which its too small.

So, I currently add 9 g of gouache to 300 ml of glop. I understand it's not enough, but how to calculate the starting point of a glop with a huge pigment load?

Thank you in advance,

Igor

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3% is already a relatively high pigment load. There are lots of variables to consider, but you should be able to achieve tactile relief and good dMax with 15g of gouache per liter of glop (or even less) and tissue poured to a wet height of 1mm for a single tissue monochrome print.

The expensive stuff will have more pigment, as koraks mentioned. The bargain basement stuff is probably mostly fillers. You can pretty much use this rule of thumb for all art related materials.

I've decided to stop using the gouche, because it causes problems with gelatin dissolution when used in larger loads and also causes some kind of uneven texture/streaks.

So I used dry pigments (yellow ochre, ultramarine) for this work (but the magenta layer was still made with red gouache and I didn't like it at all). It definitely works better than I expected. But since there's still the problem with curling, I guess I should try adding even more pigment. That's not a problem tho, just a very interesting fact, I guess.

Here it is:

Lightfire said:

I've decided to stop using the gouche, because it causes problems with gelatin dissolution when used in larger loads and also causes some kind of uneven texture/streaks.

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That's my exprience as well. Watercolors work better, but are expensive. I switched to dry pigments, which are a bit more difficult to work with, but once you get the hang of it, it's not so daunting.

Great print! Is that a 6x6cm contact print from in-camera separations on 120 film?

koraks said:

That's my exprience as well. Watercolors work better, but are expensive. I switched to dry pigments, which are a bit more difficult to work with, but once you get the hang of it, it's not so daunting.

Great print! Is that a 6x6cm contact print from in-camera separations on 120 film?

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Thank you!

It's a 16x16 cm print from an enlarged negative printed onto x-ray film for CMY color separations (using RA-4 positives for contact printing onto x-ray film).

That's a fascinating workflow, and I'm impressed by what you're getting from it!
So you're doing the separations on RA4? I hadn't thought of that!

koraks said:

That's a fascinating workflow, and I'm impressed by what you're getting from it!
So you're doing the separations on RA4? I hadn't thought of that!

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It works pretty much fine and I'm able to get continuous tone negatives (unlike using halftone screen negatives from digital files). The backprint of RA-4 paper isn't a problem, actually. I mean, it doesn't affect the image at all. So I highly recommend to try this process!

It is interesting you use gouache, a more opaque paint than 'normal; watercolors. It would seem to block the layers below it and not allow the colors to visually mix as easily as the transparent watercolors.

Using RA4 as colored inter-positives is a fun idea!

Vaughn said:

It is interesting you use gouache, a more opaque paint than 'normal; watercolors. It would seem to block the layers below it and not allow the colors to visually mix as easily as the transparent watercolors.

Using RA4 as colored inter-positives is a fun idea!

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I though it would let me use less amount of paint 'cause gouache is opaque. But in reality it didn't work well. I mean, it could work well if it was a high-quality gouache, but I could only try some local stuff and it wasn't good at all. So yeah, I guess watercolors and dry pigments are better for such processes, but every pigment should be tested before using. It takes time, but hopefully I'll be able to get countinuous tone color prints, which have extended gamut and so on. I mean, halftone negatives are much easier to work with, but who cares if they still look like some polygraphy stuff when you look closer at the print.

Lightfire said:

It works pretty much fine and I'm able to get continuous tone negatives (unlike using halftone screen negatives from digital files). The backprint of RA-4 paper isn't a problem, actually. I mean, it doesn't affect the image at all. So I highly recommend to try this process!

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I was wondering about the backing print; I assumed you were printing on Kodak paper, some of which comes without a backing print. I suppose the ink is sufficiently transparant to UV!
Btw, I'd love to give good halftone negatives a try. They pretty much eliminate the highlight problem that continuous tone negatives suffer from.

Lightfire said:

who cares if they still look like some polygraphy stuff when you look closer at the print.

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You can't see a 20um or 40um mesh in the finished print, unless you use a microscope. Have a look at Calvin Grier's work. Forget about inkjet negatives for this, though - it takes an imagesetter to get such fine screens.

Lightfire said:

I though it would let me use less amount of paint 'cause gouache is opaque.

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I understand your reasoning, but when working with gouache, I noticed that gouache doesn't get its opacity from the pigment used (some pigments are more transparent than others) or from the pigment concentration. Instead, gouache contains a large amount of an opaque filler (something like titanium dioxide). Especially for cyan but also magenta, I tried a couple of gouache paints from two manufacturers across three brands. It turned out these paints contained less pigment than the watercolor paints from the same manufacturers, but a lot of white/opaque filler.

I have to rectify something I said earlier btw - gouache didn't give me transfer problems like you noted; that was acrylics. In high concentrations in a glop, I found that acrylic paints make the glop skin over unless it's stirred frequently. The acrylic medium tends to harden out if there's enough of it floating in the glop, and that creates problems. In low concentrations of around 1% acrylic paint, there are no problems in my experience. Likewise, gouache paints worked fine mechanically, but due to the opaque filler, saturation was way low and evidently the tissues were less transparent, which you actually do want for color prints.

For the best carbon compatibility, I'd recommend getting some concentrated pigment dispersions or pigment pastes. Here in Europe, they're sold by e.g. Kremer Pigmente in Germany and of course Calvin Grier sells them specifically for alt. process printmaking from his base in Spain. I suppose there must be sellers of pigments and pigment pastes in Russia as well, but I don't know anything about them personally.

koraks said:

it takes an imagesetter to get such fine screens.

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There's a place here which uses an imagesetter with such a small dot, but the problem is not the size of the dot, but the amount of dots per cm. Calvin Grier probably has a better imagesetter ofc, but he also has to use 2-3 negatives for printing one layer, because it fixes that problem or at least makes it better. I guess it may be improved in my situation, but it'll take some time to help the guys with calibrating their imagesetter.

koraks said:

I suppose there must be sellers of pigments and pigment pastes in Russia as well, but I don't know anything about them personally.

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It's possible to find dry pigments here, I guess it's enough for me for now. If I learn how to work with them properly I'll be able to get consistent results.

Lightfire said:

the problem is not the size of the dot, but the amount of dots per cm

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I was referring to anamplitude modulated screen with a 20um or 40um dot pitch . Grier uses AM for most layers AFAIK. At a 40um pitch that's 250 lines per cm or ca 625lpi - you're not going to see that with the naked eye or even a low magnification loupe.

koraks said:

Grier uses AM for most layers AFAIK. At a 40um pitch that's 250 lines per cm or ca 625lpi - you're not going to see that with the naked eye or even a low magnification loupe

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That's actually interesting. I tried both FM and AM (but only 200 lpi) and liked the FM more. But I'll make a test with AM 400 lpi for sure. It's the highest lpi value I could find here

200lpi is already pretty nice. It'll be just visible to the naked eye if you look closely and have good eyesight. Anything beyond should be pretty darn smooth.