Letterpress Inks

In the last few days several people have mentioned Magnesium Carbonate as a bulking agent to thicken inks that have been manufactured for offset printing, as nearly all commercial inks are today. I am curious as to where this information is referenced, as I cannot locate a reference to it used for this purpose in any of my books about printing inks. The most comprehensive book on the subject, “The Printing Ink Manual” published by The Society of British Printing Ink Manufacturers, makes no mention of it at all.

I do find Calcium Carbonate mentioned frequently as a bulking agent and extender in the literature, but not Magnesium Carbonate; which leads me to wonder where the use of it for that purpose originated. Calcium Carbonate, also known as Whiting is frequently used in the paint and varnish industry to thicken paints, and more as an extender for printing inks, because properly made letterpress inks would use a heavier grade of varnish and paste waxes to get the paste-like quality that seems to be missing from inks we purchase today.

When I lived in Nashville I had a number of conversations with ink manufacturers about the manufacture of inks for letterpress, and the adaptation of offset inks for letterpress purposes. One veteran maker stated that in the ‘old days’ they would add corn starch to add bulk, and I have added it, and rice and tapioca starch at times to thicken the ink with varying results. The problem with adding any powder to an existing ink without grinding is that the powder can make the ink grainy, and leave the printed surface rough with a sandpaper quality.

It used to be that ink manufacturers would carry different inks for different purposes, but today it seems that one size fits all mentality has taken over that industry as well. If we have to learn to adapt to inks that are formulated for high-speed offset machines it might behoove us to learn about ink manufacturing and how to adjust the inks without destroying their good properties.


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Hi Paul -

I took your previous post(s) to heart and did a little research as I have used magnesium carbonate, corn starch, and body gum.

I found this from the American Pressman:


I agree that it would be helpful to have an authoritative resource, but unfortunately much of the information relates to materials that were available at the time of print and are only an indicator of what we should be looking for today.

It would be nice to have a concise resource to conform currently available commodity ink to be optimum for letterpress purposes.

Thank you for your posts…

Thanks for posting the link, it sure describes some of the problems found in the pressroom, but is a little light on remedies. I wish I had access to more of the old journals, there is so much to learn.

I used to be able to purchase the inks I needed for letterpress just by picking up the telephone and talking to the supplier at Inmont or Keystone, or whichever supplier I was using at the time. So may of the suppliers have been bought up by large corporations, and are now staffed by chemists who never had to deal with letterpress demands. When the old guys retired their wealth of knowledge went with them, and unless you are a major client the new breed has no incentive to offer special attention.

I have doctored ink for 30 years, and have a shop filled with inks I have scrounged from closed shops, some inks dating back 40+ years. I have learned how to extra-mix pre-mixed inks to get a color I need, and dealt with inks during all seasons, and all kinds of stocks. I look at it as a challenge to make the ink do what I need it to.

It is hard to be encouraging to beginners that are using bad paper and inks that were formulated for a hi-speed press, if the solutions become more expensive that the job they are attempting to print. But that is the way printing is, sometimes you can attempt a dozen complex solutions before discovering that it was a simple mechanical oversight.


Hi Paul-Handbook of Lithography 3rd edition 1948 revised ,first edition 1905 by David Cumming(an ex chief examiner for Lithography in Edinburgh), oxide of magnesium(calcined magnesium) used to adsorb the greasiness in ink……….

From Wikipedia: Magnesium Carbonate
The primary use of magnesium carbonate is the production of magnesium oxide by calcining. Magnesite and dolomite minerals are used to produce refractory bricks. MgCO3 is also used in flooring, fireproofing, fire extinguishing compositions, cosmetics, dusting powder, and toothpaste. Other applications are as filler material, smoke suppressant in plastics, a reinforcing agent in neoprene rubber, a drying agent, a laxative to loosen the bowels, and color retention in foods. In addition, high purity magnesium carbonate is used as antacid and as an additive in table salt to keep it free flowing.
Because of its water-insoluble, hygroscopic properties MgCO3 was first added to salt in 1911 to make the salt flow more freely. The Morton Salt company adopted the slogan “When it rains it pours” in reference to the fact that its MgCO3-containing salt would not stick together in humid weather. Magnesium carbonate, most often referred to as ‘chalk’, is used as a drying agent for hands in rock climbing, gymnastics, and weight lifting.
As a food additive magnesium carbonate is known as E504, for which the only known side effect is that it may work as a laxative in high concentrations.
Magnesium carbonate is also used in taxidermy for whitening skulls. It can be mixed with hydrogen peroxide to create a paste, which is then spread on the skull to give it a white finish.

The description of Magnesium Oxide and its uses are not even applicable to printing ink additives.

Ralph Mayer in his book The Artist’s Handbook of materials and techniques describes Magnesium Carbonate as an inert pigment used at times for an additive to gesso, and as an additive used to create a rough or mat effect in varnishes, “…it sometimes may be added in very small amounts to a wax-finish varnish to improve its flat quality, usually at the expense of some of its transparency.”

I’m still not convinced that it is generally used as a bulking agent in printing ink. I see it mentioned as a drier or a dusting powder, but that is not the same.

Hello all, I have been printing as a career and setting up my letterpress venture. I contacted a long time friend and ink chemist who is well skilled in the mysteries of printing ink making. He’s going to give me a list of additives and proportions needed to modify offset inks to letterpress use. I will gladly share info when I receive it he is very knowledgeable in ink and has saved my bacon in the past
Fraternally - Ted Lavin

I have used calcium carbonate for “shortening” ink for use with halftone printing. If the ink “strings out” (holds to itself too well) it will leave extra ink around the image dots and not print sharp and clean. It is better to have an ink which is short to begin with, but as Paul indicates, those inks are increasingly difficult to find.

Another product which is recommended by some ink manufacturers is Fumed Silica. One of the trade names is Cab-O-Sil made by Cabot, and one of its specified uses is for viscosity control in paints and inks. This material is very fluffy powder with practically no weight. It can be added in good quantities without having an effect on the drying properties of the ink, and mixes in quite well since the particles are so small (no grainy appearance in the final ink film, although it can lower the gloss). Some ink supply companies (look for screen printing ink suppliers) can provide this in small quantities, otherwise it is only available in large bags from the manufacturer. I hestitate to mention it as, being a silica product, it must be handled very carefully until mixed with the ink as it can be inhaled and would be a respiratory irritant.

A quick search for Cab-O-Sil on the web will net you many places from which the material can be obtained in fairly small amounts.

Like Paul, I remember being able to order letterpress inks from the ink companies who used to have agents and warehouse/mixing facilities in major cities. My favorite was Lewis Roberts who had an office in Tulsa Oklahoma when I was teaching in Stillwater, OK. You needed to let them know what type of paper you were printing on as they would formulate the ink for uncoated or coated paper and had special formulations for general job printing, halftone printing, or large image flood coverage. These days, you must do the adjustments to the ink yourself, and you will find that one ink company’s products in the same line of ink will have various body characteristics based on color or pigment type, and, in my experience, they don’t generally do a very good job of adjusting the body of the ink for uniformity.

John Henry
Cedar Creek Press

Inhaling silica can cause a disease called silicosis. Basically the silica goes into your lungs and sits there cutting your lungs up. I used to work at stained glass, and listened one quiet day to my boss’ labored breathing. I decided it wasn’t worth the risk and went back to printing.


I shall add my two-cents-worth to this magnesium carbonate discussion. I am a printmaker who has regularly used magnesium carbonate in inks for stone lithography, intaglio etching, and relief (woodcut/linocut) printing since 1970. ‘Mag’, as it is known in most fine art print shops, will add bulk to any ink, reduce its viscosity (making it less oily by absorption), shorten its length, and decrease its tack. It is invaluable in hand-printing stone & aluminum-plate lithography, in helping to adjust all ink properties, and it prevents scumming of the image during printing. The rule in litho is to only add up to a maximum of 10-15% by volume to your ink; too much mag can make the ink too ‘floury’ causing it to lose ability to properly adhere to the paper (and a host of other problems) resulting in a weak, grainy impression. A good analogy, for those who are familiar with baking, is to think that adding mag to ink is like adding flour to cookie dough. Adding mag to oil-base letterpress inks is fine; just stay within or below the 10-15% max. rule to adjust the body/length/tack/viscosity of the ink until it is compatible with your selected paper. I do not know how it would respond to rubber-based inks however. I hope this is helpful. Happy printing.

Calcium carbonate, fine starch powders, even arrowroot powder will add bulk to long inks at the cost of density of the colour and as referred to above will make the ink go gritty if the particles of powders are too large . The carbonate additive are extremely fine in inks ,it is milled to a very smooth dust , the location or sourcing of really fine powder is difficult so the effects noted above are due in the main to the size of the grains of additive being too large or just adding too much of the stuff . There are many problems created by changing inks with solid additive , it increases wear on the type and print face in letterpress , not so troublesome in short run work but when you get up the scale to 50k runs it was an issue , in litho the same problem occurs and the plates can scrub out ,the image wears away and the anodizing wears through although it depends whos plates you have and the areas of image on it .

@sandrasam. Do you have a written source that guided you to using Magnesium carbonate? I am trying to determine the source of its use, since it doesn’t seem to come from industry sources.

Try the Tamarind Insrtitute’s handbook on Lithography
or Stone Lithography by Paul Croft

Although neither are letterpress texts- both of these texts have a section discussing the modification of inks, Mag is covered in both I believe (although I don’t have a copy of Paul Croft’s book).

I don’t know if you’d find it in commercial printing handbooks or texts as readily or not.
I come from the fine art side of printing education which doesn’t stress rigorous laboratory testing or mass production/dependance on suppliers like you guys are talking; with regard to mixing one’s own ink, I feel like fine art printing as a background may be more geared towards modification in small amounts anyhow rather than buying it from a supplier who mixes/mills it for you.

Most people printing letterpress even on a small scale would not wish to mix their own inks from scratch, and I doubt that many artist printers would wish to either, although the artist printers might have a better idea of the subtle adjustments needed to make ink work correctly. I would suggest that art printers are even more concerned about the quality of their inks, i.e. permanence, lightfastness and workability than most letterpress printers who know little of what actually goes into the ink they use, but prefer it to work well right out of the can.

Since I don’t have ready access to etching and lithography manuals I hope that others who do would check theirs to help pin down the reason that Magnesium Carbonate is preferred over Calcium Carbonate, or if they can be used interchangably. It just seems odd to me that when I look in commercial printing references I find one thing, yet online and on this site I find the other. It might not matter which is used, but I would think that chemically there is a reason for one or the other.

Unfortunately we live in a time when the subtle needs of letterpress printers are basically ignored by the manufacturers who used to be the constant in our printing equation. Paper and ink changed very little throughout most of the 20th century, and it has been only in the last 30 years or so that our needs as printers have become unimportant. Now that the best and most affordable papers come from a handful of manufacturers in Europe, and I would assume the best inks do as well, we find ourselves having to “make do” with what is offered by the corporations that have bought up the small suppliers that once dotted the countryside.

Once an ink is reduced for flow on the roller stacks of offset machines it is hard to return it to a consistency that is appropriate for slow moving letterpresses. Yet this is a challenge we have to face daily, or be satisfied with a printed product that is not as good as it could be.


Hey man, Mag works for me. I’ve been doing it for years and it’s been used with success by many art printers running slow letterpresses. It goes into the ink easily and works wonderfully.

Why don’t you give it a try?

I’ll try cornstarch sometime and let you know what happens.

I wouldn’t use cornstarch unless you have a muller or mill to work it into the ink, the particles are too large to suit me. I think I will have a conversation with an ink chemist and see what they have to say before I use Magnesium Carbonate. I’ve found that the word of mouth references aren’t always the right recommendations, which is why I’m searching for the proper documentation.



Works for me as well. Walter Hamady used it. Can’t argue with that.

Cornstarch is not as finely milled, you will be disappointed.


OK so I’ll stick to Mag then :-D

just wondered if it is worth setting up on Briar in a reference section somewhere (rather than trawling though previous posts)a definitive suppliers/manufacturers list of decent letterpress inks for U.S. and E.U.(eg Pro line Caslon Adana, Vanson, Lawrence), it might encourage them to keep making if users can interact and score by recommendation if you see what I mean……plus a list of “others” that “can” work eg stone litho inks like Hawthorn, Joop-Stoop, Graphic Chemical , AMRA.ch , Hanco,
and the best of commercial offset inks that can be made suitable,maybe some other relief inks as people print images too on handpresses…….looking forward to the list of additives/components from Ted Lavin, thank you!

I think it more likely something like that would be set up on letterpresscommons, perhaps at https://letterpresscommons.com/types-of-inks/

Paul, Graphic Chemical has a 1920’s formula letterpress
ink. In my opinion its good stuff. Gustave Baumann and Willard Clark mixed their own colored/pms inks from scratch but those guys are long gone. Willard’s grandson
does restrikes from the original blocks and still mixes ink
the way Willard did. Yes, we live in a time a rapacious
corporate mentality and there is nothing in their way.
best james


I prepared the original section on inks for Letterpress Commons, and tried to keep brand names out of the document, rather trying to talk about various types of inks and additives. If someone wants to add a more detailed description of various inks by brand name, I think it would be well received. You just have to be careful it doesn’t become a place where complaints are filed, as one person’s experience with a particular ink may or may not be representative of someone else’s experience.

It would be certainly valuable if people would list sources for the inks, and retailers.

John Henry

I have heard of using corn starch when I was involved with offset - in the back of my mind I always figured I would fire someone who attempted that. Also I recall hearing about veggie shorting as a tack reducer, pressmen would tell me that it was all natural and wouldn’t cause problems - that was a large line of BS. Tell your ink salesman what you want, what you’re printing on, how you’re going to use it and what tack you want, this will solve many issues. A triple beam and a bag of chemicals may not be the answer.

thought people might be interested in this U. S. list of ink suppliers link,

“Tell your ink salesman what you want, what you’re printing on, how you’re going to use it and what tack you want, this will solve many issues. A triple beam and a bag of chemicals may not be the answer.”

That would be well and fine for printshops who order lots and lots of ink.

…. However, the vast majority of people printing and practicing letterpress don’t have “an ink salesman”. They buy very small quantities retail ‘off the shelf’, and it’s my understanding that the amount of companies supplying ink are dwindling.

Going back to the OP


I use Magnesium Carbonate as a stiffener (a viscosity changer). I have never before heard of it as a bulking agent. Any references I have found on (that I trust) came from the fine press book printer or printmaking community, not from a discussion list, which I tend not to trust, simply because folks don’t really identify themselves, so there is no real trusted reference.

It is ground quite fine so I don’t detect graininess in the ink.


Today I had two conversations with technicians at Gans Ink in Los Angeles and Western Ink in San Francisco. Both men offered that they make ink to your specifications and your needs, and that it is the best way to purchase ink, rather than buying an ink off the shelf (usually formulated for offset) and trying to manipulate it after it has been formulated. Both companies sell ink by the pound and do their best to satisfy their customers, as any ink company would.

Both said that when letterpress had a larger place in the market calcium carbonate was used to bulk the ink for certain customers, but that it was unnecessary for an ink which had been formulated correctly in the first place. They both said that keeping calcium carbonate on hand to adjust inks when necessary is helpful, but should always be a last resort. Calcium carbonate fell out of general use when the industry moved primarily to offset because its use could cause plate blindness, and other additives worked better. Magnesium carbonate was used occasionally, but not for the same reasons, and was considered more of an extender than a bulking agent. [Changing the consistency of ink by overusing extender can affect the pigment dispersion, make the pigment seem weak.]

Most of the references I have managed to find concerning magnesium carbonate consider it as an additive to help absorb the excess oils in etching and lithographic inks, and as an over-spray for drying, or as a neutral pigment or extender. This is not to say that it doesn’t react as a thickener when added to ink, but it doesn’t appear to be its primary, or even secondary use.

I will again offer that developing a working relationship with a local or regional ink manufacturer will benefit any printer. Modern ink chemistry is far more complex than it used to be, and both men said that to avoid printing problems such as those that initially started this conversation it is better to purchase the right ink for the job than to try to doctor an ink that is not working properly. But it would be good to keep some calcium carbonate on hand for those times when one does not have access to the ink needed.