Tintenlabor Rothorn

[yazeh]

Tintenlabor Rothorn

 

Ink Review # 224

 

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🧾 Description

 

Tintenlabor is a Swiss ink company specializing in iron gall inks. What differentiates these inks from other brands is that the iron content is clearly stated. The highest iron content in the range is 6 g/L, and the lowest is 1 g/L.

The samples were sent to me by the Ink-Meister, David.

Rothorn is a German term that translates to “Red Peak” and is commonly used as a name for various mountain summits in the Alps.

Rothorn has an iron content of 4 g/L.

It is a wet, well-lubricated ink: bright red when wet, oxidizing into a dark burgundy or red-black depending on nib size and paper. It has good water resistance; the more the ink cures, the more waterproof it becomes.

Oxidation is immediate on Iroful paper, and slower on Midori and Tomoe River 68 gsm paper.

The ink is very well-behaved on copy paper.

As a writing ink, Rothorn shines with wider nibs. As a drawing ink, it requires more time to cure than Basalt when used for line work.

For cleaning, it is best to add a small pinch of pure ascorbic acid to water. Never use ammonia-based cleaners with iron gall inks.

I’ve been impressed by these newly formulated inks, which offer excellent lubrication and wetness.

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🧪 Chroma

 

 

 

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✍️ Writing Samples (scan)

Rhodia / Iroful

 

 

 

Midori /Tomoe River 68gsm

Note: Tomoe River used here is 68 gsm, not the thinner 52 gsm version commonly referenced in reviews.

 

 

 

Hammermill 20lb  

 

 

 

 📸 Photo

Rhodia/ Iroful

 

 

 

Midori / Tomoe River 68 gsm

 

 

 

Hammermill 20 lb copy paper

 

 

 

 

Wet ink

 

 

 

 

Closeup – A month later. 

 

 

 

 

 

 🔍 Comparison

Col-O-ring. Scans are approximative. 

 

 

 

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 💧 Water Test

Note how water resistance improves after 48 hours. 

 

 

 

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 🎨 Artwork

Rothorn

Cat and mouse are present but in rock formations

 

 

Mouse knows best!

Jacques Herbin Gris Galet, Tintenlabor Rothorn, Monteverde Caribbean Blue, Pelikan Edelstein Apricot Achat, Talens Mixed Media Square Sketchbook.

 

 

The Red Horn Incident!

Inspired by my own linguistic mishap of Rothorn, which I first read as Red Horn. 😁

 

Kattr the Red Horn warrior attacked Rothorn, offended that his illustrious name was being misused. There could be only one strongman worthy of such a title.

But when the Alpenhorns blared from the mountains that bore this name, Mús the Magus said dryly,

“You should have studied linguistics before pillaging.”

 

Tintenlabor Rothorn & Tannenwald (green), J. Herbin Bleu Calanque, Uni-ball Signo White Gel, Talens Mixed Media Notebook.

 

 

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- Pens Used: Pilot Kakuno EF, Kaweco (EF/F/M/B/ Stub 1.9), Osmiroid Copperplate nib. 

- What I Liked: Lovely oxidized colour. Excellent drawing ink. 

- What I Did Not Like: Needs more time to become waterproof. 

- What Some Might Not Like: Fear of IG ink; Using it in expensive pens. 

- Writing Experience: Excellent.

- Pros: Waterproof, retains colour, well-lubricated. 

- Cons: Tariffs for some countries. Not wildly distributed. 

 

 🧷 Ink Characteristics

 

- Shading: Excellent. 

- Ghosting: Very faint. 

- Bleed Through: Faint. 

- Flow Rate: Average. 

- Lubrication: Excellent. 

- Nib Dry-out: Did not notice. 

- Start-up: Very good. But needs a well-sealed pen.

- Saturation: Deliciously saturated. 

- Sheen: No. 

- Spread / Feathering / Woolly Line: Did not notice.

- Nib Creep / Crud: Did not notice.

- Staining (Pen):

- Clogging: No.

- Cleaning: Relatively easy. A pinch of ascorbic acid can help. 

- Water Resistance: Very good after 24 hours, won’t budge after 48. 

 

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 🛒 Availability

 

- Available in 30/50 ml bottle from Tintenlabor website: 

https://tintenlabor.mycommerce.shop/products/rothorn

 

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 💬 Closing

 

I have been using and testing a lot of iron gall inks in 2025. What I’ve learned is that these inks are suited for those who use pens that are well-sealed, can be easily dismantled and use them regularly. I still don’t get tired of the colour transformation. These inks give a new meaning to the expression, watching ink dry.

 

No fountain pens were hurt in preparing this review.

 

Please don’t hesitate to share your experience, writing samples, or any other comments — the more the merrier.  

 

 

 

 

[LizEF]

Great review, @yazeh!

 

That chroma is very cool. The color is interesting, though I don't know that I'd particularly want it. Wonderful shading, though.

 

That first watertest drawing is giving me Indiana Jones vibes.

 

Love the drawings, especially The Red Horn Incident! 

 

Thanks for bringing a bit of fun, interest, and inky joy to our little world.  

[yazeh]

19 minutes ago, LizEF said:

Great review, @yazeh!

Thanks.

19 minutes ago, LizEF said:

That chroma is very cool.

It's amazing. He has another one in the works, which has this type of @Sailor Kenshin chroma.

 

19 minutes ago, LizEF said:

The color is interesting, though I don't know that I'd particularly want it.

It's for those who love the colour burgundy.

 

19 minutes ago, LizEF said:

Wonderful shading, though.

This is where we discover that there is shading and shading. 

19 minutes ago, LizEF said:

That first watertest drawing is giving me Indiana Jones vibes.

I did that when I was still in my red horn incident.

19 minutes ago, LizEF said:

Love the drawings, especially The Red Horn Incident! 

I did the initial sketch in early December. I finished it last night for the review.

 

19 minutes ago, LizEF said:

Thanks for bringing a bit of fun, interest, and inky joy to our little world.  

These words make me so happy,no want to .  :) 

 

 

 

[LizEF]

1 hour ago, yazeh said:

This is where we discover that there is shading and shading. 

 

1 hour ago, yazeh said:

I did that when I was still in my red horn incident.

 

1 hour ago, yazeh said:

These words make me so happy,no want to .  :) 

 

[Sailor Kenshin]

A falling dragon with his head on fire?  No wonder he's pulling a sour face.

 

Cool artwork!

 

Thanks for the review, @yazeh.  These iron galls may not be for me but I always enjoy the show!   👏🏻

[inkstainedruth]

@yazeh -- This one has definitely piqued my interest.  But don't know how easy the Tintenlabor inks are to get here in the US (there are some other ones I've seen that I also was going, "Oooooh" about as well).

I did also have a question -- I gather that for some of their inks, they list the amount of IG component in the ink, and was wondering how much was in in this one (especially since some of your images show it going completely black in the "wet" test).  

Ruth Morrisson aka inkstainedruth

[LizEF]

23 minutes ago, inkstainedruth said:

I gather that for some of their inks, they list the amount of IG component in the ink, and was wondering how much was in in this one (especially since some of your images show it going completely black in the "wet" test).  

 

On 1/26/2026 at 1:05 PM, yazeh said:

The highest iron content in the range is 6 g/L, and the lowest is 1 g/L.

....

Rothorn has an iron content of 4 g/L.

 

[yazeh]

8 hours ago, Sailor Kenshin said:

A falling dragon with his head on fire?  No wonder he's pulling a sour face.

 

8 hours ago, Sailor Kenshin said:

 

Cool artwork!

Thanks!

8 hours ago, Sailor Kenshin said:

 

Thanks for the review, @yazeh.  These iron galls may not be for me but I always enjoy the show!   👏🏻

Most welcome. Thanks for your support. It keeps me a going. 🙏

[yazeh]

 

2 hours ago, inkstainedruth said:

@yazeh -- This one has definitely piqued my interest.  But don't know how easy the Tintenlabor inks are to get here in the US (there are some other ones I've seen that I also was going, "Oooooh" about as well).

At the moment, the only way is to order directly from Switzerland via the Tintenlabor website. The site is in German, but you can use your browser’s built-in page translation to navigate it. I can’t comment on U.S. customs fees or tariffs, since I’m not in the U.S., but Swiss Post is very efficient — I usually receive my packages in about a week.

2 hours ago, inkstainedruth said:

I did also have a question -- I gather that for some of their inks, they list the amount of IG component in the ink, and was wondering how much was in in this one (especially since some of your images show it going completely black in the "wet" test).  

Ruth Morrisson aka inkstainedruth

@LizEF responded to that. As of now, most of the inks have 4 g/L iron content.  

Not all 4 g/L inks oxidizes to black. For example this one has kept it's burgundy colour after 1 month. The oxidation depends on many factors: Paper, concentration and amount of ink on paper, dye, humidity to name a few. 

For some reason IG ink oxidizes immediately and strongly on Iroful. Whereas the process is slower on Midori and copy paper. 

If I use a wet EF flex nib, the oxidation can go directly to almost black.  However, with a M , B, Stub nib the oxidation is often slower.

It's funny when you see the colour of the ink the convertor (bright red), coral on the paper and the transformation to burgundy. The process makes it tricky for drawings, as I have to think of the final oxidized colour and not what I see. 

Now the red/ pink /purple dyes don't oxidize as much as the green ink, which I'll post in a few weeks.  Hope this answers your questions.

 

 

[yazeh]

@LizEF thanks for the music and the answering Ruth. .  🙏

[LizEF]

34 minutes ago, yazeh said:

@LizEF thanks for the music and the answering Ruth. .  🙏

[inkstainedruth]

And thanks to BOTH of you for the information!

I'm now wondering if the difference between the results on the Iroful paper and some of the other ones has to do with the pH of of the paper (oh, if we had only done INTERESTING things like that in my high school chemistry class -- it was bad enough that I got paired up with the derpy guy who sat next to me (and who I think was convinced that girls couldn't do "science-y" things, but I don't think he realized that I had a higher grade point average than he  probably did).  I don't know how he ranked in our graduating class, either, but I was 9th overall, grade-wise....  And just betting he wasn't NEARLY as high....

Ruth Morrisson aka inkstainedruth

[yazeh]

@inkstainedruth as our resident chemist is caught in a ice alter, I asked Chatgpt to formulate a coherent theory. However take it with a grain of salt, as I can't guarantee it's veracity. ( the last time I read anything chemistry related was around  500 B.C. so it doesn't amount to much.  )

 

"Iron gall darkening is governed by the oxidation reaction
Fe²⁺ → Fe³⁺, which is controlled by oxygen availability, local pH, and ion mobility.
While alkaline pH accelerates this reaction, it is not the dominant variable across different papers. The rate-limiting factor in practice is where the iron ions reside after deposition.
Papers such as Iroful retain the ink as a surface film. This maximizes exposure of Fe²⁺ to atmospheric O₂ and often coincides with alkaline buffering, producing rapid and high-contrast oxidation.
Tomoe River 68 gsm has a very dense fiber network that holds ink near the surface plane, allowing oxidation to begin earlier despite slow drying.
Midori MD (Codex) allows deeper fiber penetration. Once Fe²⁺ ions are sequestered within the cellulose matrix, oxygen diffusion becomes limited, and oxidation is delayed, even if bulk pH is similar.
Therefore, differences in oxidation rate between these papers are better explained by ink penetration depth, fiber density, and oxygen diffusion kinetics than by paper pH alone. "

[inkstainedruth]

Okay, I SORT of understood parts of that (especially the "deeper fiber penetration" part.  But you have to remember that I haven't had a chemistry class since maybe the mid 1970s....  And because of a scheduling conflict (which didn't put me in the math class I was supposed to be in, had to completely re-arrange my class schedule.  Which meant that I had chemistry in the last period of the day, and there were only 2 other girls in that class, and a good chunk of the guys were all sweaty and disgusting from having just come from a gym class....  

And it didn't help that the chemistry teacher was a jerk....  One of the other girls (who was a year ahead of me) had just gotten accepted into the Air Force Academy (that was when they first started accepting girls into places like that and West Point.  And he made some joke about her, and the other girl in my class (who tended to wear a long military coat even indoors) -- forget what he said about HER now -- and then (because my parents thought nothing about dragging my brother and me out of school a couple of times a year to go on trips overseas) looked at me and  and said, "Oh, and YOU'RE the foreign correspondent...."

Like I said, that teacher was a jerk....

Now, if we had been doing stuff like the pH of paints and inks, I probably would have paid a LOT more attention, and enjoyed the class more....

Ruth Morrisson aka inkstainedruth

 

ETA: But would have STILL probably thought my lab partner was a complete and utter putz....

[yazeh]

@inkstainedruth I can tell many of my teachers were overworked, underpaid "jerks" who had to deal with overflowing classrooms. But there were a few who managed to give me hope. I wish there were a class about life lessons, and how to deal with how things are and not how they should be. That would have made life much easier. 

As for your lab partner, he was probably insecure and said that to hide his inadequacy.  If it helps, I apologize for his behaviour.  

 

I asked Chat to make a simplified version: 

 

Iron gall inks darken when the iron in the ink reacts with oxygen. Paper pH can influence this, but it isn’t the main reason different papers behave so differently.

What matters most is where the ink ends up. On papers like Iroful, the ink stays on the surface, where it is exposed to air, so the color darkens very quickly. On Tomoe River 68 gsm, the ink stays close to the surface, so oxidation still starts relatively early, even though drying is slow. On Midori MD (Codex), the ink sinks deeper into the paper fibers, which limits contact with air and slows the darkening process.

So the differences you see are mostly due to how each paper holds the ink and how much oxygen can reach it, rather than paper pH alone.

[inkstainedruth]

Yeah, the guy probably WAS insecure -- he was a really big guy but not (I think) remotely athletic.  Doesn't excuse the behavior, though -- especially towards someone who was ALREADY routinely picked on all through school (I was tall, skinny, smart, wore glasses and wasn't remotely athletic -- so definitely not one of the "cool kids").  

Of course, if anyone had told me back then that someday I WOULD be "one of the cool kids" (both in this hobby and my other one -- where I now have the top service award [blink] and also got an award that very few people who WEREN'T ever regional or corporate officers have ever gotten) -- I probably would have laughed in that person's face....  The paperwork for the "special" award is finally going through, after having somehow gotten lost in the shuffle for nearly a year and a half and I'm tempted to start a survey as to who else has gotten that special thing and how many of them were like me and WEREN'T regional or corporate officers (I did do a stint, many years ago, under a couple of regional officers as "Staff Artist", and then worked for a friend of mine who did two years as a corporate officer, mostly helping with reorganizing the file drawers because they were delivered to her in deplorable condition (the staff for her predecessor apparently got tired of going down in that person's basement... ).  So, something like 18 file cabinets were delivered to my friend's house and a bunch of us had to re-alphabetize all the files (there was another person on staff who was absolutely convinced I knew EVERYBODY in the organization -- even if I knew two names in a three foot deep file drawer...  -- and she didn't understand that I didn't even know everyone in our local chapter...).

Ruth Morrisson aka inkstainedruth