Tag Archives: #inkfast

Iroshizuku Ink Gets UV & pH Tested

No one should be surprised by the meteoric rise of Iroshizuku inks on the fountain pen scene. Japan’s finest ink makers have created dozens of colors and hues that offer vibrancy and shadowing while never clogging a vintage or modern fountain pen.

We picked up 24 bottles of this amazing ink and have submitted them to our rigorous UV and pH testing. Each of the following inks was placed in one my sunniest windows between July 16, 2021 and October 16, 2021. We calibrated our pH meter and tested these inks at 75.6ºF at 50% humidity. As a quick reminder, on a pH test, 0 is the extreme limit for acidic, 7 is neutral and 14 is the extreme end of alkali or base. Click the individual photos for a closer look.

In many of our tests, blue inks tend to be very susceptible to UV light. Not Iroshizuku! Unfortunately, many of its other colors fade badly. The images certainly explain more than I can. Nevertheless, I love the peachy salmon of a late summer sunset that is Fuyu Gaki ink, and like a sunset it fades almost entirely. The nearly emerald green of Shin Ryoku turns turquoise. The blue-black Fuyu Syogun turned a light-fog grey. And the black Take Sumi stayed dark but turned dark brown.

When it comes to pH, these are simply raw data points. We do not know specifically how they interact with the chemistry of the ink sacs and piston parts of your pen. Most of these Japanese inks are on the shallow end of the base depth chart.

Color                        pH
Murasaki-Shikibu  8.1
Chiku Rin                 8.8
Shin Ryoku              8.4
Juro Jin                    9.0
Shin-Kai                   8.4
Asa Gao                    8.4
Fuku Gaki                8.6
Yu Yake                    8.5
Kosa Mosu               9.1
Momiji                      8.9
Tsutsuji                    8.7
Yamabudo               9.1
Ku-Jaku                    8.5
Tsuki-Yo                   8.5
Ama-Iro                    8.8
Fuyu Syogun           8.5
Kiri-Same                9.0
Kon-Peki                  8.7
Tsuyu-Kusa             8.7
Aji-Sai                      9.2
Tsu Kushi                9.0
Ina-ho                      9.0
Take Sumi               8.3

A Potpourri of Ink Tests

As we have been conducting our ink tests, we ran into a grouping of mostly orphaned bottles that wouldn’t make for a very big story individually. So we tested them together and got them all on one page.

The ink proof sheet is on the left and the UV tested inks are on the right. Click the image above to get a better look at the ink tests.

This batch of inks was given a UV light fast test in our sunniest window from March 7, 2021, to June 7, 2021. We also tested the pH levels of the inks to see just how neutral they are. The following is all raw data that we thought you might find interesting. As we do not know the chemical composition of each ink or ink sac/converter it might go into, a pH neutral ink does not guarantee it won’t have a bad chemical reaction inside your pen. We have a professional pH tester, which we calibrated just before testing these inks. As a quick chemistry refresher, a pH of 7 is neutral like distilled water. The closer you get to 0, the more acidic the ink is. The closer you get to 14, the more alkali/base the ink is.

Surprises are the most enjoyable parts of these tests. Blues remain entirely unpredictable. One of my all-time favorite blues is Parker Penman Sapphire. Instead of fading out like most blues, it turned purple! Visconti blue fades out when thinly applied, but the thicker lines create a majestic blue-black that is even prettier than the original blue. Colorverse Quasar turned from a rich blue to a light red-purple. Omas blue did what most blues do and faded heavily. Acidity didn’t seem to effect which brands faded and didn’t. Omas was the most acidic blue at 2.3, and Colorverse was the most neutral at 7.9. Both underwent dramatic changes.

There were subtle changes in some of the inks. Visconti’s black turned a dark brown in the sunlight.

Purples fared poorly. Visconti Purple turned a pale pink. Vintage 1960s’ Waterman’s Violet almost completely disappeared. Pelikan Violet held on kinda, turning a deep reddish pink.

Waterman’s Red and Omas’ Red/Burgundy held up best. Neither seemed very effected by the sun. Also interesting was that Omas’ ink was also almost pH neutral at 7.2. We are often warned red can be the most dangerous color to put in a fountain pen. If it is pH neutral, I wonder what chemical reactions happen when it is inside a pen.

We had never previously heard of Francesco Rubinato inks before, but we loved the “Verde” green ink that was somewhere between “Shamrock Shake” and “Kelly Green.” Unfortunately, it turns into a bile-like yellow green with UV exposure.

An OLD bottle of Rotring Red was a very curious color. It was more of a brick red with a hint of orange. Was that because it was already discolored and UV exposed or was Rotring red really like that? Either way, UV didn’t effect the dry ink on the page.

The only color not yet mentioned is the Francesco Rubinato Oro (gold). This is a goupy, heavily sedimented ink filled with gold-glitter. We DO NOT recommend it for fountain pens. It is ONLY GOOD for DIP PENS. Anyhow, UV light didn’t effect it at all, and because we didn’t want to ruin our pH tester, we didn’t check its pH level, either.

Here is the table of our pH results:

Visconti Black…………………………..4.2
Visconti Blue……………………………3.9
Visconti Purple…………………………3.2
Parker Penman Sapphire…………..5.3
Francesco Rubinato Verde…………4.1
Omas Red/Burg………………………..7.2
Omas Blue……………………………….2.3
Rotring Brick Red…………………….8.5
Waterman (1960s) Violet………….3.9
Waterman Red………………………..5.9
Colorverse Quasar…………………….7.9

Levenger’s Ink Kicks Ass!

Mathematical and computer genius Alan Turing famously said, “Sometimes it is the people who no one imagines anything of who do the things no one can imagine.” In addition to being one of my all-time favorite quotes about people, it seems to apply to the world of fountain pen inks, too.

Here is a side-by-side comparison of Levenger’s ink left in the sun for 3 months and the proof sample saved in the dark.

Ink collectors today understandably go ga-ga for Iroshizuku, Diamine, ColorVerse, J. Herbin, Noodlers and many other brands. Yet, often overlooked, is Levenger’s Ink. In many respects, Levenger’s kicked off the ink-color craze a decade or two before our current manufacturers and spectrum were readily available. Levenger’s has had scores of inks of every hue available since some time in the 1990s. Better yet, they are far more affordable than the competition.

Nevertheless, I kinda blew them off…until I stumbled into a large collection for sale. When Dawn and I started testing them for UV light fastness and pH balance, we were blown away.

We started testing 17 colors in March. From March 7, 2021, through June 7, 2021, we hung these samples in the sunniest window of our house. Afterward, we tested the ink still in the bottles with a pH meter calibrated to 21ºC.

Here is a side-by-side image of Levenger’s inks left in the sun for 3 months and the sample proof left in the dark.

Without a doubt, these are the most consistently light-fast inks we have tested to date. Even the worst-hit inks were still very close to their original colors. Blue Bahama likely lost the most vibrancy, but it is still easily read and distinguished. Cardinal Red faded to a rich pink, but it is still quite legible. Raven Black, Gemstone Green and Greystoke got DARKER in the sun!

Given the great results from the light-fast testing, we feared the worst with the pH tests. BUT! We were only further dazzled. Many of the inks were very close to neutral, and none of the inks veered off the spectrum of acidic or alkali.

As a basic chemistry refresher, 7 in a pH test is neutral. Distilled water is 7. The closer to 0 you go, the more acidic something is. In the opposite direction going up to 14 is more base or alkali. In theory, you don’t want an acid or a base sitting in your ink sac for too long. Yet, one thing we always like to remind people is that regardless of what the pH result is, we do not know the chemistry of the ink nor how it interacts with your rubber ink sacs, celluloids or converters and the like. Depending on the chemical reaction between the ink and what it is resting in, a neutral ink can do damage and an acidic ink might be safe. The pH measurement is simply a data point we find fascinating, but it doesn’t necessarily indicate which inks are safest for your pens. With that in mind, here are our Levenger pH results:

Ink Color              pH Measurement
True Teal                        7.1
Empyrean                      6.8
Blue Bahama                 6.6
Skies of Blue                 7.3
Cobalt Blue                   8.0
Regal                             7.2
Amethyst                      8.4
Raven Black                 8.3
Claret                            8.7
Pomegranate               8.3
Shiraz                           8.7
Cardinal Red               6.8
Blazing Sunset            6.7
Cocoa                           7.3
Forest                           7.1
Gemstone Green        7.2
Greystoke                    7.4

As always, I hope you find this information to be interesting and enjoyable.

Diamine Versus the Sun & a pH Test

People often ask what my favorite ink brand is, and, more-and-more it is Diamine. Just like the Beatles, Diamine is based out of Liverpool in the United Kingdom. However, they beat the Beatles to the scene by 100 years in 1864.

In all of my experience with the ink, so far, it has been very fountain pen friendly. I’ve had great success with it in modern and vintage pens, plus, it has a zillion different colors for sale. The only things I don’t mess with are their shimmer inks because shimmer inks clog the daylights out of pens.

Diamine blue inks generally hold up pretty well to the sun’s harsh rays. It is a rare feat among blue inks.

When I stumbled into 14 different ink bottles from a collection I knew it was time to do one of our famous inkfast tests and pH tests.

The results are interesting. Although they lose a bit of their luster, most of the blues are pretty tough and don’t let the sun and UV light bully them. Silver Fox barely fades at all. When still fresh looking, three of my favorite blues in production are Diamine’s “Majestic Blue,” “Blue/Black” and “Blue Velvet.” The only blue to really fade much was “Presidential Blue.”


Ancient Copper holds its beauty better than most colors, and it is almost pH neutral!

Breaking into some of the more colorful Diamine inks, the sun proves more aggressive. “Ancient Copper” holds up amazingly well, but  “Red Dragon” takes a hit. “Amazing Amethyst” really takes it  hard and almost completely fades out. The very popular “Oxblood” fairs well, but it still fades a bit.

The pH testing surprised us. As a quick reminder, in the world of pH testing a 0 is extremely acidic, 7 is neutral and 14 is extremely alkali or base. We calibrated the testing device and tested the inks at 24ºC.

Diamine Ink Name              pH  Test  Result
Ancient Copper                                   6.7
Red Dragon                                        2.5
Oxblood                                              2.5
Amazing Amethyst                             6.1
Sherwood Green                                4.4
Blue/Black                                          4.1
Oxford Blue                                        3.8
Presidential Blue                                3.2
Majestic Blue                                     4.2
1864 Blue/Black                                4.5
Silver Fox                                          4.0

Before you throw out any ink you might love, please keep in mind that the pH is only a data point. We don’t know what chemicals are in each ink, and we don’t know how their chemical properties will react to your ink sacs or converters. We’ve seen acidic inks used safely in ink sacs for years and neutral inks destroy ink sacs in a matter of months.

That said, we’ve always had great success with Ancient Copper, which is one of our personal favorite ink colors.

We hope this information is interesting to you…and maybe even help you.