Pilot Iroshizuku Konpeki is a well loved and popular ink which you probably have heard of already if you are in the pen community. Here are my two cents.
First off it is important to say that this line of ink is an expensive one. You get 50ml in a gorgeous bottle and packaging from $25 if you manage to find a deal, to $35. That being said, I would recommend picking up a bottle in a colour that strikes your fancy if you can afford it, as the ink is of great quality, behaves wonderfully and there are some unique colours in the line.
As you can see in the pictures, the ink is nice vibrant blue. It has enough vibrancy that it pops of the page but it is dark enough that it could be used for large amounts of writing. Depending on the wetness of the pen you are using, the ink can come off quite dark or lighter.
The ink also shades beautifully, despite being relatively saturated. It is possible to get some sheen but it only comes out in really wet broad pens and you won’t typically see it in a medium or finer. I wrote that there was no shading but that was before I did some really wet swatches and used it in really wet pens. The red sheen is quite nice, just don’t expect it to be there all the time.
The ink performs wonderfully in a variety of pens and is a pleasure to use. I never encountered any flow issues and I have used it in many pens. I personally preferred it in slightly wetter pens because the colour was darker and richer. You can see in the pictures that the ink got quite light in colour in my Lamy vista which has a very dry nib. Compare that to the writing below with the Pilot Custom Heritage 91 and you can see the variety you could get with this ink.
Iroshizuku inks are generally well behaved and Konpeki is no exception. There is no feathering and bleed-through on cheap paper except with the wettest and cheapest paper. Sometimes a bit of show-through but not usually on good paper like Rhodia. The reason why there is slight ghosting in the picture above is because I used a pilot parallel that was freshly inked. With drier pens there is no show-through. The ink also dried fairly quickly and shouldn’t be a problem for lefties. My brother is a lefty and he uses the ink with no problems.
What surprised me about the ink was its slight water resistance. Iroshizuku inks don’t typically have very much water resistance so I was expecting it to melt off right away after coming in contact with water. Granted, there is still a lot of ink coming off the page but there is enough remaining on the page that your work could be copied and transferred.
Ink Colour Comparisons
Out of my small ink collection, Diamine Asa Blue is the most similar and comes very close to Konpeki. The bottom swatch is significantly darker because i had just inked up my pilot parallel. The swatch above it is a better indication of the colour. I have a full comparison of the two inks in my blog post Diamine Asa Blue vs Pilot Iroshizuku Konpeki.
When I was using the Uniball eye rollerball I thought that the colour was very similar, but upon closer comparison it appears that it is darker.
Overall this ink is a winner. Gorgeous colour and great performance to match. If it’s within your budget and you were looking for a nice vibrant blue, I’d say give it a try.