Liquidraw Technical Pen Waterproof Drawing Ink Black 25ml (Compatible with Rotring Isograph Pens) NK100 - BL

I used this to refill my Reform Refograph 0.35, a pen I have used for over 30 years. The ink runs smoothly and dries quickly, which is the most important fact. The bottle requires a little patience to open but I don't think this is because it is poor quality but because it is good quality. Here are my tips, which result in no spill or mess at all. Once you screw off the black cap and then lift off (not screw off) the clear plastic nozel cap you will find that the nozzle is solid down to the ink level. I found what works is to take a thin nail (which has a pointed end) - the bronze looking type you lightly tap in the wall to put up picture frames and just lightly tap it down into the nozzle. If you do this gently the nail will eventually pierce through to the ink effortlessly. Then you gently lift the nail out, wash the nail and put the clear nozel cap back on and screw back on the black cap. The nozel will now work perfectly and you will have a nice clean small hole into the bottle through the nozel, which will help avoid clogs. If you use a paper clip (which has a flat head), you will quickly find it difficult and then you will start applying too much pressure and then pop all the ink will spray out and you will be left with a mess and a screwed up nozzle. Hope this helps. Small bronze nail, gently tap tap in with hammer into the nozzle and then gently remove.

Comes with a needle -- no problem opening at all. Otherwise performs like any other standart technical pen ink. Waterproof.

A pain in the rear to open and get the ink out without getting ink all over your hands and then to discover that the ink has blocked my pen. May be suitable for other pens but not my rotring.

A good quality product. The bottle was very well sealed for transportation.It was a bit fiddly to open . I would prefer it to come with a small Inkwell.

I bought this to use in my Rotring Isograph 0.1 and it works perfectly fine without any issues. The filling itself might be a little fiddly but if you're patient and take your time it all works well without mess. Ink flow is fine, the line is crisp and dark and I'm very happy with it. I draw a lot with it, it doesn't take long to try, under 30 seconds on plain paper. I haven't experienced any clogging issues since washing out the pen thoroughly before filling. And it refills fine without having to wash again. If you leave it unused for a few weeks though, or a month, the pen may clog up and need to be washed out.

Much cheaper than Rotring original - on which it is clearly copied from. Worked fine in an Isograph without any clogging. About as waterproof as the Rotring original - that is too say don't push it too far.

Great flow and black is black and not purple like some Blacks are

I have no idea yet about the ink itself, but the rigmarole for opening the bottle is ridiculous.Other reviewers have sensibly suggested pushing a suitably thin nail down the nozzle. That was fine, except that the nail then needed to be removed - and, surprise, surprise - the nozzle actually turns out to be detachable (something I had attempted unsuccessfully to make happen at an earlier stage).I am quite sure it cannot really be necessary to insert a nail in order to remove the nozzle unit, but that seems to be the route to success. Quite barmy (imho).UPDATE: I have since received a bottle of ink of a different colour. This time, the box also contained a needle with a grippable head. Problem solved (when one is fortunate enough to receive the pin!)