In case filling color cartridges (1823/6578) you should make allowance for this, that needle must be close to protective reticule. The needles sold in drugstores are unfortunately too short. We propose needles with 12 cm length, what is definitely enough to apply ink very close to protective reticule (that is almost near the nozzles) . It is basic condition of right filling cartridge.

Attention !!!
In case filling the middle chamber (Magenta) we have to apply the needle with special caution, because we can damage reticule, which is situated a little bit higher than in other chambers and also perpendicularly to applied needle.
In other chambers (Cyan, Yellow) you can apply the needle until you feel resistance.