HP 6657/6658/8728 Refill Instruction
1. Peal off the top label. You can see there are 5 holes
(#57 and 28: two for Yellow chamber, one for Magenta chamber, and two for Cyan chamber;
#58: two for photo Black chamber, one for photo Magenta chamber, and two for photo Cyan chamber).
2. Place the printhead on several layers of paper towels to absorb any excess ink while refilling.
3. Fill the syringe with ink and very slowly inject up to 5 ml.
for each color (3 ml. for #28) into correct hole until the color just begins to show in the white sponge.
4. Put the label back with scotch tape or leave it off.
5. Set the cartridge in little container for 5 minutes as a drip precaution.
Clean the printhead with a paper towel. Make sure no dripping, then install the cartridge to make a test print.
6. Clean the syringe with water and dry for future use.
* Suggest refilling sequence Yellow > Magenta > Cyan.
Clean the syringe with water and shake several times to let residual water out before different color refilling.
* Refill immediately once cartridge is empty.