About Canon BCI-3eBK & PGI-5 Inks.
Information related to pigmented-waterproof ink and dye based ink.
This article is not designed to promote either type of ink. This article was written to specify the types
originally found in Canon brand name cartridges as well as many aftermarket cartridges and refill kits.

CANON BCI-3eBK.
Here's a little primer for those who are not aware of the differences in Canon original BCI-3eBK ink cartridges, many aftermarket ink jet cartridges (generic, third party, aftermarket) and/or refill kits and bulk inks for the BCI-3eBK.

Canon original, brand name BCI-3eBK ink jet cartridges use a pigmented - waterproof black ink. This ink is ideal for business documents or documents that require a long lasting waterproof ink. If you are printing legal documents, tax documents and alike it is strongly recommended you use a pigmented - waterproof black ink.
In many Canon printers (5-color to be specific) you'll notice that Canon uses two cartridges for black. The BCI-3eBK which is pigmented - waterproof and a BCI-6BK which is a dye based.

The BCI-3eBK is not used when printing photos. This is because the dye based colors in these printers does not mix well with the BCI-3eBK pigmented black. The use of the BCI-6BK in the printer is to increase the color gamut and print better photos as the dye ink in the BCI-6BK is the same type of ink as the colors.
If you run a four color Canon printer using the BCI-3eBK you'll probably notice that some black text does not quite appear completely black. This usually occurs when printing a photo that contains black text or printing black text in photo mode. The reason the four color printers using BCI-3eBK have this issue is that the three colors, cyan, magenta and yellow are used to create the black. You generally see a muddy or even green tinted color when printing using this composite black.

Most aftermarket, third party, generic cartridges on the market today for BCI-3eBK use a dye based alternative to the pigmented ink. The common reason for this is that dye based ink is cheaper then pigmented ink. There is no debate that consumers commonly choose ink based on price. To be competitive many aftermarket companies chose to use dye based ink. Though the ink is a fully compatible ink it is not pigmented - waterproof ink. Some companies today do offer pigmented black pre-filled ink jet cartridges. It is common for these companies to promote that fact.

To keep costs down and in keeping with the aftermarket cartridges many aftermarket refill kits also contain dye based ink for use with the BCI-3eBK ink jet cartridges. Not all aftermarket ink jet refill kits and bulk ink sets contain dye based ink though. As a general rule of thumb aftermarket companies selling the more expensive pigmented - waterproof ink will promote that fact.

When choosing an ink to replace your BCI-3eBK ink jet cartridge you should consider your needs.
If you are in need of a pigmented - waterproof black ink consistent with the Canon BCI-3eBK then you should make sure the inkjet cartridge, refill kit or bulk ink contains the pigmented - waterproof black ink. As stated above most companies will promote this.
If your your needs are based solely on price then dye based ink should work just fine for you.

Additional information: After writing this article for my website I began to receive emails regarding four colors printers. The common question asked was: "If I use a dye based ink for my BCI-3eBK four color printer won't the printer print better photos as all of the ink is now the same type of ink"
The answer is no, as your printer does not know the ink is dye based. The printer's built in firmware is designed based on the black being pigmented - waterproof. The use of a dye based black does not change the way the printer "thinks".

CANON PGI-5
Here's a little primer for those who are not aware of the differences in Canon Original PGI-5 ink cartridges, many aftermarket ink jet cartridges (generic, third party, aftermarket) and/or refill kits and bulk inks for the PGI-5.

Canon original, brand name PGI-5 ink jet cartridges use a pigmented - waterproof black ink. This ink is ideal for business documents or documents that require a long lasting waterproof ink. If you are printing legal documents, tax documents and alike it is strongly recommended you use a pigmented - waterproof black ink.
In many Canon printers (5-color to be specific) you'll notice that Canon uses two cartridges for black. PGI-5 which is pigmented - waterproof and a CLI-8BK which is a dye based.

The PGI-5 is not used when printing photos. This is because the dye based colors in these printers does not mix well with the PGI-5 pigmented black. The use of the CLI-8BK in the printer is to increase the color gamut and print better photos as the dye ink in the CLI-8BK is the same type of ink as the colors.
If you run a four color Canon printer using the PGI-5 you'll probably notice that some black text does not quite appear completely black. This usually occurs when printing a photo that contains black text or printing black text in photo mode. The reason the four color printers using PGI-5 have this issue is that the three colors, cyan, magenta and yellow are used to create the black. You generally see a muddy or even green tinted color when printing using this composite black.

Most aftermarket, third party, generic cartridges on the market today for PGI-5 use a dye based alternative to the pigmented ink. The common reason for this is that dye based ink is cheaper then pigmented ink. There is no debate that consumers commonly choose ink based on price. To be competitive many aftermarket companies chose to use dye based ink. Though the ink is a fully compatible ink it is not pigmented - waterproof ink. Some companies today do offer pigmented black pre-filled ink jet cartridges. It is common for these companies to promote that fact.

To keep costs down and in keeping with the aftermarket cartridges many aftermarket refill kits also contain dye based ink for use with the BCI-3eBK ink jet cartridges. Not all aftermarket ink jet refill kits and bulk ink sets contain dye based ink though. As a general rule of thumb aftermarket companies selling the more expensive pigmented - waterproof ink will promote that fact.

When choosing an ink to replace your PGI-5 ink jet cartridge you should consider your needs.
If you are in need of a pigmented - waterproof black ink consistent with the PGI-5 then you should make sure the inkjet cartridge, refill kit or bulk ink contains the pigmented - waterproof black ink consistent with the original cartridge. As stated above most companies will promote this.
If your your needs are based solely on price then dye based ink should work just fine for you.

Note: By switching to a dye based ink in the PGI-5, on a four color printer you will not achieve a better color gamut or better black text in photo modes. Your printer is designed with firmware that is preset to use the PGI-5 in a specific manner. So changing the ink does not affect the way the printer "thinks".

IMPORTANT NOTES:
Once again, this article is not designed to specifically promote the use of a dye based or pigmented ink as a general rule of thumb.