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  4. CLI-42Y (Yellow) Cartridge – Special Considerations

CLI-42Y (Yellow) Cartridge – Special Considerations

Update #2: August 31st 2017

The question of the Yellow Jello issue is one that has been around now for years now and while we still believe that our inks are not affected there have been an incredibly small number of reports which indicate that the original CLI-42Y does appear to have some impact on the use of the original CLI-42Y cartridge.

Rather than ignore the potential for problems we have adopted and now supply a work-around that avoids the issue completely.

All refill bundles and any orders for CLI-42Y empty cartridges are automatically supplied with a CLI-8Y as a surrogate which can (once chips are swapped) be used as a replacement for the CLI-42Y and refilled without needing to worry about potential yellow jello or similar issues.

Any customers who have purchased a Pro-100 refill bundle or empty CLI-42Y cartridge (or set containing same) that have not already received a CLI-8Y with their order can contact us with their order reference and we will forward a CLI-8Y cartridge (free of charge).


Update #1:

This article was originally written in response to concerns and issues relating to a competing product. To be absolutely clear we have since confirmed that there is no problem using the inks supplied by OctoInkjet. They will not combine badly, do not cause undue clogging or otherwise cause damage to your Pro-100 printer beyond the normal hazzards of refilling.

Further to that, we’ve created a guide for flushing/refreshing cartridges (including the yellow) using our refill ink rather than water or any cleaning solution. You can find the guide here.

Original Article:

This article is applicable to the Canon Pro-100 printer and in particular to flushing and refilling of the OEM/Original Canon CLI-42Y (Yellow) cartridge.

Key Information:

  • OctoInkjet inks do not cause an adverse reaction to the original ink in Canon CLI-42Y (Yellow) or any other CLI-42 cartridge.
  • CLI-42Y (Yellow) cartridges should NOT be flushed as water will react and eventually cause clogging.
  • No other CLI-42 cartridges are affected.


Background/Detailed Information


It has been observed that the use of water to flush a CLI-42Y cartridge does encourage a jelly like substance to form in the cartridge. As a result should be avoided.

If a CLI-42Y (Yellow) cartridge requires flushing it should be carried out with a compatible flushing solution (to be determined) or preferably the cartridge should be replaced with either of the following:

  • a flushed CLI-8 yellow cartridge
  • a new CLI-42Y cartridge that does not need to be flushed


  • Original/OEM CLI-42Y cartridge (Yellow)
  • Refilled with third party ink supplied by Precision Colors (and potentially other suppliers)
  • Flushed/Filled with water

Description of Problem:

The Canon original CLI-42 yellow ink appears to combine poorly with a specific third party ink supplied by Precision Colors, in a way that forms a gel like substance capable of blocking the inlets for the printhead and causing a clog and damage to the printhead.

The original ink appears to contain a component that forms a gel like solid when insufficient amounts of original ink remain in the cartridge. As a result the problem is rarely immediately noticeable except possibly when the cartridge has been flushed with water prior to use.


  1. Use inks supplied by OctoInkjet (they do not cause the same issue)
  2. Use a CLI-8 cartridge (preferably Yellow) as a replacement. These cartridges are physically identical but do require a chip swap to use the CLI-42 type.

Process (2):

To use an alternative cartridge:

  1. We recommend it be completely flushed of any previous ink (if applicable)
  2. Remove the original chip from your replacement cartridge and replace with the CLI-42Y chip
  3. Refill using your preferred refill method as normal
  4. Install the replacement cartridge and run a full cleaning cycle and nozzle check immediately
Updated on 9 February 2022

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