Digital BW, The Print

I was wondering if anyone had experimented with mixing Claria C, M and Y outside of the printer to make a neutral(ish) grey ink. I was thinkig of using the Claria K, the mixed grey and a diluted grey to make a BW inkset. I know poeple have experimented with diluting the Claria K and reported fading problems. From what I can piece together the K is only really stable in the long(ish) term when it is at maximum density. The Epson drivers certainly seem to only use it at high densities. But it seems that the colour inks aren9;t affected by this weaknes. But I have no idea what the effect of mixing these inks together might be in terms of ink stability in the carts/bottle or print stability. Or in any other terms. Does anyone have any information or experience mixing such a grey ink and diluting it?

Thank you everyone for all the information.

Thank you Paul for sharing your experience. This is exactly what I was asking about and I appreciate you providing me with a search term, 'catalytic fade', to get me started learning some more. I respect your opinion in these matters and even though you are careful to establish that your conclusion may not be founded, I regard even your suspicion as significant.

Thank you, Ernst and tboleyyh, for your feedback regarding colour artefacts when mixing coloured inks to make BW prints. I was really asking about the problems that might occur when mixing inks outside the printer, which largely remain an unknown. But, of course, I am very interested and appreciative of your feedback regarding the use of colour inks for BW printing. In regard to metameric failure and achieving a neutral (enough) print tone, these are things I can experiment with, even with the inks in the default configuration. Paul has suggested that as little as one third K load is sufficient to minimise the colour artefacts for a range of lighting conditions. I find a pretty large range of tones attractive so maybe I can trade 'neutral' for an easier 'pretty'. When I have a functioning printer working again I look forward to experimenting. Perhaps I will end up just using the K in the end.

As for the unknown fade properties of the various colourants that will cause the tone of the print to change over time, Aardenburg fade test results might give some clues. They seem to indicate that while grey patches printed by mixing the coloured inks fade toward blue, those printed using just the K tend toward brown relatively quickly (although by Aardenburg's Conservation Display ratings the K ink alone still scores better). Maybe the two could compliment one another. The best choice, by far, seems to be a good lacquer though.

Paul, you have mentioned in the past that the diluted K exhibited poor fade resistance. Out of curiosity, can I ask if this was significantly worse than a print using just undiluted K (allowing for some neutralising colour)?

Thanks again. If I find the time I'll post with my own experiences, but I probably won't mix a grey outside of the printer until I hear of somebody who has had great success trying it first.