Tuesday, 24 June 2008

procion dye shelf life

Procion MX one year shelf life? Tosh! Who started this myth? I've tested it using 18 month old magenta (red MX-8B), yellow (lemon yellow MX-8G) and black (Kenactive black K2647) and 11 month old cyan (turquoise MX-G) - all acquired at the same time (I think). They looked fine after painting, but once boiled the cyan obviously didn't fix well, as shown in the first photo. (I made the colour wheel ten or more years ago - the centre has 100% strength primary and secondary colours, with tertiaries also showing in the outer ring. The two in-between rings are primary and secondary colours at different dilutions).

I wasn't convinced by the depth of the test's black either, but serious-black always has been an issue with Procions.

Tucked away on the studio dye shelf were several pots of older dye, some even dating back to 2004 (first opened date), and some unopened pots. I was surprised to have such a collection - usually I only look when ordering new dye. There's also a stack of empty pots. Well-meaning I've intended to send them back to the supplier for re-use but haven't yet taken the final necessary step. Perhaps I should make this a little job for this week. Luckily I had an unopened cyan (though different supplier) and black (and magenta).

I ran a further test, as shown in the second photo where the year of first opening a pot is also shown. Even when painting the cyans the 2007 pot could be seen to be lighter than the 2005 and 2008 pots. To ensure it wasn't a mixing error on my part I made up a further pot of 2007 cyan, shown above the magenta where it (erroneously) says 2008 - I decided against opening a new magenta as the 2006 colour was fine.

A surprise was to find the 2006 black I was previously unsure of now looking better/darker than the old 2005 and newly opened 2008 batch. The 2003 magenta looks as good as the 2006 one, and all lemon yellows (2004, 2005, 2006) looked equally good - though as demonstrated in the colour wheel differences in tone of yellow aren't easy to grasp. For many years I have mixed lemon yellow (and advised students similarly) at a slightly higher concentration than other colours, because it seemed to need it. Perhaps I once had a 'dodgy' yellow and needed to then but this test shows there's no need to. Well that's good for resources and pocket!

To sum up, three dyes opened 18 months ago (at time of purchase) have lasted longer than one opened within the last year (also bought 18 months ago). Another dye just opened (purchased in last year?) is also inferior to that opened 18 months ago. Dyes can fix quite adequately even at five years old.

How to ensure newly purchased dye will be of a higher or equal quality to that 'past its shelf life'? I just don't know. You rely on being supplied with fresh stuff; suppliers aren't likely to tell you if it isn't.

Over the years I've bought Procion MX from three British suppliers. I used to buy cheaper dyes from one just for workshop use (when I was running lots of workshops), but wouldn't use them in my own work because the colour intensity wasn't as good. I shrugged that off as inevitable considering price difference (the 2008-opened cyan and 2005-opened yellow are these dyes, and yes I think the 2008 cyan is marginally lighter than the 2005, but not as pale as the 2007).

Maybe it all began changing when ICI's patent on MX dye ran out and anyone could then manufacture them. One company has been more open than others saying their MX is manufactured in Indonesia and naming the company.

For sure Procion does have a shelf life, though. I found out the hard way in my early years of batikking. It was a commission for a magazine front cover, with the possibility of the next two issues too. I was chuffed, flattered and very scared to have such a prestigious (and well-paid!) job to do. Very close to the deadline I went to boil out the wax - and one major colour bled bled bled! All the impact of colour A against colour B was lost - the design balance skewed and it just didn't buzz any more. There was no time to re-do it, I was too tired and wouldn't have had the subtlety for fine canting work at that eleventh hour. Devastated and despondent I had to explain what had happened. As expected they decided not to go with it despite me asking them to adjust the colours digitally back to how they were originally (at that time I had no computer and no idea whether it could be done). I felt so unprofessional... But a happier ending - some months later they came back to me - they'd decided they liked the design and would attempt colour correction. It was published but the colours they came out with were different from mine.

So... the conclusion on Procion MX dye shelf life is: demand suppliers state how old the dyes are when you buy them. Write not just the date of opening on the pot but also the date of purchase and manufacture. Test them immediately - if they are weaker than the 'old' dyes, hmmm... Don't want to fall out with the suppliers, but really I think they would need to give an explanation.

Of course, if I become a 100% woad dyer, I won't have this problem. Or rather, I very probably will but it's different as variations in woad colour will be as much down to nature and the annual crop - not wholly the grower's responsibility. Synthetic dyes are meant to be consistent.

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