water - carbon cost

While working out my carbon footprint earlier this month I also mentioned my annual water consumption, and started pondering the carbon cost of water. I emailed South West Water, the water company for Cornwall and Devon, and fairly soon after received a reply from their Carbon Manager David Rose (impressive they have a dedicated Carbon Manager but apparently many similar companies do now).

Clean water delivered: 173 grams CO2e per cubic metre of water delivered to your tap.
Waste water returned: 870 grams CO2e per cubic metre of waste water returned to sewer.

(CO2e = carbon dioxide equivalent)

This equates to 1043 grams CO2e per 1000 litres for combined clean and waste water supply - I have to admit to surprise for the low delivery figure for fresh water. But then, water arrives freely from the skies. It doesn't (here anyway) need to be pumped up from the ground.

If there is a message to be read from these figures it's that the less 'contaminants' we put into the waste/sewer the lower their clean-up costs, and this might help lower emissions. David explained that the waste figure includes methane and nitrous oxide emissions from the recycling of waste water sludge to land. Or muck spreading as I've always known it.

My household carbon contribution from water use then is:

34,527 litres
= 34.527 cubic metres x 1043 grams
= 36011.661 grams CO2e
= 36 kg CO2e pa

Thirty-six kilograms, or 0.036 tonnes, sounds not very much in comparison to other emission costs, such as heating water or travel. So it seems best to retain focus on reducing quantity of water due to its eminent predicted global shortage.

So, over the next year I should aim to reduce consumption, and consider what gets disposed down the mains that needn't and other options for disposing of it (or do away with it altogether?).



Emission levels from all UK water companies are shown in Figure 4 on page 12 in Water UK's Sustainability Indicators 2007-08 Report.

United Utilities have a user friendly (figure-phobic) water use/carbon calculator here but be aware the final figure includes not just the carbon cost of water supplied/taken away but the carbon cost of heating it.


Update 14 February 2009
South West Water have announced plans to trial a rising block tariff. There will be three blocks, the first low rate 'essential use', the second standard rate 'safety net' and third premium 'non-essential use', with the first block charged at 27% less than the standard rate.

For a one person household the essential band is 1-8 cubic metres/quarter, the standard 9-13, and premium 14 and over. So I'm thrilled to see that my existing quarterly use only just flips over the essential use level!

2008 carbon footprint

8.57 tonnes CO2 - CarbonFootprint.com
7.60 tonnes CO2 - Resurgence
5.49 tonnes CO2 - Energy Saving Trust
5.27 tonnes CO2 - ActOnCO2 (UK government's)


Back in June 2007 I wrote about my carbon footprint, as worked out on a range of calculators. Last summer I intended to re-measure and compare, but felt such an activity was better suited to dark and cold winter evenings. So my new footprint is for the calendar year - January to December 2008.

Depending on calculator used the carbon footprint ranges from 5.27 to 8.57 tonnes of carbon dioxide. Resurgence and CarbonFootprint.com's calculators endeavour to include lifestyle and industrial share as well as the energy and travel factors. When taking energy and travel alone these footprints fall into the same range as the other two, at 5.1 and 5.57 tonnes.

Two major changes from last time are using the car and having double/secondary glazing fitted. It's been interesting to see what changes they have brought.


Travel

2.46 tonnes CO2 - Resurgence
2.29 tonnes CO2 - CarbonFootprint.com
2.01 tonnes CO2 - Energy Saving Trust
1.99 tonnes CO2 - ActOnCO2

Last year my footprint was 6.3 to 7.5 tonnes CO2 annually depending on the calculator used. But when my average driving mileage of 10,000 miles pa was factored in it rose to around 9.5 tonnes!

So one plan for 2008 was to restrict mileage to 6000 pa, roughly 500 miles a month or a tankful of fuel each month. Five hundred miles sounds a lot and is a lot and in general wasn't too hard to stick to. But two long-distance trips – to Norfolk in the spring and recently to visit family in Shropshire - were all it took to push me over by 831 miles. So I failed. Or failed to stay below my target, but I did learn that lower mileage is achievable. Several times I told others or myself I couldn't afford (meaning 'spare') the petrol that month, or consciously decided I didn't really need to go/do where/whatever. Some people seemed incredulous that I was rationing my fuel use... until fuel prices went over the pound/litre rate mid summer. All future long distance travel must be managed better. Or differently. I will have to think about this.

I also have attempted being a better driver – maxing at 60 mph on dual carriageways and slower on main roads. I've tried smoother gear changes and check the car tyres monthly. I keep records of mileage done when filling the tank. All the stuff they bang on at us to do.

My 2008 travel footprint ranged between 1.99 and 2.46 tonnes for the 6831 miles. Because it's an older car (R reg), each calculation was based on a generic 1.4 litre petrol car. However the smttCO2 website calculates emissions from every model and age of car. My Peugeot 306 hatchback emits 176g CO2 per kilometre and so, for my mileage, 1.93 tonnes for the year – less but in the same range as the calculators. Probably they also incorporate factors like oil changes and service materials - fair enough.

Two years ago I signed up to TargetNeutral, a carbon offsetting project initiated by BP. I was and am sceptical about the merits and morals of offsetting carbon but then as now feel that showing willing and concern is the important point (to oil companies and politicians!). Hence, despite having paid around ten quid to 'offset' my 2+ tonnes of CO2 (shockingly cheap, carbon, innit!) I am not subtracting 2+ tonnes from my footprint. Why not? Because although TargetNeutral purchases carbon credits from projects that sound worthwhile I have no idea if their carbon figures are also being used elsewhere, ie multiple accounting.

For instance, if a wind farm was installed here in Cornwall thus removing x tonnes of CO2 pa and TargetNeutral bought these emission reductions as carbon credits, that's one thing. But should, for example, the local authorities then be able to incorporate these reductions into Cornwall's renewable energy figures? In some ways, yes, but not when an overall (eg national) picture of emissions reduction is wanted as the figure could be counted twice. Unless I've missed something! So, for now, I'll continue offsetting but not including the figure in my own footprint. The most viable current option to reduce carbon remains to reduce mileage not buy your way out.

(A few catches about TargetNeutral – you have to buy BP fuel and use a Nectar loyalty card (so your purchases are logged). And then go online once a year to confirm details and pay up. BP fuel seems to cost a little more than elsewhere but that's fine as I seem to get more mileage per tank on it.)


Energy

3.48 tonnes CO2 - Energy Saving Trust (of which 3.22 heat/0.26 appliances)
3.28 tonnes CO2 - ActOnCO2 (of which 3.06 heat/0.22 appliances)
3.28 tonnes CO2 - CarbonFootprint.com
2.63 tonnes CO2 - Resurgence

I've spent an hour getting my head around the variation in these energy footprints from different calculators. Surely all should be the same, considering the same 6113 kwh annual figure was used? Resurgence uses a conversion figure of 0.43, same as I used last time and understood to be the industry standard conversion figure.

But on a National Energy Foundation page it says that 0.537 should be used when calculating carbon footprints and is "based on a 5 year rolling average UK electricity generation mix of coal, nuclear and gas turbines, as well as renewables". And, no surprise here, 0.537 x 6113 kwh = 3.28 tonnes CO2. (Why EST's is a bit higher can remain a mystery for now! Either they add some for energy loss during transmission (sensibly) or they hadn't updated their rolling 5 year figure.)

The lower figure of 0.43 apparently is appropriate if estimating "emissions in line with Climate Change Agreements (CCAs)... or when estimating energy savings". This lower figure is "based on marginal emissions (which are usually those from high efficiency Combined Cycle Gas Turbines)". Aaah. I see. Sort of.

I thought that when I last calculated my footprint, 0.43 was seen as the conversion figure representing the average UK mix of electricity generation. But in 2008, according to ElectricityInfo.org, the average UK mix comprised coal 33%, natural gas 43.5%, nuclear 16.1%, renewables 5.5% and other 1.9% with CO2 emissions at 0.48 kg/kwh.

Ecotricity's mix includes renewables at 37.4% (up from 26% in 2007), and its CO2 emissions were 0.267 kg/kwh. I think this means I could get away with using a conversion factor of 0.267 for my annual energy use... but won't. The national availability of renewables is limited, at 5.5% (also shockingly low, innit?), and so the national share must be used however irksome it is being forced to use a rolling 5 year figure when one for 2008 is available.

So, my energy related emissions were 3.28-3.48 tonnes of which 3.06-3.22 was from hot water, heating and lighting, and 0.22-0.26 from appliances. Both figures are down from last time (3.48 and 0.38 in 2007, respectively). Quarterly usage to end December also was lower than a year ago. The double and secondary glazing were fitted in late November and early December – it will be fantastic if they are responsible for this small reduction on the heating side!

Appliance related emissions dropped more markedly – this might be because I have made every effort to switch off and unplug everything not in use – though tend to have forgetful phases with the kettle, and very unremembering with the cooker. An old anglepoise lamp also remains plugged in and switched on but that's due to its temperamentality. Otherwise all is off as much as possible. I never would have believed it could make this much difference. But all the official advice suggests doing it, so it was worth trying!


Industrial Share, Lifestyle and Other Extras

3.0 tonnes CarbonFootprint.com
2.5 tonnes Resurgence

Only Resurgence and CarbonFootprint.com's calculators included an industrial and lifestyle section.

Resurgence invites you to analyse your life by, amongst other things, income. It suggests for every £5000 of income you add a tonne of carbon, reducible only if you endeavour to buy second hand, locally made, craftsman made, repair etc. They also allocate everyone a tonne from the national share of common and public amenities. I made my lifestyle emissions 2.5 tonnes last time, and arrived at the same figure this year.

CarbonFootprint.com's worked from lifestyle questions with multiple choice answers. For example it asked whether you 'always', 'sometimes' or 'never' bought organic food. With this question and a few others I found the range of answers limiting – there was no 'mostly' to choose, and 'always' would have been a lie on my part. So after running the test again with 'fully' answers where I needed an alternative, I worked out what I believe to be my truer position – 3.0 rather than 3.14 tonnes.

Both calculations are subjective and only a guide. In time as more goods and services become carbon costed we all will start to know our true lifestyle carbon cost.

How soon will the time come that I can give a carbon cost for a batik? Not this coming year, I expect. But it remains an aim.


Water

The carbon cost of water and water industry related services isn't included in the calculators (though may be incorporated in the lifestyle sections). I haven't found a source online giving a conversion figure but have emailed South West Water to ask them.

Water carries its own cost of course – the planet is running dry from over consumption and waste of fresh water. My household water use for the year to 5 November 2008 was 34,527 litres or 94.59 litres a day. Although year on year it's down nearly 7000 litres, or 9 litres a day, when I think of it as 47 two-litre bottles full of water and lined up every day inside my house I struggle to comprehend how – where - I could be using so much!

But just as with the carbon calculators, there's also water use from lifestyle to consider. WaterFootprint.org have a calculator that gives a per capita average depending on the country you live in. Mine comes out at 694 cubic metres a year... or in litres, 694,000. Scarey! Way, way higher than household use! Their website also has a more detailed water use calculator but I need to weigh my average food intake before I can do that.



Thinking about it all

My footprint has come down since last time – sort of. Last time around I'd had to stop driving for a year, and that made it considerably lower than now. But it is near on impossible to earn a living and 'live' here without a car (mine or a friend's) because of the lack of public transport and distances from certain facilities, including train stations. So until I move, a reality of life is running a car. After 15 years I have given up trying to get the authorities to supply a bus service that extends beyond the few daily shopper buses to the local town (8 miles away), or a cycle path that will take cyclists off the dual carriageway. When I move, accessibility to public transport will feature!

At 5.27 my footprint also remains below the UK national average of 9.96 tonnes but above the government's current target footprint of 4.22 tonnes (ActOnCO2).

Residents of the South-West apparently have slightly lower Ecological footprints than the national average – 5.23 compared to 5.36 global hectares, and citizens of three local cities Plymouth, Truro and Exeter ranked 1st (ie lowest footprint), 9th and 14th respectively out of 60 British cities for their ecological footprint. So regional lifestyle is assisting me. On the personal calculator here my ecological footprint came in at 2.33 global hectares - or rather 23.3 gha (don't understand why ten times higher) but still equivalent to 1.48 planets. Down from last year's 1.9 planets... but still obviously an unsustainable amount of planet.

So, my aims for 2009 are to keep lowering usage. Keep mileage below 6000 pa, and better use of trains and buses for long distance travel. With electrical consumption I'll check what difference the double/secondary glazing has made in three months time, when the coldest of weather has passed, and then consider future options for improvement. I'll also continue measuring energy use of equipment used for batik - this is the ultimate aim of course, to give batik a carbon footprint. Water... I must figure out where those 47 bottles worth are being used!

germination!

A magic moment exists when developing your own photographs and the image starts to appear, in batik when wax resists the dye, and also in indigo dyeing when exposure to air turns the cloth blue. But these thrills come nowhere close to those of nature: yesterday a woad seed germinated. The miracle of life unfolding before my eyes... look at those amazing hairs on the sprout, holding tiny droplets of water.

loose dye update 2

A few weeks ago I uncovered the reason for the loose 'magenta' dye, forever slightly washing out but not seemingly weakening the colour on the fabric. Or rather I didn't uncover it, it was explained to me by Stuart at Kemtex... With Procion MX, small amounts of both 'magenta 'and 'cyan' dyes (but especially magenta) continue to move around the fabric a bit when drying. Thus when re-wetted they will rinse out.

It reminds me of warnings on labels in red clothes in days gone by, to always wash reds separately not with other colours, and of ensuing white pinkiness when the warning hasn't been heeded. I think non-MX Procions are used for clothes-dyeing these days which eliminates pink residues.

I did find cyan ('turquoise' in MX parlance) washed out initially then stopped, then magenta ('brilliant red') took over. At least there's no need to keep testing for errors in my dyeing ways. Although I'm a bit annoyed at the time-wasting, there are benefits in that I've learnt more about MX requirements along the way.

Stuart said there is a cationic fixing agent available on the market (and at Kemtex) which is supposed to address this loose-dye situation. Formerly this was formaldehyde based but due to environmental reasons no longer is (info on formaldehyde here and here). Although it resolved washfastness issues it compromised lightfastness so wasn't that wonderful anyway! The new version isn't formaldehyde, but I don't know what it instead IS.

A couple of websites list similar sounding products, Fineotex in India, and Shanghai Tuebingen, a Chinese subsidiary of German company CHT, who make Rewin.

Rewin ST seems the most promising, mentioning the difficult dyes by name but will give "slight shade changes". Slight changes could be catastrophic if a perfect harmony or balance of colours was intended but was then altered. What is so good with Procions is the brilliance of the colours, that complimentaries (or other pairings) can really sing and vibrate against each other. Take that edge away and the whole appears flat and lifeless. Fineotex NFE is apparently eco-friendly but we have only their word for that (or maybe not even that: "the information is in good faith but without warranty"). It doesn't say if it will affect lightfastness or change colours.

Anyway, as my Procion batiks are generally never re-washed after framing there seems no reason for me to need (read 'risk') this additional fixing solution. Or waste world's resources.


I also learnt from Stuart where their MX is made - Indonesia (he did tell me the company name but I'm not going to reproduce it here obviously!). Indonesia is an obvious place for it to be manufactured, considering how much batik is made there and it being an ideal cold water dye that won't melt wax. Stuart assumes it is also still made in India.

loose dye update

The Procion samples had two excursions into the washing machine. First in a pillow case then, as I felt they wouldn't have had suitable exposure to the elements, in onion etc plastic mesh bags. No apparent change in colour intensity. That was before Christmas.

After three weeks 'airing' in my studio, I dropped them into tubs of just-boiled water. Or rather the second lot went into partially cooled boiled water, as I could smell the first lots' plastic tubs rather more keenly than desired. Yes, a lot of dye came out, immediately. I agitated them often, with a hazel stick (in case it's relevant!). The amount of loose dye after an overnight soak was close to the same amount as came out after the first wash/soak. I am bewildered!

They have been rinsed three times (collectively), with plenty of agitation and kneading incorporated. The final rinse/soak water hinted pink. I didn't rinse again, but hung them to dry.

And now dry, there is still no perceivable colour loss. And so...

- If the dye was excess or loosened in the washing machine then why wasn't it all rinsed out there too?

- Has three weeks exposure to air loosened the dye? Impossible surely. But also among my first posits.

- Does Cornish water affect the dye? It's mildly acidic. Perhaps I should alkalise the water and try rinsing again?

- Why, how, can water rinse clean (or nearly clean) and then time after time after drying release more dye when re-wetted?

organic cotton from seed!

I bought a cotton vest in Padstow recently, in Seasalt, an accredited ethical clothing company based in Cornwall. Not only is it certified organic cotton, it's a gorgeous colour! By luck it was in the sale though buying it wasn't a spontaneous consumerist response to finding a "bargain". I have been on the lookout all summer for a vest (organic, fair trade), my old two being over 10 years old and anyway... lost! A vest was a "need" not a "want", and I managed not to be seduced by any other delightful things in the shop.

What was a bargain was discovering one of the attached labels was in fact a packet of seeds! It advises me I can sew them in the summer (inside on a sunny windowsill) and later plant them outside (in a sunny place)... and to water them well. And regularly remove pests such as aphids or caterpillars. Later they should flower and (if there's enough sun) the resultant bolls will open and produce cotton. And seeds for a new crop...

This is very exciting! I am just frustrated at having to wait six months to start... and curious about whether Bodmin Moor, let alone Cornwall, has enough sun for them to flower. And if our inconsistently wet weather would mean I'd still have to regularly water them. Whatever, I hope to learn a lot about cotton growing. I'm sure it won't be easy.

I just took a peek inside the packet – there's three fluffy seeds looking quite unlike seeds I have ever known.

slow travel, slow talk

Three strangers, three conversations. Had I driven (as would have been my former inclination as everything could be visited (ie "done") in a day) then I would never have met these people, never would have had such interesting and stimulating exchanges with them. But as I travelled slowly, walking or by train (other than lifts to and from home, and one to a railway station), taking two days, there was time, and so I did. Taking it slow and being away also made it a mini-holiday and back home I feel energised and invigorated...

I went to Slimbridge, Britain's first wetland nature reserve last week. I travelled on to Bath to see the Batik Transitions exhibition at the Museum of East Asian Art, staying overnight in Bath Youth Hostel. Here is the first conversation, I will post the others later.

Conversation One
After being dropped at Slimbridge village by my lift, I enjoyed a pleasant half-hour's walk from the centre past cows moving field and a working canal lock-bridge. Just before the centre a sign invites you to view and read about their reed bed filtration system. All their waste water and sewage is filtered through several stages including gravels and different plant groupings. All the nasty bits for us are food for bacteria that live in the reeds root network. Clean water eventually flows out into a wildlife pond, proof it works! Adam Joseph Lewis Centre at Oberlin College both incorporates a reed bed system in their building and explains its workings well.

Last year I researched wax removal processes*, including disposal of both used wax and the cleaning agent (in my case, boiling water). It included the effects of disposal via the sewer, which I contrasted with direct disposal into the ground. But disposal via reedbed filtering hadn't crossed my mind so I seized this moment to learn more (had I been driving I would have already left, because of the intention of "doing" Bath in the same day). After a phone conversation or two, a WWT specialist met me and kindly gave some outline advice for my situation.

A reed bed filtration system would probably be impractical due to scale. Scale of my practice more than scale of space needed for filtering! The system would need to be regularly "fed" waste water to stay active/alive, so including household waste water/sewage would make sense. Umm, what about when I go away, say for two weeks? Yes, not advised, it's long enough to starve the reed bed. I pondered collective action as a solution but feel in my street only one household might consider it without thinking it weird. For now, anyway. Who knows about the future?

Every reed bed system needs to be designed precisely for the potential waste it receives, so my hypothetical one would need to take dyes into account as well as waxy water. Chemical dyes and natural dyes – I am still considering switching to natural dyes. Procions would need more than a casual conversation to analyse but I feel in the doses I use they would break down sufficiently and harmlessly (in the early 1990s I sought advice on their disposal via mains sewage from someone working for the then National Rivers Authority and a housemate working for Severn Trent Water authority; both OKd them). Natural dyes also might affect micro-organisms within the reed bed – they are essentially chemicals too. But what was made apparent during the talk was incompatibility of inorganic materials to reed bed systems – such as metal mordants used to fix natural dyes.

I have read and heard from time to time that chemical dyes are (or can be) more environmentally friendly than natural dyes simply because of the mordants used for fixing most natural dyes. I really doooo need to look into this properly... and the carbon cost of both. I also have an inkling that wood ash or just plain wood can be used for fixing. Indigo wouldn't have the same concerns, not requiring a mordant. Not to say it wouldn't introduce other problems.

But the biggest problem to adopting a reed bed system at my studio and house would be location location location... the garden slopes uphill from the back of the house. Aaagh! Completely the wrong direction! But a point to consider for when I move...

* The wax removal article needs a bit of amending before being posted here, I will try to do this soon.

bucketsful of water

The wet change in the weather reminded me that in this earlier post I described my surprise at the amount of water needed for dip-dyeing fabric and was going to suss how much was being used.

A length of prima cotton measuring 104 x 170 cm and weighing around 200 grams used between 80 and 107 litres. This was made up by 20 litres initial washing and rinsing, 5 soaking the cloth prior to dyeing, another 5 for the initial dye bath plus 1.5 used to dilute the salt and soda ash, and finally between 50 and 75 for final rinsing, rinsing and re-rinsing. When I switched process to overdyeing with a second colour (to achieve the intended wet sand colour) an additional 60 - 86 litres will have been used (the same as the first dyeing less the initial wash/rinse), totalling 140 to 193 litres.

These figures are way too high! Think of it in terms of milk or beer or petrol. No one would sensibly consider wasting 140 litres or 246 pints of Tribute, for instance, in such a way.

I can see ways to re-cycle the 'waste' water such as the initial soak water doubling as first dye rinse water. All used water could be stored for re-use as bucketed toilet-flush water instead of just the occasional bucket or two I did chuck there (though storage isn't too practical due to small bathroom size). According to uswitch.com toilet flushing uses 8 litres a go and this activity accounts for a third of our average daily use of 16 bucketsful of water. And to think I used 14 buckets-worth just for one dyeing!

When travelling in Australia and New Zealand I occasionally came across army personnel returning from training or just travelling across country, all very friendly and sociable (what sort of Aussie or Kiwi isn't!). Generous too, they often gave me their unused ration packs - high energy biscuits especially. An Aussie told me that they were trained to survive in the bush on just 4 (or was it 6? or 2?) litres of water a day - drinking, cooking, washing the lot. A real jaw dropper for me who drank 3 or 4 litres daily! Of course some water doubled up its uses, so for instance water that tinned food was cooked in could afterwards be drunk, or used to re-hydrate other food, and then for shaving. Other than drinking, I tried rationing my water for a few days to 4 litres and it wasn't much fun.

Yet many people in the world get by on twenty litres a day. If they can, can we? OFWAT reckons British household daily use is 352 litres, working out at 147 litres per person. About the equivalent for dyeing my cotton.

Being on a metred supply I can calculate my average daily water use. My bills show I used 45.9 cubic metres, or 45,900 litres between 22 February 2006 and 17 April 2007 (420 days). That is, 109 litres per day. The six months to the 25 August last year it averaged at 93.4 litres/day. The previous year it was 112 litres. But I am not smug or complacent - all are still a lot of water whether you compare it to bottles of Tribute, developing world use, or army rations.

And so, as part of sustainable batik practice and daily lifestyle I aim over the next year to further reduce my daily water use to below 80 litres (for starters).

As well as looking for ways to re-cycle dye-related water I should think more about harvesting rain for dyeing purposes. Currently I store rainfall from my shed roof for watering the garden, but because of living mid-terrace, with a right of way along the back impeding placement of a downpipe and butt, I haven't harvested rain from the house roof. At the moment it runs off into the mains sewers, such a waste (of water and of downstream re-treatment). Being able to harvest roof rainwater is one priority for when - eventually - I move house.

more about salt

Found this informative site about traditional salt pans in the Algarve (and west coast of France) - Flor de Sal. Interesting pages include a description of the traditional harvesting process, differences between Flor de Sal, traditional and commercial sea salt, and rock salt (also a good description of all you could want to know about sea salt), and a table giving similar differences between the various salt pan types. Here is some stuff about the history of salt and a pic of salt pans.

And here is a quick overview if you don't want to trawl through those: salt is the next most used raw material after oil; in earlier days it was the cause of wars between nations (consider Gandhi's peaceful demonstration against the British-imposed salt tax) and was so tradeable and highly regarded that some people were paid in salt. The word salary originates from the Latin salarium meaning 'payment in salt'. Traditional harvesting methods date back to at least the Roman Empire and may have been introduced to the Atlantic coast by Phoenicians. By the year 1000 the Portuguese were trading salt over most of western Europe.

Pans, or holes in the ground, hold and allow sea water to evaporate, with the remaining minerals gradually crystallising when certain densities of mineral to water are met. Calcium carbonate is first, followed by sodium chloride (89% of the mineral content in sea salt). Other trace minerals include sulphate, magnesium, bicarbonate and potassium though there is such a long list that you might assume it was contaminated! After a few weeks the pan is dense enough with salt and it is raked out into piles to sun and wind dry.

In commercial panning the evaporation area is larger so by the time the water reaches the crystallisation areas it is already crystallising into sodium chloride and is mechanically harvested before magnesium salts crystallise. Remnant water is then removed and the next sea water received. It is a process to maximise efficient sodium chloride production for industrial purposes. Oh, road de-icing is the world's biggest use of salt.

Rock mining extracts sodium chloride from areas that formed in a way similar to the panning process - this salt originated from sea water too.

Flor de Sal is an intermediate process in traditional harvesting whereby the salt piles are delved through daily by hand to find largish salt crystals forming on the surface. Workers took it for their own home consumption and it is still considered the cream of the crop, having the highest trace element composition.

So now that I'm a bit more informed... I feel even the traditionally harvested salt is far too good to be used for dyeing! It's too healthy by being too mineral laden! But when I see how much they rake up - every few weeks - what I take seems to be so minimal as to be of little consequence. And when I think about the alternatives - commercially driven salt panning or mining - then I come back full circle to traditionally harvested. What I should find out is whether they have a lower grade salt product in the way that Flor de Sal is the highest. And now I know the mineral composition of this sea salt (and of the mini-market salt "salt, anti-caking agents (magnesium carbonate, sodium hexacyanoferrate)"), I can endeavour to find out what happens to them after dyeing and going down the drain. For another day.

take me to the river, drop me in the water...

I read the water meter today. Usually it's the water company owing me money... but this time I was feeling apprehensive: over the last few months I have been dip-dyeing...

It was for a long-standing commission which requires a flat evenly-coloured background. The colour is something like the colour of saffron, cardboard or wet sand. Achieving an even colour over a large area by painting dyes on is not easy, but is - or should be - a doddle by dip-dyeing. I've dip-dyed the odd piece of clothing in the past, but nothing where the colour and even-ness was as paramount as now. So I had some learning to do.

To get the exact right colour took over ten attempts... boy was this a learning curve! My initial problem was in getting the right dye dilution to achieve the right tone. I mixed my own exactly-right wet sand colour from the Procion primaries (cyan, magenta, yellow, black as I call them, though didn't use cyan this time) and diluted this down, initially 3 or 4 times, later 8 times, with water. The first few dyeings came out gorgeous deep reds - stunning colours though, I love them and they will not be wasted! Try as I did I just couldn't get the final dip-dyed colour to resemble the initial one I mixed. They were new dyes, freshly mixed, so that wasn't the problem. It seemed that the reddish or magenta "pigment" (do dyes have pigments?) fixed more readily, strongly and quickly than whatever was left - Ian Bowers at Fibrecrafts later confirmed this with a technical explanation, including a fascinating account of how exactly the dyes go about (literally!) their chemical process of binding to the fibre.

Suddenly I understood why pre-mixed Procion colours are there on the market... if your initial colour isn't going to relate to your end colour, then how can you mix the initial colour that will? Ian's suggestion was to dye twice, first green then orange (my wet sand came from mixing a yellow-black green into a yellow-magenta orange), though I dyed the orange first. He also floated buying a pre-mixed Fibrecrafts colour though this easy way out was stalled by their range not having a wet sand colour - and besides, I wasn't yet defeated! But I did buy an orange in the hope of overcoming the reddening problem. Although the legwork had doubled, overdyeing the green instead of pre-mixing it into orange did the trick and after a few more attempts sussing quantities, I got... wet sand!

Experience is without doubt the best way to learn, and had I achieved what I had wanted on the first attempt I would have learned nothing. I'm grateful to Noel Dyrenforth, Rosi Robinson and Fibrecrafts for publishing dip-dyeing recipes (the first two in books, the latter on their website) that initially guided me. The method, quantities and proportions are now in my head and moving into my instinct (from where I prefer to work).

Quantities brings me back to water. Yes, dip-dyeing uses tankfuls! After the first few dyeings I felt I should start measuring the litres but didn't - it wasn't the right time to shift focus. But I will have a think and post that suss later.

Dipping also requires a lot of salt. More easily calculable, I went through six or seven 750 gram containers. The packaging gives no information at all about the salt's origin or method of production. Although I bought these from the local mini-market (walking distance) I will start looking out for salt packs listing origin and production so I can research and get properly informed before needing any more.

I do know where my water comes from - and I don't mean the taps! Five Lanes' water comes via a small works beside Withey Brook, a moorland stream on the far side of East Moor. Rushyford Water, one of my Bodmin Moor river batiks, flows into the Withey. I like it that I can walk across the moor to see and appreciate the source of my water. I had never realised before living near the "supply" how anonymous my water was.

How come South West Water usually owes me? We agreed some time back that I use about 7 or 8 cubic metres/quarter and pay £14 monthly. But 3 x £14 comes to more than the cost of 7 or 8 cubic metres, but they won't take less than £14/month. I did give myself a pat on the back for assumed resourcefulness... until I read that my water footprint is still way above the global average. I will write more about this later too.

South West Water are sending a new bill... yes, this time I owe them.