Friday, 23 February 2007

A while since I was here

First published 9/07/2006

A while since I was here, mainly getting on with things, life being more than my meanderings with pigments.

The lakes have gone well, in that I am pretty convinced I have the handle on brazil and weld. Weld does indeed give a bright yellow pigment, no surprise really since it yields a yellow dye.

A few weeks back I picked up a rather small, dried yellow stalk of weld from a Little Chef or some other non-descript road side 'food' place and absently put it into my back pocket. An hour's drive later to Hampshire to visit some friends, we were en route back from Ilminster and wanted to break our journey in Headley, I was asked by wife and wife's friend why I had strange yellwo streaks on the back of my new trendy shirt. The little stalk of weld had, with the sweat of my back, leeched out a very fine and deep yellow, much to my wife's chagrin, as it was she that had gifted me the shirt in the first place. But instead of being contrite I was jubilant because I had noticed that the yellow was a much deeper sort than I had previously managed to get from green weld. Anyway as the yellow wasn't mordanted to the shirt it was washed out easily enough. A subsequent conversation with a traditional dyer revealed that she had too suspected a yield difference, yet because the dry old past-seed weld looks washed out there was an assumption of less colour. The two of us had that odd look of revelation about us as we imagined the increased value of the yields for dyeing and pigment making, respectively.

My soon to be four year old daughter is now a weld afficionado, a veteran of a good half dozen weld gathering missions in various parts of Suffolk and Hampshire, she can spot a clump of weld as well as I can.

I am worrying that the late summer months become a bit of a haze of me keeping a watch out for clumps of the stuff, sadly much of this fantastic plant grows along the hard shoulder or other equally inconvenient places that I can't stop at. Imagine my sheer frustration when being caught in an hour long traffic jam outside Newmarket and seeing the largest clumps of Weld to my left, I was in the inside lane, so could have stepped out in a mad frenzy of weld gathering, but refrained, but next time.

for those who want to see this plant but not want to be travelling at 70 mph to do so can check out weld here.

A good wash

first posted 2/24/06

Good washing of the lakes is important lest residues of alum or the lye remain, this shows up as a bloom when drying in the dish, you knwo when the lake is clean when no bloom rises when left standing for a few days.

I attempted to liberate the brazil red colour in oil, some plants liberate colour in oil, brazil did not, at least not in cold oil, I suspect it wont in hot either. The idea was based around the principle of creating an oil glaze straight off rather than making a lake then drying it then grinding it with oil. I guess the insolubility of the brazil is why I can find not one mention of such a process but dozens about using lye and alum etc for creating the lake in the first instance.

Also I found out that hard water has an adverse effect on brazil, I normally used boiled water but lately forgot and it meant that much of the calcium (carbonates/sulphates?) in the water reacted with the alum and pigment creating a useless sediment on the bottom of the test jar. It also seemed to reduce the yield. I realise that the red is increased by adding alum but this was a noticable drop in yield, so all water must be low in mineral content. I understand that dyers have to take into account the hardness of water in their regions.

Madder lakes coming soon, had a quick go the other week, results were that the colour is a brownish red going to garnet depending on pH, made a nice peachy pink chalk precipitate with it though, but am looking for the reds mainly.

lyes lyes and truths

first posted 2/22/06

I had success with the lye after reducing the concentration, nice transparent lakes so far. Adequate preparation of the lake is needed prior to use.

Colour tests underway with opaque variants too, showing some promise.

Caution: lye is very corrosive in high concentrations.

The lye is also useful for cleaning oil based paint spills on the slab as it effectively combines with the oil to make a self-cleaning detergent. Not that easy to clean brushes though as the hair is vulnerable to decomposition.

Highly concentrated lye will rot animal hair, some wool left in a small tub of lye was reduced to a jelly like substance.

Fun with lakes

recovered from my corrupted 'Experiments with colour'

For the last few months I have been experimenting with producing a variety of lakes from brazil wood using known recipes going as far back as the 14th century.

Mostly the results have been quite predictable, in that an alum based with wood has yielded a cherry red lake. Chalk precipitates of this have given a range of opaque colours going from pale cool pink to almost purple, this is dependent on the acidity of the lake and the amount of chalk ground in.

The best thing about scraping chalk into the lake is that it decomposes, ie does not retain much of its structure as it combines with the alum and the brazil colouring. Upon drying it is easy to grind any of the few granules that are left.

On top of this I have been trialing making transparent precipitates using caustic soda solution as a substitute for wood ash lye, mainly for my own convenience. Initial results were poor as I had made a far too alkaline solution and it resulted in a colour that corroded the paper substrates.

The solution strengths are under review.

Also coming up will be weld and madder lakes, again close attention to the alkali levels in the soda/lye water. Medieval methods of testing optimum concentration were to see if an egg floated in it and did not corrode the shell. This method seems fair enough.