Tuesday, 11 September 2007

organic cotton - Procion dye 1

Following are observations I made last month after hand-painting Procion MX dyes on to the organic cottons.

Summary: Dye was absorbed fine on prima, white percale, and seemingly Bishopston handloom. Dye wasn't fully absorbed to the reverse side on Fabrics handloom, voile and natural percale, though it was marginal on the handloom. On powerloom it had hardly penetrated to the reverse side.

Hence powerloom requires a serious attempt at scouring. To compare results I will do equivalent tests on all other fabrics. I see two levels of scouring – boiling in water with soda ash and soaking in warm water with soda ash. The powerloom is so heavily opposed to receiving dye my inclination is to start with boiling and if that works try again with warm water. If it doesn't work... well, I'll decide then!

After boiling out I found the dyes had fixed adequately on all cloths except, as expected, the powerloom. Colour was lighter on the reverse of the natural percale and marginally so on the voile and Fabrics handloom, due to incomplete penetration of dye. It was fine on the others.

This said, on comparing the boiled-out results with unboiled test strips two things were apparent:

Firstly, the cyan was consistently not as intense as it should be, suggesting the dye is already past its shelf life (though bought only in December 2006 and not opened until early August when starting these tests). I also was aware of more cyan colour emerging into the boil-water. Remnant colour here tends to be "loose", not re-bonding with the fabric. But even with the first batch of prima and the two handlooms the cloths have taken on a bluish tint, more apparent in the handlooms than prima. An explanation could be that the boiling-water was the same water plus soda ash used for scouring the cottons for indigo dyeing, and that the loose dye has re-acted with the soda ash and cloth. Additionally I had applied fix to a further area of each test but abandoned original plans to dye it in the first stage, so there was "free" fix around from here too. But "blue tint" has happened a few times in the past - on individual cloths in plain water – so something else could be happening... but what? Or is it just down to old dye?

This "free" fix and/or (my feeling) the badly-fixed powerloom dyes might be responsible for some other unexpected dye transfer on to the voile and Bishopston handloom by getting wet and being temporarily in contact with the powerloom, which also shows signs of dye transfer.

Have I got it in for the powerloom? Am I giving it a hard time? Yes! Yes! Yes! Just as well really,if everything was working perfectly I'd feel my tests weren't adequate!

Secondly, intensity of the other three dyes is as expected after boiling out, but the unboiled test strips are so much deeper that I perhaps could look again at the recipe I created back in the early 1990s when first starting batik in this country. At that time, I ran tests that gradually increased the proportion of dye to water until the maximum intensity of colour after boiling was reached. That recipe is one level 10 ml spoonful of dye powder to 300 ml water (whether or not urea is added to the water to prolong drying time and thus intensify colour). It would be great if less powder achieved equivalent results!

More than showing the outcomes, the photo highlights the limitations of technology and superiority of human eye. In real life all dyed areas of all the cottons have similar hues and intensity (except powerloom) including voile, which only appears darker because of shadow showing through its loose weave. Certainly none are as red as the photo suggests they are.

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