Friday, May 8, 2009

Dyes and Pigments

Just in case you are unsure of what I was doing with my piece in last week's blog, I shall precis it here. First there needs to be an understanding of dyes and pigments. There is always confusion between these two products.

Procion MX Dye: a coloured powder which is dissolved in water, and along with additives such as soda ash, urea, and Manutex thickener (sodium alginate) if the dye is to be used as a screen printing or thickened paint application. The urea is there to slow the chemical reactions so that they process longer when cold batching. This needs to happen to allow time for the chemicals to react with the fabric, before washing to remove surplus dye. If Procion MX is used for immersion/bucket dyeing, then salt replaces the urea as there is no need for cold batching. Procion MX are fibre reactive dyes ie everything works together to react with the fibres.

Pigments: These are colour molecules suspended in a textile base. This may be a thickened base (similar to yoghurt) so that the pigments can be used for screen printing and painting; or a liquid base which allows for the spread of colours as in silk painting. They are water-based. To bond pigments to a fabric they need to be heatset after air drying, usually by ironing. Pigments will alter the hand of fabric ie make it stiffer.

The majority of the colour on my WholeCloth Banners is done with dyes and then they are often finished off with a pigment. There may be 10 – 15 applications of Procion MX dye applied using dye thickened with Manutex, each left to cold batch, and then washed to remove any surplus dye (yes, this does mean 10 – 15 washings!). I may also over-dye a whole piece (immersion with salt) and/or discharge portions with discharge paste.

All the in between washing means that when I apply some pigment, the dyes underneath are stable. So.... if I am leaving pigment to air dry, then wash out to avoid it being too over-powering, the dye underneath will not shift. I don't always do this, but it does seem to work on areas of solid pigment which I may have painted on, or screen printed. Any stiffness in the fabric has now been greatly reduced.

Here is another detail of my Three Brothers Tomb. The border on the right and the sweep below across to the left were painted with a pigment colour which I had mixed. At this point they blocked-out all the dye colours underneath. The pigment was left to dry, then scrubbed in the bath. This removed some of the pigment and now the dyes underneath are still able to be seen. I could have done this with the Procion MX but as this piece has had many applications of dye it has reached a saturation point and would have been ineffective.

Hope this helps. Next blog will explain the pigments I use.

Monday, May 4, 2009

Breaking the Rules

One more image of The Three Brothers Tomb. Currently the sides are hand hemmed, and the tops and bottoms are awaiting stitching when my machine becomes available.

My WholeCloth Banners are dyed using Procion MX cold water dye. I am able to achieve all sorts of outcomes with these. However, there does come a point where yet another layer of dye will not be effective, the fabric has absorbed all it will take and/or another application is not going to give the depth of feature I require. This is when I move on to using a textile pigment/paint (the screen printing type). I have fairly large containers of pigment in just a few basic colours as I prefer to mix my own colours.

When pigments are applied to an already dyed piece, and because they are opaque, they will often appear too heavy particularly if painted as a block of colour. To overcome this I will leave the pigment to air dry for a few hours (but no heat setting at this point), then take the piece to (depending on the size) the bath and while it is soaking, scrub the pigment painted area. Surplus paint will come away leaving a much 'softer' appearance, allowing dye colours underneath to show, and will not make the fabric stiff which is a disadvantage of pigments. Then the fabric is dried and the pigments heat set.

The white area behind this mummy is pigment, initially very opaque. Scrubbing has left it transparent and, in reality, it does show more of the dye colours underneath than appears in the photo.

Everytime I go to the library I like to grab an art book to browse during the following week or so. I deliberately don't choose a textile-related book. It is surprising what one can learn. Last week I brought home a recently published book on John Drawbridge, a well-known New Zealand artist who died in 2005. The book is full of paintings and artworks, quite inspirational.