Serti technique is a particular reserve dyeing technique, used to paint on fabric.
It is suitable for any kind of subject, but it is essential to make drawings with closed shapes.
Gutta-percha, a waterproofing that prevents colour from expanding, is applied to contours.
The ideal design has therefore well defined shapes and a clean graphic structure, consisting of closed shapes, avoiding large background surfaces, or too small and meticulous details, more suitable for direct painting.
Materials and equipment
- Worktop (a table)
- Wooden frame and drawing pins
- Cut of fabric (Habotai silk is very used)
- Brushes and pads
- Gutta-percha and water-based specific colours for fabrics (available in fine arts shops)
It will take a good table on which to place your frame. Frame is essential, because fabric should always be detached from table’s surface.
In case dimensions require it, frame should be supported by stands.
You can choose to work seated or standing, but in second case you will have a more complete overview.
With a plastic towel or with old newspapers protect the working area.
To stretch fabric well, which must not come into direct contact with table, it is necessary to use a frame.
The more fabric surface is stretched on a regular basis, the easiest will be the entire work.
Different types of frame are commercially available, but the quality of wood is an important factor, because to stretch fabric you will use drawing pins.
To realize a simple frame choose four strips of seasoned wood (section 3-4 cm, lenght from 60 cm to 1 m approx.), and with a a hacksaw make some notches at regular intervals. (Notches allow to assembly your frame according to the size of fabric).
In the photo example, each notch measure 1,5 cm in length and depth, and is about 8,5 cm from the others.
By applying some drawing pins, you can attach your fabric sample to the frame.
There are different types of pins: those from architect (three-pronged) have the advantage of penetrating completely into wood.
It is important to always start from a corner, fixing fabric to the frame every five cm, and proceeding on the side perpendicular to the previous one.
After a little practice, a good tension of fabric will require less pins: a square of silk of 45 cm (side) has 4 pins to the 4 angles, and 2 pins on each of the sides.
Brushes and pads
The most suitable brushes for Serti technique are those used for watercolour: round, soft and with a thin tip.
For all backgrounds it is better to use a flat brush, or to use some pads.
To prepare a pad, tightly ball up a piece of absorbent cotton, then wrap a gauze around it and stop the whole thing with a clothes peg.
For more limited surfaces use simple cotton-buds.
Pads and cotton-buds, each for one colour, must be discarded after use. Wash brushes immediately after use in a bath of lukewarm water and mild soap, or pure alcohol.
Washing operations must also be carried out when changing colour. Dry residual water or alcohol thoroughly to avoid stains or halos.
Specific Serti technique colours to paint on fabric (silk, cotton and sythetic fabrics) are available in fine arts stores, ready for use and water-dilutable.
The range of available colours is usually wide in assortment.
In addition, there are other types of colours in a concentrated form: professional inks for silk an wool, 50% water or industrial alcohol dilutable.
Gutta-percha is a resin. It comes in the form of dense and semitransparent liquid (but coloured variants are commercially available).
Once applied and dry, it becomes a rubbery substance that adheres to fabric, making the treated part waterproof.
Colorless gutta-percha washes away after fixing.
Motifs are realized by first tracing contours with gutta-percha, which once dry, prevents liquid colours from expanding beyond the established zones.
The first operation is therefore to draw your pattern using a frame as to stretch fabric.
There are different possibilities:
- Tracing a previously prepared model, using a pencil if fabric is sufficiently light or – in case fabric is heavy – carbon paper, taking care to trace the signs with a light hand.
- Freehand, using a pencil (although it is advisable to follow preparatory sketches) or for the more experienced, directly with gutta-percha, without any guiding path and following the inspiration of the moment.
The important thing however, is to circumscribe in close forms all the colouring areas.
Next step: gutta-percha. You can use a brush or a specific applicator: a soft plastic container, provided with a cap, to drill as finely as possible with a needle.
In order to obtain a thinner stroke you can also screw a special tip.
Residues should be immediately eliminated, cleaning the container.
Colouring is the penultimate stage: if gutta-percha is dry, you can paint inside and eventually outside resin strokes.
Colour must be given starting from the center of the surface, leaving it to reach up to the contour line.
For the final drying phase: simply follow the indications given on the colour packages. Usually it is enough to iron on fhe reverse side of fabric.