An intaglio is a print created by incising or etching a line or texture into a metal plate. This line or texture will hold ink that can be transferred to another surface (usually paper). My prints are created from both copper & zinc plates and incorporate line etching, rosin aquatint, dry point & chine colle. There are many other techniques and materials used in intaglio printmaking, but I will be addressing the specific processes I use.
A line etching is produced by coating a plate with a very thin layer of a liquid ground (or resist). Once the coating has solidified, it can be drawn though. The lines drawn expose the metal beneath the ground and the plate is submerged in a corrosive liquid. For my work I have used ferric chloride to etch copper plates and nitric acid to etch zinc plates. The amount of time the plate is left in the corrosive determines the depth of the etched line or texture and the intensity of the mark when printed.
Dry point lines are those that are incised directly into the plate with any kind of sharp tool. It can be a single scratch, a continuous line or an entire abraded area. The resulting marks have a soft, feathered feel to them and depending on the depth of the mark can evoke the feeling of a ghost image or be incredibly intense.
Rosin aquatint is used to produce shaded areas and texture. The bare metal plate is coated with a very fine dusting of rosin (the dry, powdered resin of a conifer) that is then cooked onto the plate until fully adhered but not burnt. Ground is used to block any areas of the plate that are to remain unshaded. The plate is etched in the corrosive which eats away the tiny areas of exposed metal between the rosin dust. This gives the plate a very fine, pitted texture much like sandpaper. When inked, it will hold the ink to varying degrees depending on the depth of the etch. Darker shading is obtained with a longer etch time and gradations of tone can be achieved by blocking out the area in stages.
One of my favorite ways to produce an aquatint is by using the sugar lift method. Sugar lift is essentially a mixture of simple syrup, india ink and gum arabic (there are several variations on the recipe). The solution is applied to the plate with a brush, stick, or any tool the artist chooses to create a variety of painterly marks. When the solution sets, a thin layer of liquid ground is applied over the plate, dried and then submerged in a bath of warm water. The sugar lift will literally lift off the plate, exposing the metal and retaining the quality of the mark made. Rosin is then applied to the area and etched to create form, tone and shading.
Chine colle is the application of a second paper layer (usually fine, Japanese rice papers) to the main paper used for printing the image. Typically, the chine colle paper is the size of the plate while the main paper body is larger, allowing for a margin. It can also be used to accentuate specific areas of the plate or to create a greater "collage" like effect. There are several ways to adhere the chine colle paper but I use a dusting of wheat starch powder to the back of dampened rice paper. The clean side is laid over the plate and the rag paper is laid over that (from bottom to top of the layering would be: plate etched side up; chine colle paper clean side on plate, dusted side up; rag paper on to). When run through the press, the chine colle paper will be adhered to the rag paper with the etched image imprinted to it. This allows for added tone, texture and depth to the resulting print.
The finished plate is printed by wiping ink over the surface and imbedding it into all the fine lines and textures. The surface ink is completely wiped off so that what remains is the ink in the etched areas below the surface. Very minimal amounts of ink (more like a haze of color) can be left on the surface to create "plate plate." Intaglios are traditionally printed on damp, cotton rag paper to facilitate both the transfer of the ink and the embossing of the marks. However, any medium that will withstand the press and allow for the image transfer can be used.