General information | Other color printing methods | Combined roll-up and intaglio printing | Viscosity printing | Colored paper | Crossover techniques | General information
In the intaglio medium color prints of great richness can be achieved in the intaglio medium by using a number of different color printing methods. The main advantage of using intaglio techniques is that they can facilitate a range from a highly saturated deposit of densely pigmented printing ink to the faintest translucent layer of color.
In the simplest color printing method known as a la poupee, different colors are printed from a single etching plate; while in the more demanding method of multi plate printing a set of plates are made, each plate inked up in a different color and then successively printed onto one sheet of paper. This way of working may be more laborious than the single plate method but often more richly interwoven layers of imagery are produced.
Color etchings can be printed from virtually any kind of plate commonly used in intaglio printmaking. If zinc is used its effect on the warmer palette – yellows, reds, oranges – should be tested beforehand. Copper plates (even steel-faced) rarely affect colored inks while steel or aluminum plates are not known to alter their appearance at all. Sheets of Perspex / Plexi / PETG and other plastic surfaces such as collagraph plates coated with floor varnish or other acrylics, or photopolymer plates are also entirely inert as regards color printing.
All intaglio techniques, such as open bite, line bite or aquatint can be utilised for color printing, but for many projects aquatint is the favoured tool as it ensures an even deposit of rich color and makes the layering of colors more predictable than with other techniques. Often color etching plates benefit from being etched slightly deeper than a monochrome plate because many colored etching inks have a considerably lower opacity and density than the black inks. When a set of the three primary colors is used the addition of a black plate may be considered to enhance the definition and tonality of the image and to intensify the dark areas.
If, for example in a set consisting of a red, a yellow and a blue plate a pure blue is to be printed in a certain area this could be achieved by having a deeply aquatinted patch on the blue plate; while the red and yellow plates bear a polished plate surface in that area. During printing both the red and yellow plates would be wiped extensively with tissue in this area to allow the pure color from the blue plate to come through on the print. In keeping with color mixing, areas of the blue and yellow plates that overprint would produce a green; and where all three colors meet a range of earthy browns, greys and blacks will result.
In multi plate printing it is essential to use a precise registration system and to make sure that all individual plates areidentically sized. This way the artist can produce a colored etching that is neatly framed within the paper as if only a single plate has been used. Discrepancies in plate sizes will lead to a mismatching of the embossed plate mark and spoil the print. Of course, artists make wish to experiment with overlapping plates. If a more conventional result is required, the following is a basic outline of procedure:
METHOD
A basic method for multiple plate colour printing is as follows:
The most useful system for printing multiple colors is simply to create each colour plate in succession. The inking and wiping process for multiple plate color etching is similar to the monochrome process, but to safeguard against contamination it is essential to use delicate pieces of scrim for each colour and to keep inking and wiping surfaces for each color separate on the work bench.
Wipe all your plates in their respective colors before printing commences.
1. Etch the first plate using the various techniques available and then print in the usual fashion.
2. Once the print has been pulled, lay the paper face up on the press bed and place the second plate on top, aligning the embossing.
3. When the bed is run through the press the image of the first plate is offset onto the second plate. This can now be used as a precise guide for the production of the second color plate, and so on for all subsequent colors/plates. It is now possible to predict with accuracy which marks and color fields on different plates are going to overlap – producing mixed tones, and which are going to remain pure.
1. Take the first plate and register it on the bed of the press, cover it with a blotted sheet of etching paper, and then run through the press. Once the bed has emerged on the other side, the edge of the paper is kept firmly trapped between the rollers.
2. Carefully fold the blankets and sheet of paper back over the top roller and remove the first plate.
3. Now position the second plate and a fresh piece of tissue on the press bed and lower the paper and blankets before operating the press again.
4. Repeat this procedure until all plates have been used. The resulting image will bear evidence of all the colors used individually and the tonalities created by overprinting.
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Useful Tips:
When using a range of colors, the best printing order is from yellow to red to blue and finally to black. If inks of varying viscosity are used it is recommended to print with the stiffer ink first. It can be better to print the most heavily embossed plates last. Make sure you plan and co-ordinate a swift execution when printing multiple colored etchings as etching paper can quickly dry out and shrink if left exposed for too long. On especially hot days, this can be prevented by lightly spraying the back of the sheet with water.
The registration system outlined earlier is very useful for multi plate printing if the markings are accurate. Some etchers also make use of heavy metal blocks or rulers to aid registration. Before the first plate is removed after printing, its position is marked by aligning the blocks along two adjacent edges. The next plate in the sequence is then simply placed in the resulting L shaped space. When the blocks are removed, the next printing can be carried out.
METHOD
The plate-on-plate color printing method is as follows:A very unconventional but nonetheless effective registration system takes a different approach to getting all the plates in the right position.
1. After printing the first plate, lift the printed sheet off and remove the plate.
2. Now place the sheet face up on the press bed (sometimes cushioned by a single fronting blanket) and place the following plate face down onto the image – matching the edges of the plate to the embossed plate mark made by the first plate on the paper.
3. Operate the press.
4. Any subsequent colors are added in the same fashion.
Even though this method seems to contradict good printing practice, the etchings that result can be perfectly registered (with care and precision) and also extremely well printed. Traditionally, multi plate etchings are printed from etched metal surfaces, but with the introduction of the intaglio type the creative possibilities for color printing are greatly extended. Non-etch photopolymer plates, particularly, have a number of properties that make them ideal for color printing. Photopolymer surfaces do not interfere with colored etching inks like some metals do; and often the crucial job of cleaning all ink off the top surface of a plate is achieved with much less effort than on conventional types of plate. A colored composition can now be worked out with the same ease and control as in the medium of screenprinting; positives for individual color plates are generated by hand or reprographic means and the overall composition can be monitored by overlaying them on a light box. Since the actual plate making process is much faster, a greater number of colors are more feasible than with etched metal plates. In view of the fact that many color plates are made to provide background colors for a main intaglio plate, photopolymer plates exposed with the aid of an aquatint screen provide an ideal alternative to traditional aquatinted color plates.
On a technically advanced level the intaglio type medium can also be used to print photographic four color separations in intaglio. Keith Howard’s recent research shows how it is now possible to match the accuracy of industrial reprographic printing.
Other color printing methods
The method of a la poupee printing is most successful when the plate is divided up into clearly defined kinds of composition rather than by layering colors. The reason for this lies in the fact that every color has to be carefully inked into an allocated area of the plate, then wiped with different pads of scrim. This can be a demanding process and most etchers working in this method develop their own set of makeshift dabbers (e.g. card spatulas, small pieces of scrim or rag folded into dabbers, cotton wool buds etc.) enabling them to ink up even small, intricate areas of the plate. During wiping it is even more difficult to keep the different patches of color apart and often some blending of colors will occur in intersecting areas. In order to ensure that all bitten areas of the plate produce a rich deposit of color on the print, any shallow biting should be avoided and all lines, aquatints or open areas should be etched fairly deeply.
Even though the use of this dabber technique can yield quick and colorful prints from only a single plate, there are disadvantages. An a la poupee print is difficult to reproduce in editioning and in its pictorial appearance it often lacks the depth and complexity of either monochrome or multi plate etching.
Combined roll-up and intaglio printing
There are other ways in which a single plate can be inked with different colors. One way is for the plate to be inked up with one color – say a dark red – then scrim and tissue wiped as normal before a second colour – a yellow for example – is rolled over the plate with a hard roller in a single pass. This second color is a thin film of color which covers the surface but does not penetrate into the intaglio grooves. It is important for the ink to be thin and for the roller to be larger than the plate size in order to avoid any contamination of colors. After pulling a print the roller needs to be cleaned before the next inking takes place. This method can produce effective color etchings from smaller plates but has limited potential for large plates where the surface roll becomes more difficult to control. Sometimes localised areas of a large plate can be surface rolled in a particular color by using paper masks or stencils on the plate. This technique, however, produces sharp edges which may not suit all types of print.
Viscosity printing
The idea of printing different colors from different levels of an intaglio plate is pushed to the extreme in the technique of viscosity printing. Here, the etcher takes advantage of the fact that inks of a different viscosity can repel each other, and so can be used on the same plate without significant cross contamination. If three colors were to be used, the stiffest is inked into the very deep intaglio areas and all other areas thoroughly wiped. A very oily ink is now rolled over the surface with a hard roller. Finally, another stiffer ink can be applied to the intaglio areas of a medium depth by passing over the plate with a soft roller. In viscosity printing it usually takes a considerable amount of experimentation with all the variables, such as oils and inks of different viscosity, inking, scrim wiping and roll-up inking with hard and soft rollers, before the desired results are achieved. Very complex colored prints can be made from a single plate but the technical sophistication needed often makes the technique of multiple plate color printing seem a more practical option.
Colored paper
Apart from pure color intaglio techniques there are other ways to introduce color into an etching. One simple way is to use colored etching paper. Commercially produced colored papers are limited and it is more practical and economical to color your own sheets with waterproof ink or acrylic paint or by dyeing the paper pulp of handmade papers. Another approach (chine colle) is to incorporate pieces of colored paper into an etching. These colored shapes are pastedwith glue on the reverse and placed onto the inked up plate prior to printing. The shapes bond with the main sheet during the printing process and become an integral part of the intaglio composition.
Crossover techniques
An even greater number of creative possibilities open up when combining etching with other printmaking methods such as lithography or screenprinting. Screenprinting is ideal for quickly generating areas of flat color on a print instead of having to etch an aquatinted plate before printing it in intaglio. The acrylic based inks used in screenprinting dry as a porous surface which accept an etching overprint very well.
If crossover techniques are used, it is common practice to carryout the screenprinting or lithographic stages before the etching. This is due to the fact that the different kinds of ink bond better in this order and because the slightly raised printed image resulting from an intaglio plate can prevent a satisfactory ink deposit from a planar printing technique. It is important for the first stage of printing to be thoroughly dry before the paper can be soaked, blotted then printed in intaglio. Some paper surfaces may be too sensitive for conventional soaking but can be moistened by spraying from the back or placed between damp blotters. However, many kinds of papers have proven to be surprisingly resilient, even after having been subjected to numerous printings and the results can be of an excellent quality. The main problem with crossover techniques lies in matching up layers that have been printed dry with those that are printed wet. The simplest solution to this registration issue is bleed printing, where the image area covers the entire sheet of paper.