As suggested by the name, planographic printing includes all those techniques in which the ink is neither pressed down into the paper nor raised above the surface of the paper, but lies in a flat plane on the surface. In planographic techniques the pressure of the press, if indeed there is a press at all, isgenerally much lighter than relief or intaglio printing.
Various Planographic printing techniques are...

Lithography
Invented in 1798, lithography is perhaps best known from the prints of the 1890’s by artists like Bonnard and Toulouse-Lautrec. The process is based on the mutual antipathy of oil and water. To make a lithograph, the artist uses an oily or greasy medium such as crayon or tusche (an oily liquid wash) to draw a composition on a flat, ground stone. The surface of the stone is then flooded with water, which is repelled by the greasy areas and stay only where the drawing isn’t. Printer’s ink (oily) is applied to the stone with a roller and it, in turn, sticks only to the greasy section, as the water repels it elsewhere. The stone is then covered with a sheet of paper and run through the press to create the print.

Though lithography literally means, "stone drawing" in modern times the expensive and unwieldy limestone block has often been replaced by a grained metal plate, in which case the print is sometimes called a zincography. The stone or plate, it should be noted, is not etched or engraved in any way but simply acts as a solid surface for the antipathetic actions of oil and water. A transfer lithograph, in French parlance, an autographie, is one in which the original design was drawn on a paper made especially for the process and then mechanically (not photographically) transferred to the stone or plate.

A photo-lithography is generally a reproduction and not an original print. Colour lithographs are made through the use of several stones or plates to separate the colours and printing the same sheet of paper with each of them in turn. A lithotint, in traditional usage and as made by J. A. M. Whistler, is a lithograph in which the image is created on the stone with a brush and oil-based ink in the manner of a wash drawing. It is otherwise handled and printed exactly like crayon lithography.

Screen-printing
Screenprinting does not require a printing press. This technique was made famous in the 1960’s, when artists such as Andy Warhol exploited its bold, commercial look to make Pop icons. To make a screenprint, an image that has been cut out of paper or fabric is attached to a piece of tautly stretched mesh. Paint is then forced through the mesh – or screen – onto a sheet of paper beneath it by means of a squeegee. The uncovered areas of the screen will, of course, allow the paint to pass through, while the areas covered by the compositional shapes will not. For works with more than one colour, a separate screen is required for each colour. The technique is often referred to as serigraphy, a term coined to distinguish between commercial and artistic screenprinting.

Cliché-Verre
Cliché-Verre, or glass print, is different from every other print technique in that the image on the paper is not produced with ink but with light-sensitive chemicals. The basic cliché-verre is made by coating a clear glass plate with collodion or printer’s ink and drawing a design through that coating with a stylus. A sheet of photo-sensitised paper is then placed under it and the assemblage exposed to light (usually sunlight). The image will be received onto the photo paper, exactly in the way that a photographic print is made from a negative, and the image is then chemically fixed. A more sophisticated technique involves painting the design on the glass, the varying densities of the ink or paint appearing on the final print as varying shades of white to black. The technique is proto-photographic, but not reproductive since there is no camera involved. It was especially popular with Corot, Daubigny and other Barbizon artists.

Digital /Iris /Giclee prints Digital Prints:
Iris Prints/Giclee. Iris prints are created by printing computer-generated images on a large-scale ink jet printer manufactured by IRIS. The ink is dispersed by a sophisticated print head in a fine mist of minute droplets in order to deliver a continuous tone image. Iris prints can be made using highly saturated, archival, water-based ink on a wide range of materials, from traditional art papers to fabrics and wood veneers. Epson print images are also computer generated and realized. Epson printers use pigment-based archival ink rather than water-based inks. The Epson process is better suited to project that involve a combination of printing techniques, especially those that involve the immersion of once-printed paper in water as a step in the printing process. In addition to the materials that can be printed on with Iris printers, the Epson printers can accommodate rigid materials such as copper plates or cardboard.

Monotype/Monoprint
As their names imply, monotypes and monoprints (the words are often used interchangeably but shouldn't be) are prints that have an edition of one, though sometimes a second, weaker impression can be taken from the matrix. A monotype is made by drawing a design in printing ink on any smooth surface, then covering that matrix with a sheet of paper and passing it through a press. The resulting image will be an exact reverse of the original drawing, but relatively flatter because of the pressure of the press. A monoprint is made by taking an already etched and inked plate and adding to the composition by manipulating additional ink on the surface of the plate. This produces an impression different in appearance from a conventionally printed impression from the same plate.
Since it is virtually impossible to manipulate the additional ink twice the same way, every monoprint impression will be different from every other one. Degas made monotypes; Whistler made monoprints.

Pochoir
Pochoir is a direct method of hand colouring through a stencil. The stencil itself is usually knife cut from thin coated paper, paperboard, plastic or metal and the ink or paint is applied with a brush through the stencil to the paper beneath, Multi-coloured pochoirs are produced with multiple stencils, and the technique has often been used to add colours to black and white lithographs.