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Rotogravure (or gravure for short) is a type of
intaglio printing
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ea ...
process, which involves
engraving
Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it with a Burin (engraving), burin. The result may be a decorated object in itself, as when silver, gold, steel, or Glass engraving, glass ...
the image onto an image carrier. In gravure printing, the image is engraved onto a
cylinder
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an infin ...
because, like
offset printing
Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and then to the printing surface. When used in combination with the lithographic process, which is based on t ...
and
flexography
Flexography (often abbreviated to flexo) is a form of printing process which utilizes a flexible relief plate. It is essentially a modern version of letterpress, evolved with high speed rotary functionality, which can be used for printing on a ...
, it uses a
rotary printing press
A rotary printing press is a printing press in which the images to be printed are curved around a cylinder. Printing can be done on various substrates, including paper, cardboard, and plastic. Substrates can be sheet feed or unwound on a continuo ...
.
Once a staple of newspaper photo features, the rotogravure process is still used for commercial printing of magazines, postcards, and corrugated (cardboard) and other product packaging.
History and development
In the 19th century, a number of developments in photography allowed the production of photo-mechanical printing plates.
W H Fox Talbot mentions in 1852 the use of a textile in the photographic process to create half-tones in the printing plate.
A French patent in 1860 describes a reel-fed gravure press.
A collaboration between Klic and Fawcett in Lancaster resulted in the founding of the Rembrandt Intaglio Printing Company in 1895, which company produced art prints. In 1906 they marketed the first multi-colour gravure print.
In 1912 Messrs Bruckman in Munich produced proofs for Bavarian postage stamps which went into production in 1914. Also in 1912 newspaper supplements printed by reel-fed gravure were on sale in London and Berlin (''
The Illustrated London News
''The Illustrated London News'' appeared first on Saturday 14 May 1842, as the world's first illustrated weekly news magazine. Founded by Herbert Ingram, it appeared weekly until 1971, then less frequently thereafter, and ceased publication in ...
'' and ''Der Weltspiegel'').
Irving Berlin
Irving Berlin (born Israel Beilin; yi, ישראל ביילין; May 11, 1888 – September 22, 1989) was a Russian-American composer, songwriter and lyricist. His music forms a large part of the Great American Songbook.
Born in Imperial Russi ...
's song
"Easter Parade" specifically refers to this type of supplements in the lines "the photographers will snap us, and you'll find that you're in the rotogravure". And the song "
Hooray for Hollywood
"Hooray for Hollywood" is a popular song first featured in the 1937 movie ''Hollywood Hotel'', and which has since become (together with " That's Entertainment" and " There's No Business like Show Business") the staple soundtrack element of any Ac ...
" contains the line "…armed with photos from local rotos" referring to young actresses hoping to make it in the movie industry. In 1976, ex-Beatle
Ringo Starr
Sir Richard Starkey (born 7 July 1940), known professionally as Ringo Starr, is an English musician, singer, songwriter and actor who achieved international fame as the drummer for the Beatles. Starr occasionally sang lead vocals with the ...
released an album titled ''
Ringo's Rotogravure
''Ringo's Rotogravure'' is the fifth studio album by Ringo Starr, released in 1976. It was the last project to feature active involvement from all four former Beatles before John Lennon's murder in 1980, and the second of two projects following th ...
''.
In 1932 a
George Gallup
George Horace Gallup (November 18, 1901 – July 26, 1984) was an American pioneer of survey sampling techniques and inventor of the Gallup poll, a successful statistical method of survey sampling for measuring public opinion.
Life and career
...
"Survey of Reader Interest in Various Sections of Sunday Newspapers to Determine the Relative Value of Rotogravure as an Advertising Medium" found that these special rotogravures were the most widely read sections of the paper and that advertisements there were three times more likely to be seen by readers than in any other section.
Gravure is one of several printing techniques being actively used in the new field of
printed electronics
Printed electronics is a set of printing methods used to create electrical devices on various substrates. Printing typically uses common printing equipment suitable for defining patterns on material, such as screen printing, flexography, gravur ...
.
Process and components
In direct gravure printing, the ink is applied directly to the cylinder and from the cylinder it is transferred to the substrate. One printing unit consists of the following components:
* an engraved cylinder (also known as "gravure cylinder") whose circumference can differ according to the layout of the product being made.
* an ink fountain
* a
doctor blade
In printing the doctor blade (from ''ductor blade'') removes the excess ink from the smooth non-engraved portions of the anilox roll and the land areas of the cell walls. Doctor blades are also used in other printing and coating processes, such as ...
assembly
* an impression roller
* a dryer
For indirect gravure processes, the engraved cylinder transfers ink in the desired areas to a transfer roller, and the transfer roller transfers it to the substrate.
Engraved cylinder
The first step of Gravure is to create the cylinder with the engraved images that need to be printed: the engraving process will create on the cylinder surface the cells that will contain the ink in order to transfer it to the paper. Since the amount of ink contained in the cells corresponds to different colour intensities on the paper, the dimensions of the cells must be carefully set: deeper or larger cells will produce more intense colours whereas smaller cells will produce less intense ones. There are three methods of photoengraving that have been used for engraving of gravure cylinders, where the cell open size or the depth of cells can be uniform or variable:
Gravure cylinders are usually made of steel and plated with copper, though other materials, e.g. ceramics can also be used. The desired pattern is achieved by engraving with a laser or a diamond tool, or by chemical etching. If the cylinder is chemically etched, a resist (in the form of a negative image) is transferred to the cylinder before etching. The resist protects the non-image areas of the cylinder from the etchant. After etching, the resist is stripped off. The operation is analogous to the manufacture of printed circuit boards. Following engraving, the cylinder is proofed and tested, reworked if necessary, and then chrome plated.
Process
While the press is in operation, the engraved cylinder is partially immersed in the ink tray, filling the recessed cells. As the cylinder rotates, it draws excess ink onto its surface and into the cells. Acting as a
squeegee
A squeegee or squilgee is a tool with a flat, smooth rubber blade, used to remove or control the flow of liquid on a flat surface. It is used for cleaning and in printing.
The earliest written references to squeegees date from the mid-19th cent ...
, the doctor blade scrapes the cylinder before it makes contact with the paper, removing the excess ink from the non-printing (non-recessed) areas and leaving in the cells the right amount of ink required. The position of the blade relative to the nip is normally variable.
Next, the substrate gets sandwiched between the impression roller and the gravure cylinder: this is where the ink gets transferred from the recessed cells to the web. The purpose of the impression roller is to apply force, ensuring that the entire substrate is brought into contact with the gravure cylinder, which in turn ensures even and maximum coverage of the ink. Once in contact with the substrate, the ink's surface tension pulls (part of) the ink out of the cell and transfers it to the substrate.
Then the inked substrate goes through a dryer because it must be completely dry before going through the next color unit and accepting another coat of ink. A rotogravure printing press has one printing unit for each
color
Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associ ...
, typically
CMYK
The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation ''CMYK'' refers ...
or cyan, magenta, yellow and key (printing terminology for black), but the number of units varies depending on what colors are required to produce the final image.
Features
Because gravure is capable of transferring more ink to the paper than most other printing processes, it is noted for its remarkable density range (light to shadow) and hence is a process of choice for fine art and photography reproduction, though not typically as clean an image as that of
offset lithography
Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and then to the printing surface. When used in combination with the lithographic process, which is based on ...
. A shortcoming of gravure is that all images, including type and "solids," are actually printed as dots, and unless the ink and substrate combination is set up to allow solid areas to flow together, the screen pattern of these dots can be visible to the naked eye.
Gravure is an industrial printing process capable of consistent high quality printing. Since the Gravure printing process requires the creation of one cylinder for each colour of the final image, it is expensive for short runs and best suited for high volume printing. Typical uses include long-run magazines in excess of 1 million copies, mail order catalogs, consumer packaging, Sunday newspaper ad inserts, wallpaper and laminates for furniture where quality and consistency are desired. Another application area of gravure printing is in the flexible-packaging sector. A wide range of substrates such as polyethylene, polypropylene, polyester, BOPP, etc. can be printed in the gravure press. Gravure printing is one of the common processes used in the
converting
Converting companies are companies that specialize in modifying or combining raw materials such as polyesters, adhesives, silicone, adhesive tapes, foams, plastics, felts, rubbers, liners and metals, as well as other materials, to create new produ ...
industry.
Rotogravure presses for publication run at per second and more, with paper reel widths of over , enabling an eight-unit press to print about seven million four-color pages per hour.
The vast majority of gravure presses print on rolls (also known as
webs) of
paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed ...
or other substrates, rather than sheets. (Sheetfed gravure is a small, specialty market.) Rotary gravure presses are the fastest and widest presses in operation, printing everything from narrow labels to 12-foot-wide (3.66-meter-wide) rolls of vinyl flooring. For maximum efficiency, gravure presses operate at high speeds producing large diameter, wide rolls. These are then cut or slit down to the finished roll size on a
slitting
Roll slitting is a shearing operation that cuts a large roll of material into narrower rolls. There are two types of slitting: log slitting and rewind slitting. In log slitting the roll of material is treated as a whole (the 'log') and one or mo ...
machine or slitter rewinder. Additional operations may be in line with a gravure press, such as
saddle stitch
Bookbinding is the process of physically assembling a book of codex format from an ordered stack of ''signatures'', sheets of paper folded together into sections that are bound, along one edge, with a thick needle and strong thread. Cheaper, b ...
ing facilities for magazine or brochure work.
Advantages
Although the rotogravure printing process is not the most popular printing process used in flexible-packaging manufacturing, it does have the ability to print on thin film such as polyester, polypropylene, nylon, and polyethylene, which come in a wide range of thicknesses, commonly 10 to 30 micrometers.
Other appreciated features include:
* printing cylinders that can last through large-volume runs without the image degrading
* good quality image reproduction
* low per-unit costs running high volume production
Disadvantages
Shortcomings of the gravure printing process include:
* high start-up costs: hundreds of thousands of copies needed to make it profitable
*
rasterized
In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an Digital image, image described in a vector graphics format (shapes) and converting it into a raster image (a series of pixels, dots ...
lines and texts
* long lead time for cylinder preparation, which is offsite as the techniques used are so specialized
See also
*
Flexography
Flexography (often abbreviated to flexo) is a form of printing process which utilizes a flexible relief plate. It is essentially a modern version of letterpress, evolved with high speed rotary functionality, which can be used for printing on a ...
*
Offset printing
Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and then to the printing surface. When used in combination with the lithographic process, which is based on t ...
*
Photogravure
Photogravure (in French ''héliogravure'') is a process for printing photographs, also sometimes used for reproductive intaglio printmaking. It is a photo-mechanical process whereby a copper plate is grained (adding a pattern to the plate) and ...
*
Roll slitting
Roll slitting is a shearing operation that cuts a large roll of material into narrower rolls. There are two types of slitting: log slitting and rewind slitting. In log slitting the roll of material is treated as a whole (the 'log') and one or mo ...
*
Rotary printing press
A rotary printing press is a printing press in which the images to be printed are curved around a cylinder. Printing can be done on various substrates, including paper, cardboard, and plastic. Substrates can be sheet feed or unwound on a continuo ...
Notes
External links
European Rotogravure AssociationGravure Association of the AmericasHeliograph holding
{{Authority control
Engraving
Relief printing