METROPOSTCARD.COM GUIDE TO PRINTING TECHNIQUES 4
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Tricolor and Process Printing


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TRANSITIONAL PROCESS PRINTING


During the 1940’s and 50’s a battle for market dominance raged in postcard publishing between those that produced highly stylized linens and those making natural color cards based on Kodachrome film. The quality of heatset inks and drying chambers had also improved in the post war years. The solvents inks contained could be quickly vaporized, drying their resin base before it could be absorbed into the paper or spread. Printing postcards on linen card stock was no longer a necessity, though it remained in use as a familiar stylistic element that was now subject to the whims of public taste. Neither method produced realistic looking cards but both had their adherents. Linens remained the most common postcards in distribution following the Second World War. Most were based more on a retouches hand than the actual photograph they started from. The public seemed to love these high color images so when the duller photochromes started to show up, many publishers just thought this a fad. While early photochomes promised natural color, they could not quite yet deliver on it. The public’s however had a growing fascination with technology since the 1930’s, which kept many interested in this technique’s prospects. This interest would only continue to grow as photochrome cards grew closer to their ideal.

Graphic Arts Photography
In the earliest forms of photomechanical reproduction original negatives were simply contact printed onto a photosensitive printing substrate. This was easily done in postcard production because many film negatives were already manufactured in postcard size, and older glass plates were even larger so they just needed to be cropped. Some mediums required the negative to be converted into a positive transparency before exposure to a substrate. Duplicates negatives were also made so that the same image could be transferred onto multiple substrates, thus speeding up production on large press runs. These activities marked the beginning of graphic arts photography that was based on technical needs rather than creativity. As the need for halftone prints grew rapidly in the 1890’s, a greater demand was placed on this new type of photography.

The appearance of color on a postcard had once indicated the handiwork of a retoucher. Whether copied from a work of art or a black & white photograph, color separations were created by hand either by directly manipulating the image on the substrate or more often by blackening out specific parts of the negative before its exposure to the printing plate. Though specialized process cameras were developed in the 1930’s to aid in the production of halftones, they would only become an essential tool in color separation after 1938 when a reliable sources of photographic color was found. Before photographing an image a halftone filter is place in front of the camera’s lens. These filters first took the form of glass crossline screens that could reproduce an image in dots of varying sizes or same size dots in different densities of area. These screens were eventually replaced with easier to handle high contrast film sheets. If an image is to be printed in color, then four photographs are taken of it through color filters that will be used to create plates that will each print one CYMK process color. Most presses had the capacity to print large sheets of paper so multiple postcards were printed at the same time from one plate. This required film strippers to gather all the needed negatives or transparencies and tape them together (stripping) into layout sheets (flats) in the proper arrangement that would allow the photosensitized printing plate to be exposed only once.

Postcard

Film Stripping: On this French Postcard a film stripper is carefully piecing negatives together on a larger transparency so that they can be exposed to a single photosensitive plate at one time, and still be perfectly aligned for cutting apart after printing. Time and money can be saved by printing many cards at one time (gang printing), and this became an industry standard.


Unlike most cameras, those used in the graphic arts were designed with special lenses to produce high resolution film images from two-dimensional images such as linear drawings (line art), text, or photographs with minimal distortion. Many shops had large horizontal process cameras (darkroom camera) built into walls between lit rooms that held the copy work, and darkrooms where the light sensitive film sheets were handled. Most early separations for postcards were made on the smaller vertical camera (gallery camera) where the lens faces downward toward a copy board to which the image is secured. When using vertical cameras the whole copying process had to take place within a darkroom, and their smaller size also put limits on how far they could reduce an image. Eventually the greater convenience of the horizontal camera made it the industry standard.

The production of quality transparencies eventually grew so complex that many printers outsourced this prepress work to specialists. By the 1980’s, advances in digital technology caused most of these procedures to be replaced, which created the need for a whole new type of specialist. Images are now digitally scanned for improved accuracy, and halftones can be projected directly onto film with a laser. More modern electronic page makeup systems now allow images to be transferred directly onto a plate or a sheet of paper from a computer without the need for film.

Photograph

Darkroom Camera: This horizontal copy camera sits on a track so the distance between it and the frame holding the image to be copied (out of view) can be easily adjusted. Attached to it are bellows so it can extend outwards from the darkroom behind it from where it is controlled.


Positive Negative
To transfer a photograph to a printing plate, either negatives or positive transparencies are employed depending on the medium. Each medium had its own requirements as to the exact type of film needed and how many times a negative had to be made into a positive or visa versa. Since most photomechanical printing processes involve gelatin emulsions some generalizations can be made from how it happens to sit on a particular substrate. Light hardens photosensitive gelatin, so after exposure any covered areas can be washed off from the substrate on which it lays. In intaglio printing this washing will expose the bare plate to an acid etch that will incise it by dissolving the metal away. Since the ink will be held in these deep incised wells, they must correspond to a positive transparency. In lithography it is the areas of the stone or plate left exposed to light that will be chemically treated so that they will have the ability to attract and absorb water. This in turn makes them repel rolled ink leaving the paper white, so the image must correspond to a negative. If the original image is in the wrong format it has to be re-shot into as a transparency (reverse negative) or a negative. Color film was only produced as transparencies until the 1940’s when workable print film was introduced that provided negatives. Black & white glass plates and film traditionally produced negatives until reversal film became available in the early 20th century.

Manipulated Process Printing
The look of linen postcards did not remain static while in competition with photochromes. Publishers began relying less on retouchers once color could actually be separated from Kodachrome film. Many hybrids were produced by publishers trying to have the best of both worlds, but these cards often look disjointed and cannot be enjoyed for their photo-realistic quality or their stylization as both aspects tend to come into conflict with each other. As time went on many linens began to rely so heavily on photomechanical color separation that their distinction with photochromes began to blur. Even the distinction between early and modern photochromes are not easy to define. This was particularly true between the time process colors were developed in 1934 and Kodachrome transparencies were perfected in 1938. During the 1930’s there was a growing optimism surrounding technology that despite trying times it would make life better for all. The public’s interest in natural color photography was in part due to this general attitude, and the term natural color was widely used as a marketing ploy to help attract customers. Some publishers even printed the words Natural Color onto the back of their linens to cash in on the growing demand for these types of cards when in fact they provided nothing of the sort. Such terms may have entered into common vocabulary but they did not have any legal definition.

Postcard

Linen: This linen postcard from 1943 states that it has been made in Natural Color while it is obvious that its hues have been laid out in flat blocks by a retoucher. This line block is not even a process print but a tinted halftone.



Postcard

Linen: While the background on this linen postcard published in the 1940ís shows some of the typical heavy handed signs of retouching, the trellis in the foreground has been rendered in a more realistic way as if directly based on a photograph. The combination however renders a rather awkward looking image.



Postcard

Linen: This late linen postcard goes out of its way to let the buyer know it was made from a Kodachrome transparency by printing the fact right onto its border. It seems however to have picked up on little of the film’s color subtleties though the color that film provided at this time left something to be desired. Note the blurry car in the foreground that has not been removed by a retoucher like it would normally be on a typical linen card. Was this to help give the image a more photo-like appearance?


Not all early process prints made efforts to render natural color. Publishers were keenly aware of the public’s interest in the bright colors that accurate color separation from color photographs just did not provide. A wide range of cards would be produced that come close to looking like photochromes, but they still typically involve a fair amount of retouching when it comes to color. Even while process colors (CYMK) were now commonly used as a standard, there were still some postcards being printed with red, yellow, and blue as their primary tricolor palette.

Postcard

Linen: This late linen postcard from 1954 was printed in typical CYM halftones but the black key is an aberration. It has been drawn in by hand as solid lines for the figures and as dots with the aid of a paper tint within the landscape. Naturalistic color was put aside in favor of stylistic graphic design.



Postcard

Process Print: Most color illustrations reproduced through process printing no longer relied on retouchers to make color separations but were simply photographed with color filters to prepare the four CYMK plates. While each of the color dot patterns on this postcards are rotated by 30-degrees to form rosettes, no halftones were used. It is entirely composed of lithographic dots created through shading mediums; either benday or paper tints. This clearly shows that shading mediums could be used for far more than fill in work.



Postcard

Process Print: The colors on this postcard from 1952 have been so obviously enhanced by a retoucher that it is difficult to make out the original source. Adding to the confusion is its untypical palette of red, yellow, blue, and black.



Postcard

Process Print: On this postcard from 1950 cyan, yellow, and red were used as the three process colors printed in the standard halftone rotation. Magenta has been used to replace black on the key plate, which has not printed darkly but as a ghostly medium violet-grey. This choice not only flattens out the image, it turns into the darkest color where it overprints the red upsetting the overall tonal scheme.



Postcard

Process Prints: Both of these halftone postcards employ the same palette, which is almost CYMK but a redder hue is used in place of magenta. The card above from 1941 is more heavily retouched to create near solid colors while the card below states that it has been made from a natural color photograph. Neither has very realistic colors but they are each designed to attract a target audience; one looking for a traditional bright palette as found on linen cards, and the other by those intrigued with the possibilities to be found in new color photography.

Postcard


Postcard

Process Gravure: Although this postcard has most of the characteristics of a photochrome, the colors appear a bit too pure suggesting retouch work. This appearance has been enhanced by it being printed in rotogravure instead of the usual offset lithography, which has create hues that are very rich but given the card an overall soft look. While a good number of these types of cards were printed, especially in Europe, they did not become the dominant model for process printing.


One of the trademarks of photochrome postcards are their glossy finish. This not only simulated the high gloss photo papers that had become popular, this overprinting of varnish created more vibrant colors. Nearly all pigments whether it be in paint or ink have more color saturation when they are wet. The transparent medium they sit in has a tendency to trap light, which in turn allows for more interaction with the colorants while reducing surface scattering. Plainly speaking more light is reflected back into the eye to read as color. While postcards cannot be sold wet they can be varnished, and this transparent medium creates a similar effect.

Postcard

Process Print: This postcard was printed in a CYMK palette but it was not varnished. Its matte finish lowers color saturation and lightens all of its tonal values.



Postcard

Tinted Halftones: Both of these tinted halftones postcards from the late 1950’s use the popular intermediary palette of medium red, yellow, and a light blue that are not quite CYM but far removed from RYB. They demonstrate that even at this late date retouchers were still choosing the entire palette for postcards rather than separating them from color photographs. Some chrome cards were so heavily retouched that they could easily be mistaken for linen cards if not for the smooth glossy paper they are printed on.

Postcard




PHOTOCHROMES


The 1936 release of Kodachrome, as a fine grain, multi layered transparency film with reliable color would prove to be an extraordinary event. While it would take a couple more years to work out problems with its chemistry and only come into full production after World War Two, it provided for the first time an easy mechanical way to make separations for printing based on natural color. Most color postcards up to this time had their origins in monochromatic photography. Multiple negatives had been made from a single black &' white transparency, which were then retouched to hold only one specific color before being photomechanically transferred onto a printing plate. Sometimes multiple substrates were exposed to a single negative and then the retoucher would add his handiwork to each plate or polish out areas of unwanted color. While trichromatic photochomes had been made since the 1870’s, early examples did not achieve the same level of natural color as modern chromes due to the limited hues available as inks. Their commercial success had also been limited by the complicated methods of extracting color from black & white film. Even when process colors were first developed in 1934, the best tricolor prints made from them only approximated natural color.

Most printers up to this point had added color in by hand, but as skillful as any hand might be it still is not capable of rendering all the minute subtleties captured through photography. While these nuances are often too small to even describe, the eye picks them up immediately. A drawing can always be discerned from a photo, and drawn in color never comes anything close to that captured on film. Since Kodachrome comes very close to capturing natural color, attempts to mimic this coloration by hand were no longer necessary. Extracting color from a single negative also made the process less expensive and time consuming to execute. Postcards going forward would not only be printed in natural color, the imagery they carried would appear more real.

Postcard

Tinted Halftones: This early matte photochrome postcard published by the Union Oil Company in the 1940’s is printed through lithography in CYMK process colors. While the card’s coloration is not totally natural. It feels as if it is based on a color photograph. In the detail below we can see the tight frequency of dots used to keep the image sharp.

Postcard Detail

The first Kodachromes produced were far from perfect; colors were often unsaturated and contrast was poor. Even so, postcard images began being based on this film in 1936. After the film underwent major changes in 1939, many more printers began switched to process printing but wartime shortages would hamper production until the late 1940’s. Once the method of producing photochromes was well established, it became the most economical way to create postcards and it grew to dominate the printing industry. Even the reproductions of illustrations that did not necessarily require the use of process printing were usually manufactured in this manner out of expediency. As time passed the color accuracy and saturation of Kodachrome improved along with the printing techniques that employed it to create more natural color.

Postcard

Photochrome: Not all early postcards based on Kodachrome were printed in the same way. This matte photochrome from 1943 was printed with RYB primaries in line block. The absence of a black plate has prevented the darks from rising above a muddy grey. Despite the somewhat realistic application of color it still leaves much to be desired.


The term photochrome had been used since the 1870’s to refer to any printed photomechanical image that employed the tricolor process. Though today we refer to modern photochromes as those postcards printed in offset lithography with the process colors developed in 1934, we need to remember that there are some variations to this model that achieved the same effect. Likewise even though Kodachrome was instrumental in creating the modern photochrome all sorts of film have since been used in their production. One must be careful with names for photochrome has been used too carelessly over the years often being attributed to similar looking but distinctly different products. Process printed photochromes have often been confused with postcards printed with the screenless Swiss photochrom process (Aäc), at least in name, even though they are two polar techniques. Some American publishers have also used the term photochrome for their photochrom-like cards, which has only added to the confusion. Today most people refer to process printed photochromes simply as chromes.

Postcard

Photochrome: It is fallacy to believe that all photochromes are based on Kodachrome transparency film.This postcard published by Fischgrund in the late 1950’s is based on Kodacolor print film, yet otherwise it has still been printed in offset lithography with the typical CYMK pallet of a process print.


While photochromes were able to capture colors that were very close to those found in color photography, it must be remembered that even the best photograph is a distortion of reality. The dyes used in Kodachrome were good at capturing bright reds but not the subtitles of green. Other films used different dyes that rendered similar images but in a different gamut. In any case the exact rendition of a color is impossible because of all the steps that remove the final product from the original. This is but one element in the inherent flaws of this process that is easiest to see in the reproduction of art work where the point of reference is not only constant but in front of you. Many photochrome postcards suffer from strange color shifts as matching ink to exact wavelengths of light is still better in theory than in practice. Postcards are not printed with pure color; they are printed with color ink that is a chemical mixture containing impurities. Different colors can and have been used as primaries in printing, but the combination of any can only produce a limited color gamut. The limited number of process colors used in printing make it very susceptible to unwanted color shifts. If any single ink is distributed unevenly during printing it will throw off the carefully worked out color balance and create a red, green, or blue cast.

Postcard

Photochrome: This photochrome from 1954 does not capture a real scene but was made from a photograph of an illustration. While it has some of the same mannered characteristics of a linen card, it does not come from the hand of the retoucher but from the original artwork, which has been rendered faithfully.



Postcard

Photochromes: Despite the general idea that the natural color on photochromes is derived from the real world, these cards continued to be retouched. The sky on the postcard above from the late 1960’s is printed in pure cyan without any color mixing to make it appear brighter. The color isolation of skies became a standard practice with chromes. Colors have also been segregated on the card below so there is no mixing of dots where hues are meant to be exaggerated. Both cards also exhibit a strong color cast toward red, but it is impossible to know if this was intentional.

Postcard


Postcard

Photochrome: As the photochrome card was perfected, its ability to render natural color outpaced all processes that came before it but it still was far from perfect. If any one of the CYM colors becomes too dominant as the magenta does in the postcard above, an unnatural color cast is created. Even on cards where the overall color distribution is good, color cast remained a common problem. This was much less noticeable on cards whose subject matter incorporated heightened natural color as seen below.

Postcard


Postcard

Photochrome: The plate that printed both of these postcards in 1989 was not only made from the same transparency, both cards were printed in the same press run. Somewhere along their production the cyan ink stopped printing at the proper density required to render the correct gamut. This was most likely caused by an insufficient supply of ink being transferred from the palette of the press, which allowed the other printed colors to dominate the balance and create a cast.

Postcard





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