by Q.-Tuan Luong for the Large Format Page
Summary: an overview of the digital printers able of high-quality color output in large format, including continuous-tone printers and inkjet printers, as of July 2005.
While in B&W, there is still a place for the traditional darkroom despite recent advances in digital printing, most of fine art printing in color is nowadays done digitally. The tools in the B&W darkroom always gave its practioners a tremendous amount of control. With the exception of the dye-transfer process, it wasn't until the advent of digital workflows that color photographers gained access to equally powerful controls. However, dye transfer is extremely time-consuming, expensive, and difficult. Availability of materials is problematic, since the few remaining experts rely on stockpiles of discontinued supplies. The tactile and visual qualities of the medium have always played a large role in B&W photography, and there is a considerable range of possibilities. In color photography, the practical output choices are limited between type-C prints and Ilfochrome/Cibachrome. Digital printing not only includes those options, but adds quite a few of its own.
By far, the most commonly used papers are type-C (for printing from negatives) processed in RA-4 chemistry. Of all the type-C papers, the preferred medium is Fuji Crystal Archive, that has the best longevity rating of any color photographic paper. Crystal Archive has an estimated longevity rating of 60 years, whereas the best previous photographic paper, Cibachrome/Ilfochrome, had a longevity rating of 35 years. The sharpness and color is excellent, with very deep blacks. Crystal Archive comes in three varieties, Semi-Gloss, Glossy, and Super Glossy. The glossy papers look more deep and "three-dimensional", however they are also more fragile. The surface is less tolerant to scratches and fingerprints than the semi-glossy paper. Super Glossy is a polyester-based surface like Ilfochrome/Cibachrome which has a metallic, mirror-like finish. It is also possible to print on Ilfochrome/Cibachrome, but this is rarely done.
Printers include the Cymbolic Sciences Lightjet, Durst Lambda, and ZBE Chromira. Since its introduction, in 1996, the Lightjet has emerged as the printer of choice for fine-art printing. The Lambda is more often used for commercial printing. I was told by a tech at a Custom Color Lab in Palo Alto (incidently, the rise of digital forced that lab out of business in 2002) that the reason why the Lightjet is used for fine art printing is that it is such a "bear" that it would be too inefficient for commercial printing. We did a series of tests with one of my images that I had printed on the Lightjet by another lab. With the settings that he used, his Lambda prints were noticeably softer. Both of those printers use lasers, and cost about $200,000. The more recent Chromira uses LEDs, and costs "only" around $60,000. This made it possible for fine-art labs such as West Coast Imaging or LaserLight to acquire one, whereas before they would send out for Lightjets. The LEDs are low-power, unlike lasers, which makes maintainance and calibration easier. The Chromira is said to produce prints at least as good as the Lightjet. Because of those high costs, those printers are exclusively operated by labs. There are probably less than a thousand Lightjets installed worldwide.
The maximum printing size of the most commonly installed Lightjet printers is 48x96 inches (Reed Photo Imaging of Denver can print up to 48x120 inches). The less common Lightjet 500XL (in the US: Laumont, ColorEdge, Duggal, Ferrari Color, in Germany: Grieger) is currently the largest continuous tone printer. It prints up to 72x120 inches. Lambda's are limited to 50 inch wide. Earlier Chromiras were limited to 30 inch wide. The newest generation can print up to 50 inch wide.
Because those printers have very high-quality interpolation algorithms, and because of the nature of photographic paper, where there is a bit of diffusion, excellent results can be obtained with 200DPI files, although the native resolution is 300DPI.
It is necessary that the lab provides you with the ICC profiles of their printer on each type of medium they use, since this is the only way you'd get a precisely matched color. A good lab also linearizes their printer daily in order to provide consistent results.
The costs of materials for those printers is the lowest of any, at around $0.30 per square foot. However, labs have to recoup the price of the initial investment for the printer. Competitive good labs charge around $12 per square foot.
A large variety of papers can be used. Some of those papers try to mimic the apparency of traditional photographic papers, with RC surfaces, semi-glossy and glossy finish, while others have a matte finish which is unique to the inkjet process. Interesting heavy and thick fine-art matte paper of refined appearance, as well as watercolor and canvas can be used with the inkjets. With such papers, the print will look very different from a traditional photograph. This look can be a bit "flat" for an unframed print. Longevity rating is excellent, exceeding those of photographic paper based on accelerated fading tests. It must be noted that those tests failed to predict rapid fading of some ink/paper combinations in the past.
Those printers were the first large format inkjet printers yielding a combination of quality color, metamerism problems well controlled, and longevity (at least as good as the Crystal Archive papers), thanks to their "Ultrachrome" pigmented inks. Before that, you had the choice between dye-based inks that yielded excellent color and dense blacks, but were not archival (some of the prints began to fade just after a few years), and pigment-based inks that were archival, but had a reduced color gamut (range of colors that can be reproduced), in particular in the reds colors, and serious metamerism. Metamerism refers to the fact that colors would shift when viewed under different light conditions. So you could produce a print that was perfect looking in your studio under 5000K lighting, but if the print was viewed under more common tungsten or halogen lights, it would take an ugly magenta cast.
The gamut (range of colors that can be reproduced accurately) is slightly wider than the gamut of the Lightjet, in particular in the blues and oranges. However, the blacks are not as deep as those obtained on the Lightjet, which makes for prints that look more "flat". The Epson papers are not as nice to the touch as photographic papers. They are also more easily damaged, for instance a water drop could damage a print. However, once the print is framed, most of the advantages of the Lightjet are reduced.
Many people avoid printing on glossy paper (such as Epson Premium Glossy Photo Paper) with the Epson Ultrachrome inks, because of a problem known as "bronzing", or "gloss differential". Gloss differential is what happens when light is directly reflected towards the viewer from off of the print. The result is darkened, or "bronzed," reflections where ink has been laid, and full reflection (blown-out highlights) where little to no ink has been laid. Because different colors can have different "gloss", under certain viewing conditions (generally at an angle), the print will not look uniform, but rather will have a patchy appearance. In general, bronzing is not a real issue once the print is framed. Semi-glossy papers (such as Epson Premium Luster Photo Paper) can exhibit this problem to a lesser degree. Matte papers do not suffer from bronzing. Bronzing can be mitigated by applying a coating to the print with such products as Lyson Print Guard, and Premier Art Print Shield, that make the reflection more uniform.
Another potential problem is "out-gassing" with glossy and semi-glossy papers. In order to avoid nozzle clogging, some humectant chemicals that are very slowly evaporating are added to the inks. When printing on photographic-like papers (glossy and semi-glossy coated surfaces), those chemicals are not absorbed by the paper. They'll still be on the print long after the water has gone and the print "feels" dry. As they evaporate over time, they can cause fogging in the inside of the glass when the print is framed. With uncoated paper, this is not a problem, since the humectants can be absorbed by the paper. In order to prevent outgassing, one must cure all the prints for a few days before framing. The best way to do it is, after letting the print dry for about a hour, is to lay absorbent paper (Chris Jordan uses news print paper that comes in huge rolls of a thousand feet long for $50, while Joseph Holmes uses Light Impressions Renaissance non-buffered archival paper) totally flat against the print with no air in-between for at least 24 hours, preferably with pressure. Prints can be stacked and interleaved with absorbent paper in order to achieve that. The paper acts like a sponge and draws out the gases from the inks much faster than they would escape if just exposed to air. The paper will go wavy as the solvent evaporates. You keep interleaving until the paper is no longer wavy.
Setting up the 7600/9600/10600 can be tricky. In order to get the widest color gamut from the 7600/9600/10600, it is necessary to use the "no color adjustment setting", and profile the printer. Creating a good profile can be very difficult, since the grey-scale raw output in that setting is highly non-linear and suffers from complex color casts. Fortunately, the 7600/9600/10600 incorporates an automatic closed-loop calibration technology which is so good that any two printers provide basically the exact same output. It is therefore possible to use a profile created by someone else for their printer on your printer. Bill Atkinson created excellent profiles for his own use, and makes them available for free.
The native resolution of the Epson printers is 360DPI. When using a file with not enough pixels, it is in general better to interpolate the file in photoshop. Feeding the Epson with less than 240DPI results in inferior prints on photographic paper. However, I have once produced a large print on canvas at 175DPI and have been pleasantly surprised at the results.
In 2004, HP released a new set of inks and matching paper, which is a "swellable medium" that expends to receive the inks, and then contracts to protect them. They are available in the affordable ($1300) Designjet 130 printer, that can print up to 24 inch. This made it possible for them to use dye-based inks while achieving a longevity rating comparable to Epson pigmented inks.
The appearance of the Designjet 130 prints compares very favorably with the Epson prints. In particular, Charles Cramer (View Camera Magazine, March/April 2005) observed that the blacks obtained by the 130 were the blackest that he has ever seen in his career, better than the highly regarded color Dye Transfers, or even Selenium-toned Ilford FB B&W silver gelatin papers. He rates the density of the blacks in the following order, starting from the best blacks: HP Designjet 130, FB B&W silver gelatin, Dye transfer, Lightjet, Ilfochrome, Epson 9600. This observation has been corroborated by several reviewers.
According to Joseph Holmes beta-testing report, this printer represents a significant advance. The differential gloss problem ("bronzing") is much reduced, the output much more neutral and linear, and the blacks considerably improved, in particular on glossy papers. They would fall in between Dye transfer and Lightjet. The Ultrachrome K3 inks have a slightly larger gammut, and an even better longevity rating than the Ultrachrome inks. They are also said to produce outstanding black and white prints.
Inkjet printers have dramatically improved. In many metrics, they have surpassed continuous tone printers. They can create prints that have a similar look as traditional photographs as well as prints that have a unique look on matte, fine art, and canvas surfaces. However, the prints still look more like ink on paper (because it is what they are) than traditional photographs, where the color is embodied in the paper, giving it a more three-dimensional and glowing appearance.
The printing costs (ink and paper) vary between $1 and $2 per square foot. See the tables for Epson Ultrachrome printers (the cost and printing costs for the next-generation Epson printers 9800/7800 are expected to be the same) and HP printers.
This, combined with the relatively affordable costs of the printers, is the main advantage of inkjet printers. They allow the photographer to own his printer. Having in-house printing capabilities, besides improving efficiency, let you have instant and low cost feedback, and fine-tune prints in a way that would not be practical when you have to order prints from a lab. The cost of consumables is much less than the cost of ordering a print from a lab, which in the long run makes the printer pay for itself if you print enough.