A Photo Teacher |

Digital Photographic Printing

Posted in Lecture Materials by Paul Turounet on February 11, 2010

In considering the development of digital photographic output, it is important to understand the nature of the “print.” How digital output and the digital photographic print has developed is an outgrowth of the traditions and craft issues of conventional photographic printing in the darkroom, and both the commercial and fine-art printing press environments. Traditional (analog) printing is a mechanical process, whether in the darkroom or with printing presses, that uses a physical master or “matrix”, such as a negative or plate, to make repeatable and duplicate prints. Digital uses numbers (ones and zeros) to describe and quantify each sample point or “pixel” in terms of density and tone, which can be manipulated and transformed through digital printing into a normally viewed image.

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In the past, photographic prints and traditional fine-art printmaking have been considered as separate types of prints due to the practitioners of each (photographers, painters, printmakers) and the language (techniques) of each practice. There are photographic prints, black and white, color and alternative process, which utilize sensitized emulsions and surfaces to form the image on paper or other media. Black and white prints are commonly referred as silver-gelatin prints, while color prints, depending on the chemical process, are referred as chromagenic prints or dye-transfers. Alternative process prints include cyanotypes, albumen prints, platinum and palladium prints, as well as chemically toned prints. Traditional fine art prints or prints on paper, including relief prints, intaglio prints, lithography, screenprints and monoprints.

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Computer technology and digital printmaking brings together the possibilities of each of these artistic sensibilities and languages. In the past, making original prints, especially of a larger scale and in color, would be a costly process with varying degrees of artistic control and consistency. With continuing advances in digital print making, artists can now have greater technical control and consistency with increased cost efficiency and better storage flexibility.

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In getting involved in digital printing, the type of digital output desired (quality and cost) as well as whether to do the printing yourself or have a printmaking studio or printing service, such as a commercial photography lab, are important initial decisions. The advantages to self-printing include full artistic control though the learning curve and upfront investment pose challenges in the beginning. Using an outside printmaking studio or printing service provides access to knowledgeable professionals utilizing state-of-the-art technology and equipment and a lower initial investment cost. However, there is a loss of control and flexibility.

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Types of Digital Photographic Printing


Durst Lambda continuous tone printer (left) and Epson 9880 wide-format pigment printer (right)

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The digital image can be printed on conventional color photographic print materials, commonly referred to as digital chromagenic prints or “digital c-prints,” using continuous tone print writers such as the Durst Lambda or CSI Lightjet. Using three color-lasers (RGB) or light-emitting diodes (LED’s), these printers produce extremely high-resolution prints that are similar to conventional prints processed in a normal wet chemistry manner though their cost makes it possible for only commercial labs to own.

Inkjet | Pigment printers, both desktop and wide-format, provide the greatest flexibility in terms of printer types, inks, papers, sizes and third-party hardware and software. These printers use nozzles or print heads to spray millions of tiny droplets of ink onto a media surface.

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Inkjet | Pigment Printer Considerations

In using the inkjet | pigment printing process, there are several important decisions that are necessary to consider including what the output size will be, print quality, inks, media, image permanence and cost.

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The initial decision that needs to be determined will be the output size desired, as this will dictate the size printer necessary, whether it is a desktop-type printer or a wide-format printer. As a general principle, the larger the output size then the larger the printer must be and consequently, the higher the cost.  A desktop printer is considered anything that prints less than 24” wide, while wide-format printers typically utilize material on rolls and are capable of printing from 24” to 60” wide.

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A printer’s resolution, the number of colors used and the ink droplet size measure the print quality. The printing resolution, maximum dpi (dots per inch), determines the number of droplets produced in an image given dimensions. The difference between 1440 dpi and 4800 dpi is hardly noticeable to the eye in smaller-sized prints though utilizing higher printer resolutions is desired for larger-scale prints. The number of colors used will determine the subtle gradations of tone and description. The smaller the ink droplet size is, then the smoother the gradations of tone and the finer the detail will be in the print.

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Most inkjet printers utilized two types of inks, dye and pigment, which will determine the permanence of the print. Dye-based inks were the first inkjet inks used and provide excellent image quality and a gloss that is usually more uniform than with pigments.  However, dyes are more susceptible to light fading and are not considered archival. Pigment inks provide greater light and image stability. However, problems using some pigments may include metamerism, which is the shifting of colors under different types of lights, and choices in media that can be used. Because pigment inks sit on top of the paper when printed, glossy materials are not recommended as the ink does not adhere well or creates “bronzing” where the image will have sheen.

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The media is the material used in the inkjet printer, including coated and uncoated papers, canvas, and transparency transfer materials. In general, paper is the most common material printed on and there are two types of paper.  Uncoated papers, those used in traditional printmaking environments such as cotton rag paper and watercolor paper, can be used with inkjet printers, though dye-based inks are preferred.  Such papers can potentially clog the ink nozzles as well as cause damage to the printer due to their thickness. Coated papers are similar to uncoated papers, but have a receptor coating added to the paper’s surface to better receive the ink.   In terms of coated papers, there are photo papers, which tend to have a luster, glossy or matte finish and fine-art | photo rag papers, which resemble traditional photographic papers as well as watercolor papers.

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Considerations in Preparation of Digital Photographic Printing

Some important considerations in preparing for digital printmaking is the color space being used to optimize and print the image, color management within the monitor to printer workspace, and printer profiles.

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Color Space


The color space is the environment in which the subjective nature of color is quantified, including the hue, saturation and brightness of color. There are a number of common color spaces from which to work in such as LAB, RGB, and CMYK.  One of the important and distinguishing characteristics with each color space is the color gamut, which defines the entire range of possible colors possible in that system.

The LAB color space most closely represents how the human eye sees color and is the largest of the common color spaces. RGB is the most dominant color space for digital artists and is the default space for most digital cameras and scanners. It is the preferred color space for digital inkjet printing. There are several sub-varieties of RGB working spaces, including Adobe RGB (1998) and sRGB.  Adobe RGB (1998) is the largest of the default RGB color working spaces and covers the gamut range of common CMYK devices, including inkjet printers. sRGB is generally set-up as the default working space in Photoshop and other hardware/software settings, though it is mainly used for working with web images and not digital output.  CMYK is the standard color space for the commercial printing industry.

In general, work with master files in an RGB color space, preferably Adobe RGB (1998), and repurpose the file in CMYK as needed.

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Color Management

The color gamuts of all scanners, cameras, monitors and printers are different. Monitors use the additive color system (RGB), while printers use the subtractive color system (CMYK). Color management is a way to smooth out the color gamuts of these various devices and processes to ensure consistent color throughout the digital workflow. There are three places to do color management: (1) print driver level, (2) application level and (3) operating system level.   In developing a color management system, it is preferable to use  color management software to calibrate cameras|scanners, monitors and printers.

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Printer Profiles

Printer profiles characterize how a given printer will function with a given set of inks and media. It’s not the printer that’s profiled, but rather the combination of printer resolution, and driver settings, ink and paper. There are generic profiles that are preloaded in the print driver as well as customized profiles from third-party providers such as ink and paper manufacturers. A RIP (Raster Image Processor) is a more sophisticated software tool, providing even greater control over color management, ink configuration and with grayscale images.

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Basic Digital Photographic Printing

In preparing the image for digital printing, it will be necessary to perform some final optimization steps.  Such optimizations may include image sharpening and image resizing.

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Unsharp Mask Filter

Prior to printing, additional image sharpness may be desired and there are a variety of techniques in Photoshop for improving image sharpness.  One common technique is using the Unsharp Mask by clicking on Filter > Sharpen > Unsharp Mask.  It is recommended that the image sharpening be done only during printing after flattening the optimized file and saving it as to a second print-only file if desired.  It is important to that you have the optimized file (with adjustment layers) saved for future use.

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When using the Unsharp Mask filter, it will be necessary to evaluate the image in Actual Pixels or at 100%. On the duplicate layer for the Unsharp Mask, turn down the opacity.

The Amount setting controls the intensity of the sharpening applied. The higher the percentage (up to 500%), the greater the sharpening effect will be, typically a digital capture being around 50% to 100% and inkjet output being from 120% to 200%. The Radius setting controls the width of the sharpening effect with a setting of .5 to .1 for capture sharpening and 1.0 to 2.0 for inkjet output. The Threshold setting controls which pixels will be sharpened based on how much the pixels to be sharpened deviate in brightness from their neighbors. At lower settings more or all pixels are sharpened including areas of smooth continuous tone, such as settings between 0 and 10.

In practice, first set the Amount to a really high percentage (500 % is recommended). Second, set the Radius, watching for where texture and detail become brittle. Third, reduce the Amount as little as possible. Fourth, set the Threshold in a conservative manner. Fifth, and finally, click on Edit > Fade and check the Mode to Luminosity. This will limit the effect of the sharpening to dark and light values, leaving color unaffected.

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Page Set-Up

Before setting up the digital printing workflow, it will be necessary to insure the image has been sized for the print size. In addition, it will be necessary to flatten the layers.

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To begin the printing workflow, click on File > Page Setup. It will be necessary to set the formatting to a specific printer, determine the paper size, orientation and scale.  In the Grossmont Digital Photography Lab, the printers are identified as 20-104-4880-Left and 20-104-4880-Right.

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Print

Click on Image to Enlarge

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Second, proceed to click on File > Print. This will allow for the color to be configured and handled. With the Document selected under Color Management, proceed to the Color Handling, which will give three options, including Let Printer Determine Colors, Let Photoshop Determine Colors and No Color Management.

With Let Photoshop Determine Colors, there will be greater control and a more consistent workflow that utilizes custom printer profiles can be achieved. Under the Printer Profile, a preloaded profile or customized profile can be selected in relationship to the type of printer, ink, and media combination being used.

Under the Rendering Intent, there is Perceptual, Saturation, Relative Colorimetric and Absolute Colorimetric. In setting the Rendering Intent to Relative Colorimetric, the white of the source color is compared to that of the destination color space and shifts all colors accordingly. Relative Colorimetric preserves more of the original colors in an image than Perceptual. Black Point Compensation should be checked to obtain true blacks in the image.

It is important to select the proper Printer Profile.  In the Grossmont Digital Photography Lab, the following Printer Profiles are used:

LEFT 1030372_Epson Premium Luster.icc

RIGHT 1030372_Epson Premium Luster.icc

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LEFT_Ilford Gold Fiber Silk.icc

RIGHT_Ilford Gold Fiber Silk.icc

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Print Settings


Before the image can finally be printed, it will be necessary to set the parameters of how the image is printed, including the number of copies to be printed, print settings and color management.

There are Presets for the Epson Premium Luster and Ilford Gold Fiber Silk papers.

In general, A – letter sized prints of 8.5” x 11” and larger sized prints, the SuperPhoto – 1440 dpi will be work.

The printer’s color management should be turned-off as this is being handled by Photoshop.

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Ready to Print

Once all of the parameters have been set, the image can now be printed. It will be necessary to load the media into the cut-sheet tray of the printer. Insure that the coated side is face down. Depending on the thickness of the material, it may be necessary to use the straight-through manual feed option.

Just like photographic prints made in the darkroom, it is necessary to allow inkjet prints to be dried prior to handling, from a few minutes to hours. Once the print has dried, a protective coating, such as a lacquer-based spray (PremierArt Print Shield), can be applied to further protect the print from moisture, UV light exposure, atmospheric contaminants, and scuffing.

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