Printing

With super-sized prints all the rage in the fine-art world, especially photography, there are many ways to break out of the confines of a small page. For wide-format digital photo printing, each brand has its own maximum size. The Océ LightJet 430 can output a single image up to 50.5 X 120.5 inches, and the newer 500XL model can do 76 X 120.5 inches; the Durst Lambda 130 can make one seamless print the entire length of a paper roll, or 164 feet.

With inkjets, and this applies especially to imagemakers printing digital panoramas on roll paper or long cut sheets, the maximum printable area is dependent on three factors: the printer driver, the operating system, and the software application.

Driver/OS Limits: The printer driver and the operating system both interact to form the printer's maximum custom page size (this does not include margin area, which could make the maximum image size slightly smaller). For example, with the Epson Stylus Photo 2200, the maximum page length (Epson calls it the "maximum printable area") using the normal driver is 44 inches (129 inches with Windows 2000, Me, or XP). Using the CUPS Gimp-Print drivers as described earlier, the maximum is 1,200 inches! However, that's only in theory, because you may also run into the limits of the application you're using (see "Application Software Limits").

One way to exceed driver/OS limits is by using a PostScript RIP or application-direct export module. Once you've handed off the file to the RIP or export module, it takes over by rendering the page to a potentially wider range of maximum sizes, primarily through the action of tiling. Tiling means breaking up the image into smaller panels that overlap seamlessly, if desired.

An HP Designjet 5500ps (PostScript model) can print an image with a maximum length of200 inches. Take that same printer and replace the on-board driver with something like the PosterJet RIP, and the maximum size increases to 50 meters!

Application Software Limits: If you're using the standard printer driver, you may reach the limits of the software application before you reach the driver's maximum printable area. (This doesn't apply to RIPs, which trump the application software limits.) Photoshop, for example, used to have a limit of 30,000 pixels in any one dimension. Because of the way Epson drivers interface with Photoshop, the maximum page length for an Epson 2200 (to continue with the earlier example) was 41.67 inches, which was determined by taking the 30,000 pixel limit and dividing that by Epson's desktop "input resolution" of720 ppi. Now that Photoshop CS has increased its maximum to 300,000 pixels, the theoretical length limit of that Epson 2200 is 417 inches. However, that's still just theory since you may run into the driver limit before you reached that length.

One way around these application limits is either to use a PostScript RIP or to save the file to a page-layout or drawing program that does not have the pixel limit (but which may lead to other problems with color management; you just can't have it all sometimes!). QuarkXPress 4.x only goes up to a maximum page size of 48 inches. Illustrator 8.x/9.x goes up to 227 inches, and CorelDRAW 8.x/9.x can hit a whopping 1,800 inches. You are, however, still restricted by the printer's maximum custom page size—unless you do what I call application tiling.

This single image was output 50 feet long in one piece from an HP Designjet 5500 printer using the German-made PosterJet RIP. PosterJet has the ability to print a single image up to 50 meters in length!

Application Tiling: If you're not using a RIP, you can use application tiling to exceed the print device's maximum page-length limit and print in banner mode up to the application's maximum. This neat trick divides the image into smaller pieces that, when laid end-to-end, form one long image without breaks. Both Corel Draw 8.x/9.x and Adobe Illustrator 8.x/9.x allow you to do this. Figure 11.2 shows how Adobe Illustrator 8.01 would be set up to print a tall banner that's 44 inches wide and 227 inches tall on an Epson 10000 under an older OS.

A PostScript RIP, however, gives you even better control over tiling and may eliminate the need to use a page-layout or drawing program in the first place (unless you're creating your image that way).

Another way that application tiling can be done is by breaking up the image into individual tiles that are printed separately and physically reassembled by either butting or slightly overlapping the edges with tape or adhesive. The downside to this type of image tiling is that there will be visible seams.

This is how ceramic tile murals are done, and another good use of this technique is for making full-size mockups. This is also how intentional "collage art" images and superlarge images like billboards that are meant to be viewed at a distance are created.

Figure 11.2 At left is the Adobe Illustrator 8.01 Document Setup screen with Tile Full Pages checked in the View section. The right screen shows the custom page size (75.7 inches), created by dividing the banner size (227 inches) by 3 to yield 75.7, which is under the printers maximum.

Courtesy of Epson America, Inc.

Figure 11.2 At left is the Adobe Illustrator 8.01 Document Setup screen with Tile Full Pages checked in the View section. The right screen shows the custom page size (75.7 inches), created by dividing the banner size (227 inches) by 3 to yield 75.7, which is under the printers maximum.

Courtesy of Epson America, Inc.

Panoramas

Keeping in mind all the restrictions that limit the size of large prints, some of the most dramatic examples of digital printing are panoramas. There are many ways to accomplish this, usually either by manually blending digitally captured or scanned images (see Figure 11.3) or by using an automatic "stitcher" software program. Photoshop Elements and Photoshop CS both have a Photomerge function, and there are also many third-party software programs that seamlessly combine many separate images into one. Some of the variables that must be understood and conquered include: distortion, image equalization, rotation and horizon line-up, and many other factors. However, there is nothing like a long, seamless, horizontal (or vertical) panorama to show off the advantages of digital printing!

Figure 11.4 Photographer Ralph Cooksey-Talbott creates panoramic prints by manually combining a number of Nikon D-100 frames. Counter-clockwise from top: the final 120-MB Dry Creek Hilh image composed of six separate frames, a 72-inch version of the print coming out of an Epson 9600 printer, mounting the print with a back brace, and the finished print on the wall of the photographer's studio.

Figure 11.4 Photographer Ralph Cooksey-Talbott creates panoramic prints by manually combining a number of Nikon D-100 frames. Counter-clockwise from top: the final 120-MB Dry Creek Hilh image composed of six separate frames, a 72-inch version of the print coming out of an Epson 9600 printer, mounting the print with a back brace, and the finished print on the wall of the photographer's studio.

Courtesy of Cooksey-Talbott Gallery/www.cookseytalbottgaUery.com

Cheating Pixels

When you're stuck with a given resolution of an image, but you want to blow it up and print it big, Photoshop's Bicubic Resampling function does a fair job—up to a point. It creates interpolated pixels in an attempt to trick your eyes into seeing more detail than is actually there. However, the image soon begins to break down as you increase the enlargement. There are several software products that try to improve on the basic Photoshop interpolation method; each has its own group of believers. Here are three:

FM Stair Interpolation: Photographer Fred Miranda used to offer a Photoshop action (automated series of commands) that broke Photoshop's Bicubic interpolation method into small steps, which is why it was called Stair Interpolation or SI. At this writing, Miranda had replaced all the older versions with Stair Interpolation Pro, a Photoshop plugin (supporting 16-bit in CS) for PC and Mac that has options to interpolate images based on either paper size, pixel dimension, printer resolution, or scale. SI Pro is available via download (www.fredmiranda.com) for a nominal fee and works with all digital image files.

(Photographer Glenn Mitchell offers a free version of his TLR ImageResizer for Photoshop as an action set for enlarging in small increments. Downloadable from www.thelightsright.com)

Genuine Fractals: LizardTech's Genuine Fractals (GF) is a Photoshop plug-in that enlarges images using proprietary fractal technology. You first encode the image in GF's.STN format and save it with a choice of Lossless compression (2:1 savings) or Visually Lossless (5:1 savings). You then enlarge it: 150 percent, 250 percent, or more. The PrintPro version supports all Photoshop color modes including RGB, CMYK, and CIE-Lab, and it encodes and renders 8- and 16-bit images. How well GF works depends on the to-from file size and the type and quality of the image involved. For Windows and Mac.

Qimage: Qimage, the stand-alone image-editing and printing software, has nine different interpolation algorithms (including Lanczos, Vector, and Pyramid) to "res up" images. Many users feel that Qimage's interpolation methods are better than those used in most image editors for making large prints from small files.

Qimage developer Mike Chaney explains the differences among the main interpolation functions. "Most interpolation methods including Bicubic and Lanczos use a 'windowed' function to look at pixels in a square window, say 7 X 7 pixels. The interpolated pixel's value is computed using mathematical functions that apply a weight to each of the pixels in the window. The function itself is what determines how much weight each pixel contributes to the final interpolated (target) pixel, and therefore what the final image will look like. Bicubic usually produces smoother results, but less sharp, while the Lanczos function produces sharper results because it uses the mathematical sin function, which has a natural tendency to sharpen edges due to its repetitive or 'cycling' nature. Vector is a different kind of function that looks at geometric shapes produced by pixels and interpolates by looking at the target pixel's position inside a plane formed by several adjacent pixels in the source/original image. Pyramid is a complex extension of the vector algorithm. It basically refines the vector approach by considering many more complex shapes when creating the planes and doing the geometric placement of pixels.

"It's important to note that all interpolation methods have their pros and cons. Some are better for some types of images while others excel with different ones; for example, images with a lot of diagonal lines versus fine mesh patterns like screen doors versus 'random' details like sand on a beach. There is only so much that can be predicted through interpolation, and interpolation definitely has its limits, with each algorithm offering a different bias on the tradeoffs. When going beyond about 4x enlargements (which is a hefty stretch), you can smooth out the jaggies, but you'll never get even close to the amount of detail that you would have had if you were able to capture or create at that 4x size without interpolating!" (See Figure 11.4 to see how these main interpolation methods stack up in one sample image.)

Figure 11.4 Comparing interpolation methods: A—original with 1/4x downsample (inset) used as input to the other 400-percent upsamples), B-pixel resize (simple 400-percent zoom), C-Photoshop Bicubic Smoother, D-Lanczos, E-Vector, F-Pyramid.

Courtesy of Mike Chaney, author of Qimage www.ddisoftware.com/qimage

Figure 11.4 Comparing interpolation methods: A—original with 1/4x downsample (inset) used as input to the other 400-percent upsamples), B-pixel resize (simple 400-percent zoom), C-Photoshop Bicubic Smoother, D-Lanczos, E-Vector, F-Pyramid.

Courtesy of Mike Chaney, author of Qimage www.ddisoftware.com/qimage

The Secret World of Digital Black and White

There is an entire subculture of photographers doing super high-quality digital black-and-white imaging and printing. Following are some key techniques (mostly inkjet) from this hidden world.

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