Over the past few years Internet chat rooms that cover photography have often discussed whether digital images are acceptable for magazine reproduction or turning into large, fine art prints. It seems certain overseas travel and ‘fine art’ magazines are still refusing to accept digital images for publication on claims their quality isn’t good enough. Australian publications are, usually, happy to accept digital image files and many even prefer them because they integrate more readily into the production workflow. But only files that are ‘good enough’ will be accepted.
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Over the past few years Internet chat rooms that cover photography have often discussed whether digital images are acceptable for magazine reproduction or turning into large, fine art prints. It seems certain overseas travel and ‘fine art’ magazines are still refusing to accept digital images for publication on claims their quality isn’t good enough. Australian publications are, usually, happy to accept digital image files and many even prefer them because they integrate more readily into the production workflow. But only files that are ‘good enough’ will be accepted. Until recently, defining what was ‘good enough’ was a subjective exercise, depending on individual publishers’ whims. But now, a committee of leading international publishers has agreed upon a set of standards for publishable digital photographs. The Digital Image Submission Criteria (DISC) committee contains members from leading magazine publishers (including Business Week, CMP Media, Condøƒ © Nast Publications, G & J USA Publishing, Hachette Filipacchi Media US, Hearst, Newsweek, Parade Magazine, PriMedia, and Time Inc.) and imaging companies, such as Eastman Kodak, Fujifilm, Creo, NEC and Quad Photo. Their guidelines for photographers can be found on the committee’s website (www.disc-info.org) and cover image sizes, file formats, file standards and metadata. They can be downloaded in PDF format by anybody who plans to submit digital image files to publishers of all types (the file is only 132 KB in size, making it available to those with dial-up Internet connections). DISC Specifications The DISC specifications have been divided into three categories to match the end use for the image files. Category A provides the highest possible quality (300dpi and 150 line screen) and is suitable for high-quality glossy publications or fine art prints. Category B (250dpi and 125 or 133 line screen) is for weekly magazines on lower quality paper while Category C (200dpi and 100 line screen) is suitable for publication on newsprint in daily newspapers or local weekly papers. DISC provides the following instructions for photographers: 1) First determine your Category; if you do not know which one to use, then select Category A (since this is the highest possible quality). 2) Reference the size of the reproduction, move across the chart to determine the proper resolution settings from your digital camera. To keep things simple, it is always preferable to use the maximum pixel resolution your camera has to offer. 3) Adjust your camera parameters so that the COLORSPACE (aka ColorMode or ColorMatrix) is set for “ADOBE RGB (1998)” as sRGB or CMYK files will not be accepted. Leave all colour management to the prepress professionals since they do this job best. 4) When saving your digital images, set to JPEG “High Quality 8”, this is a numerical value used from Photoshop 7 (some camera parameters refer to this as JPEG FINE). 5) Metadata must be completed using the IPTC international standard. The IPTC header information is filled out to describe your digital images, such as photo credit, copyright information, caption, etc. A look at DISC’s Category A data (an abridged version of which is reproduced on this page) shows their specifications are a little conservative. However, they provide an excellent – and reliable – estimate of the maximum print size you should expect to produce from any digital camera or scanned image file.
Photographers may find these guidelines useful for determining the optimum sizes for inkjet printing – with some reservations. Caution is required with files that have been upsized by interpolation, as some methods can actually increase pixellation, while others can compromise the sharpness and contrast of the printed image (see the illustrations on these pages). Certain up-sizing algorithms work better on some image types than others, so a degree of experimentation will be required to match the original file’s parameters with the best up-sizing method. Check out the special upsizing feature on pages 58-60 in the last issue of Photo ReviewAustralia. Depending on the nature of the original image, it may be possible to resample an image file to increase its pixel count. However, photographers are advised to proceed cautiously and conservatively – and always work on a copy of the image, preserving the original as a master file. Upsizing cannot add picture information that wasn’t captured in the original shot; it can only add in extra pixels, based on existing pixels. As a result, images generally become softer as they are enlarged because the amount of information per pixel is reduced. Software-based Sharpening Some photographers use the sharpening and contrast tools in their software applications to correct for the loss of contrast and sharpness in up-sampled images. This strategy is only partially successful. Photoshop’s Sharpen and Sharpen More filters are fairly crude because they work by increasing the tonal difference between adjacent pixels. The Unsharp Mask filter is much more powerful as it allows you to limit the sharpening effect to just the pixels that differ from surrounding pixels by a threshold that you can set. You can also customise the amount of sharpening applied and set the width of the band of pixels involved in the sharpening. (We caution against using more than about 150% of sharpening over a radius in excess of 2 pixels). Used conservatively, these filters can counteract some of the downsides of interpolation-based up-sampling. However, they can never match the result you will obtain by shooting with the correct resolution settings in the first place. FEATURED LINK: www.epson.com.au for all your printing needs.
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