Why Use DNG? - The DAM Book

form of the RAW image data, butit can also put “paperwork” intothis file. The IPTC and XMP fileinfo that lives in a DNG file canhold more data than you’re everlikely to need.Most importantly, however, theDNG can store a pretty good print.This is a preview that Camera Rawmakes from the photograph afteryou have adjusted the image settings.It’s essentially a JPEG file(sRGB, for those of you keepingscore at home) that can be pulledout of the DNG file and quicklyconverted for proofing purposessuch as email, Web galleries, orproof prints. Because Camera Rawenables such good adjustments,this embedded preview will be all Iexpect to need for 95 percent of myimage files.ALL TOGETHER NOWSo what does a DNG workflowlook like, and how does it help?For starters, I suggest you bringyour images into Photoshop CS2and apply some metadata—yourname and contact info, licenseinfo if appropriate, and anythingelse that applies to all the pictures.Then, rate the images for quality,using the Rating stars. After that,adjust the images in Camera Raw,paying most attention to the highest-ratedimages.Once the images have beenadjusted, convert them to DNGfiles. At this point, I archive thefiles and catalog them with iViewMediaPro. I can see the files iniView with my corrections applied,and can add to the metadata thatwas created in Photoshop.When I want to make proofs ofthe files, say, for a Web gallery, Ican have iView make it directlyfrom the embedded preview inthe DNG file, which is much fasterthan working from the RAW data.When I need to make master filesof selected images, I just openthe DNG file in Camera Raw andfurther refine my settings beforebringing the files into Photoshopfor final retouching, correction,and output.LONG-TERM ACCESSAll of the DNG benefitsdescribed thus far are largelyworkflow issues. Another importantaspect to consider are thelong-term access implications ofundocumented RAW file formats.Camera manufacturers havealready discontinued support forolder digital cameras. And changesin manufacturers’ software havewiped out settings for thousands ofimages painstakingly made.While DNG is not guaranteed tobe around forever, it has a betterchance than any particular individualcamera format currently available.As more photographers see itsbenefits, the number of DNG filesReprinted with permission from Studio Photography & Design, August 2005.www.infoimaging.comin existence will dwarf any othersingle format.I would expect this to be trueby the end of 2005. Other RAWconverters, such as Phase One’sC1 and Pixmantec’s RawShooterEssentials, already support orpromise to support DNG, so you’llhave multiple conversion optionsin the future. ❖Peter Krogh (www.peterkrogh.com) is a commercialand editorial photographer based inWashington, D.C. His book, The DAM Book: DigitalAsset Management for Photographers (www.theDAMbook.com), for O’Reilly Media, is set forSeptember publication. He is an Adobe AlphaTester and member of the ASMP board of directors,where he founded the Digital Standards andPractices Committee.