Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Adobe Photoshop > Technique

This chapter is from the book

Adobe DNG Converter

Adobe DNG Converter is a handy standalone application that converts camera vendors' proprietary raw images to Adobe's new DNG format. It's entirely up to you whether or not you choose to use it—Camera Raw, Bridge, and Photoshop are equally happy with proprietary raw files or DNGs—but the following discussion may help you decide. My personal bias is that the advantages of DNG outweigh any disadvantages, and using DNG sends camera vendors an important message about the future of digital photography, but it is a bias. The choice is really up to you.

To DNG or Not to DNG

Adobe developed the DNG format in response to a very real concern over the longevity of digital raw captures. One of the major problems with camera vendors' proprietary raw formats is that they're undocumented—only the camera vendor knows for sure what they contain. I bear no ill will to any camera vendor, and I hope that they'll all be around for decades to come, stimulating competition and innovation, but it's not beyond the bounds of possibility that one of today's vendors may not be around five, ten, or fifty years hence. The question then becomes, what happens to all the images locked up in a defunct vendor's proprietary raw format?

Archival format

A kindly third-party vendor may decide to take on the work of reverse-engineering the format to continue support (and let's all give a huge vote of thanks to Thomas Knoll for the enormous amount of work he's already done in decoding all those proprietary raw formats), but absent that, you'll be stuck with old, non-upgradable software at best, and gigabytes of unreadable data at worst.

The DNG format provides insurance against obsolescence because unlike proprietary raw formats, it's an open, documented format whose file spec is readily available, so any reasonably talented programmer can build a converter that reads DNG files without any reverse engineering, even if Adobe should, perish the thought, no longer be in business. So unlike the proprietary raw formats, DNG can fairly lay claim to being an archival format.

The first release of Adobe DNG Converter had one potential flaw—it stripped any private metadata that it couldn't understand. While the only things that could possibly use this metadata were the vendors' proprietary raw converters, few of us like the idea of losing something in the translation. Subsequent releases of Adobe DNG Converter address this problem by letting you embed a bit-for-bit copy of the proprietary raw file that can be extracted at any time, at the cost of a somewhat larger file size.

Metadata friendly

A related issue is that, because proprietary raw files are undocumented, Adobe treats them as read-only files, since writing to them runs the risk of overwriting potentially useful data. So when you add metadata to an image, it gets stored in either a sidecar .xmp file or in one or another application's database.

In contrast, since DNG is a documented file format that's designed to hold metadata, it's safe to write metadata directly into the DNG file, eliminating the need for sidecar files and thus simplifying the workflow. As with proprietary raw formats, the actual image data in the DNG never gets changed. If you work for a client who demands that you submit raw files (as does National Geographic, for example), it's safer to hand off a DNG file with all metadata embedded than it is to submit a proprietary raw along with a sidecar file that may get discarded.

Third party support

As an open format, DNG is much easier for third parties to support than are the proprietary raw formats. Asset managers and cataloging applications that support DNG automatically gain support for every camera supported by Camera Raw. Thumbnails and previews can be stored directly in the image file so applications don't have to spend time building their own, and there's no possibility of the image losing its metadata because the metadata is right in the image file.

More specialized applications are also beginning to support DNG. For example, DxO Labs' DxO Optics Pro, which provides sophisticated corrections for distortions introduced by many common lenses, now offers the ability to write the corrected images as DNG files, so you can apply lens corrections, write them to DNG files, then process the images in Camera Raw.

Ultimately, the proliferation of proprietary raw formats serves no one's interest, not even that of the camera vendors (although at the time of writing, many of them still seem to need convincing on this point). The DNG spec is flexible enough to let those vendors who insist on doing so put private, secret metadata tags into their images, while ensuring that those images will still be readable by any DNG-compliant converter.

Downsides

The major disadvantage to using DNG is that DNG files will likely not be readable by your camera vendor's proprietary converter. If you typically use Camera Raw on some images and a proprietary converter on others, it's fairly inconvenient to extract the proprietary raws from the DNG file, so you'll want to either keep versions of the images in both formats, or forego the advantages of DNG. If you don't use the camera vendor's software, this disadvantage doesn't apply.

The second disadvantage is that when you choose the "bulletproof" option that embeds the entire proprietary raw file in the DNG, your files will be somewhat larger than the original proprietary raws.

My own solution has been to archive one copy of each image as DNG-with-raw-embedded to long-term storage, while using the smaller, losslessly compressed DNG option for my working files. An equally viable option is to archive a copy of the original raws (bearing in mind that they'll only be readable as long as the camera vendor chooses to support them) while using DNG for working files.

Using Adobe DNG Converter

Adobe DNG Converter is a very simple application. It's not the only way to convert proprietary raws to DNG—you can save DNGs right out of Camera Raw—but it's a very convenient way to process large numbers of images into DNG format. See Figure 3-3.

03fig03.jpg

Figure 3-3 Adobe DNG Converter

The main screen lets you set the following options:

  • You can choose a source folder full of raw images for conversion, and optionally include subfolders.
  • You can choose a destination, either in the same location as the source raw files or in a new folder, with the option to preserve the subfolder organization.
  • You can rename the converted images with the same options as the Batch Rename command in Photoshop and Bridge.
  • If you have previously saved DNG files with the original raw file embedded, you can extract the original raw file.

To change the conversion options, click the Preferences button to open the Preferences screen—see Figure 3-4.

03fig04.jpg

Figure 3-4 Adobe DNG Converter Preferences

The conversion options are likewise very straightforward.

  • Compression (lossless) applies lossless conversion. Unless you own stock in a hard drive vendor, I can't think of a reason to turn this off.
  • Preserve Raw Image preserves the raw pixel data in its original mosaic format. Use this option if you want to be able to take advantage of all Camera Raw's features. You can convert a DNG saved this way to a linear DNG, but not vice versa.
  • Convert to Linear Image saves a demosaiced version of the image. This option is mostly useful if you want to use a DNG-compliant raw converter other than Camera Raw on images from a camera with a mosaic pattern that isn't supported by the raw converter. Linear DNGs are much larger than mosaic-format ones, so if you're thinking you can save processing time by converting to linear DNG, think again—any savings in processing time are offset by the extra time needed to read the data.
  • Embed Original Raw File embeds a bit-for-bit copy of the original raw file in the DNG, from which it can be extracted at any time. I use this option for my archived images just in case I need to retrieve the original raw files at some future date, but I turn it off for my working files to save space, because embedding the original raw file increases the file size considerably.

When you click Convert, Adobe DNG Converter goes to work converting the selected raw files to DNG format using the options specified in Preferences, and displays a status window that shows the progress of the conversions—see Figure 3-5.

03fig05.jpg

Figure 3-5 Adobe DNG Converter status window

To extract the original raw files from DNGs with the original raw embedded, click Extract, which opens the Extract Originals dialog box. Here you can specify source and destination folders for the extraction. When you click Extract, Adobe DNG Converter extracts the original raw files from the DNGs. See Figure 3-6.

03fig06.jpg

Figure 3-6 Extract Originals

At the time of writing, the main benefit offered by DNG is the elimination of sidecar files, and it's entirely up to you whether or not you want to use it, though it's very easy to do so. There's no particular urgency to adopting DNG, but if you care about the longevity of your images, I do recommend archiving at least one copy of each image in DNG format, and if you want to be able to retrieve the original raw files, embed the original raw in the DNG. That way, you've preserved the raw image in a format that's documented and hence is likely to readable as long as humans can still read.

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email ask@peachpit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.peachpit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020