Working & Delivery File Formats
Working and delivery file formats need to work hand-in-hand. dpBestflow® recommends working in raw file format to the greatest extent possible. When it's time to deliver files, we recommend either TIFF or JPEG. Raw file delivery should only be considered if the person receiving the files is a trusted partner in the production pipeline.
There are two kinds of working files: original and derivative files. Original files are raw or JPEG files created by the camera. Derivative files are made from the originals. Both rendered and unrendered (raw) file formats can be used as working file formats. Raw file formats can only be used with PIE software, however. Rendered file formats can be used in both PIE and pixel editing software.
The scenario dpBestflow® recommends is to use raw file format for as much of your image editing as possible. If pixel editing is required in addition to raw image editing, the file formats of choice are TIFF and PSD. Of these two formats, TIFF is preferred since it's better supported outside of Photoshop and can provide every important function of PSD. TIFF doesn't require saving an additional flattened composite layer (maximize compatibility preference in PSD save dialog) to be visible in applications other than Photoshop, which include Media Pro, Photo Mechanic or Lightroom, for instance. This means that layered master files saved as PSD, with maximum compatibility on, will be larger than equivalent layered TIFF files.
Standard JPEG file format is not recommended as a working file format because its lossy compression will generate more and more compression artifacts with each save of an edited file. Simply opening and saving a JPEG does not trigger re-compression. However, altering even one pixel will. JPEGs that are saved at low compression/high quality settings of 10 or better in Photoshop do not visibly deteriorate for several saves, but eventually the re-saves will become noticeable.
Choosing the best file format for delivering digital image files requires good communication and collaboration with the persons receiving the files. There are the usual urban myths surrounding file types: that TIFF is somehow of a higher quality than the highest quality JPEG, for instance. However, it's important to explain that when delivering JPEGs, it's necessary to convert them to TIFF if more picture editing is going to be done in order to avoid the gradual deterioration that occurs when JPEGs are altered and then re-saved as JPEGs, triggering another round of lossy JPEG compression.
Read more in the File Delivery
Rendered delivery file formats are generally JPEG or TIFF. PSD is not recommended as a delivery format. PDF format can be used for image files although its main use is for files that contain both vector and raster data, such as those from page layout programs like InDesign and QuarkXPress. One feature of PDF is that it supports password protection although this feature has limited real world functionality. Some publishers and service bureaus specify EPS as a preferred format, but we recommend that you use this delivery format only if it is specifically requested. Some museums have standardized on JPEG 2000 due to its enhanced feature set which includes improved lossy as well as completely lossless compression. JPEG 2000 is not widely supported by Web browsers and is generally not used in the professional photographic, print, or design community.
JPEG is probably the most common delivery format since it takes up much less space on delivery media and uses less bandwidth for electronic delivery. JPEGs saved at the least compression or maximum quality – choose how you wish to express it – are visually indistinguishable from uncompressed TIFF files. Standard JPEG format has several important caveats when compared to TIFF. These caveats do not impact its usefulness as a delivery format as long as these features are understood. The fact that JPEG files can be very highly compressed means that it is easy to introduce visual and completely destructive image artifacts if the Photoshop save quality drops below 6 (on a sliding scale of 12). Different applications and even Photoshop Save For Web & Devices use different scales, which can be confusing. The best rule of thumb is not to go below the mid-point of any JPEG save scale if it can be avoided. Quality 8 on a scale of 12 is the minimum that should be used for delivery files. If you think there is any chance that delivery JPEGs will be altered and resaved as JPEGs, it is best to save at quality 12. It is a good plan to explain in a delivery memo or delivery readme file that JPEGs should be saved as TIFF or PSD files before any additional work is done on them. This will minimize compression artifacts on resave (and educate the uninformed) and allow the use of layers and other Photoshop features.
TIFF is probably the second most common delivery format after JPEG. Many design directors and publishers prefer it because it is an uncompressed format and doesn’t lose any quality with multiple saves. TIFF also has the advantage of supporting greater bit-depth and layers. The disadvantage of TIFF is that it is approximately ten times larger than JPEG. TIFF can be compressed both lossless (LZW) and lossy (ZIP, JPEG). However, LZW compression doesn’t result in much size saving (and may actually increase file size for 16-bit TIFFs). ZIP compression results in a slightly smaller file size than LZW, and JPEG compression comes very close to standard JPEG compression size. However, few TIFF readers, other than Photoshop and InDesign, read ZIP or JPEG compressed TIFF files. JPEG compression offers one advantage over simply saving as a JPEG and that is layers are preserved. JPEG compressed TIFFs do not support 16-bit depth. We recommend delivering compressed versions of TIFF only if they are specifically requested.
PSD, which is the native Photoshop file, is not recommended by dpBestflow® as a delivery format. It is often used for the creation of rendered master files since it supports the complete range of Photoshop features such as multiple layers, adjustment layers type layers, layer effects, paths, multiple channels, screening etc. PSD’s uniqueness as a working format has been somewhat diminished now that TIFF and PDF can save everything that can be saved in a PSD file. PSD files can be much larger than TIFF files if “maximize file compatibility” is turned on since this causes a flattened composite version of the file to be saved as a file within a file. Turning this feature off prevents some applications, Media Pro for instance, from showing a layered PSD file as an image file, which is not too useful if you catalog layered master files. We recommend that if PSD is not specifically requested, use either TIFF or JPEG for delivery.
Some organizations, such as DISC, which represents the publishing industry, have recommended DNG as a delivery file format. The attraction of DNG is that it is a standardized raw format and can be opened in all Adobe software (and an increasing number of other PIEware) no matter what camera it came from. In addition, DNG files can contain a rendered JPEG file, which gives a correct preview, (in Adobe software, many browsers and cataloging applications), preserving the photographer’s intentions for the image. On the other hand, DNG can be re-interpreted in supporting PIEware like any raw file. However, any digital image file can be re-interpreted and raw data is the best data to work with, even compared to 16-bit rendered files. DNG delivery may work well for photographers who want to shoot raw files, but don’t have the time, inclination, or facilities to do extensive post-production work.
Proprietary raw files
We do not recommend delivery of proprietary raw files unless they are being given to a trusted partner in the creative production pipeline. Raw files display differently in every PIEware no matter how the camera is set. This means that the interpretation of the images is entirely up to the choice of PIEware and how the PIEware is configured. For instance, Camera RAW can be set-up to auto adjust the main image controls: exposure, recovery, fill light, blacks, brightness, and contrast. The results may be good, or they may not be so good. The take-away is that the photographer’s intentions have clearly gone out the window. Some say that delivering raw files is the equivalent of handing over unprocessed film. We would suggest that understates the problem. Film is processed to a standard at least, whereas there is no standard for how raw files are processed. Delivering raw files is definitely dependent on the kindness of strangers; their knowledge base, their skill set and skill level and even taste with regards to how they think images should look.