Printing Raw Files

If you own a digital SLR (DSLR) camera - or a high-end compact digicam - you will find it provides two file format settings: JPEG and raw (often shown as RAW). When you shoot a JPEG image, the camera's image processor with adjust the contrast, sharpness, colour saturation and white balance BEFORE the image is saved to the memory card. When you shoot a raw image, this processing is deferred until the file is opened in a computer.

 

If you own a digital SLR (DSLR) camera - or a high-end compact digicam - you will find it provides two file format settings: JPEG and raw (often shown as RAW). When you shoot a JPEG image, the camera's image processor with adjust the contrast, sharpness, colour saturation and white balance BEFORE the image is saved to the memory card. When you shoot a raw image, this processing is deferred until the file is opened in a computer.

By definition, a raw file contains the data exactly as it is collected by the image sensor, along with image metadata (camera settings and other technical information), which can be viewed and used by the photographer - provided they have the right software. This is normally supplied with all cameras that support raw capture.

Most cameras that offer raw file capture will allow you to record both file types simultaneously. Some cameras compress raw files; others don't. Either way, raw files are usually larger than JPEG files because any compression that is applied is lossless so there's no loss of quality through compression artefacts. Raw images are usually saved as 12 or 14 bit files, depending on the camera's circuitry.

RAWplusJPEG

Most DSLR cameras allow users to shoot raw and JPEG images simultaneously and some models provide two raw file sizes plus several JPEG compression settings.

When a raw file is saved, the camera creates a header file containing all the camera settings, which are stored as metadata. The image itself is not changed; these settings are simply tagged onto the raw image data. They can be subsequently 'read' by software and used when the image is displayed on your computer screen. Since raw files can't be edited until they have been converted into a viewable format (usually JPEG or TIFF), most cameras also record a JPEG thumbnail so photographers can check shots.

Shooting raw files allows you to save all the information captured by the camera's sensor and then adjust critical settings (such as exposure, colour balance, contrast and sharpness) in editing software to recreate the image as you remember it. You can do this as often as you wish and save a variety of versions of an image. You can also re-convert the raw file years after it was taken and produce a completely new image. You can't do that with JPEGs.

Photographers who shoot raw files may also welcome applications that print them directly. However, the range of adjustments provided is usually less than you get with a dedicated editing application that supports raw file conversion. Furthermore, some proprietary applications are slow to support recently-released camera raw file formats. It is usually better to convert raw files and edit them in an application like Adobe Photoshop or Photoshop Elements before making prints.

However, it's important to understand that if you print a raw file without making any adjustments you will end up with an image that is virtually identical to a JPEG file that was shot simultaneously. The only difference will be that the raw file is larger and gives you much greater flexibility for editing.

Raw File Conversion|
All cameras that support raw file capture come with the necessary conversion software. Unfortunately, because raw file formats are proprietary, each camera manufacturer has its own format - and some even have different formats for different cameras in their range. So the software differs from one manufacturer to the next and often from one model to the next in a manufacturer's line-up.

Nikon-ViewNX
Olympus-Master

Two examples of the proprietary raw file conversion software supplied by different camera manufacturers. Note the limited range of editing adjustments provided.

The extent of printing support provided in bundled raw file converters also varies, with some providing a wider range of adjustments and easier user interface than others. However, none can offer as much flexibility as a dedicated image editor. Examples of the printing interfaces provided in two bundled raw file converters are shown above.

Nikon-ViewNX_print

Nikon's ViewNX provides very few adjustments in its printing interface.

Print-from-DPP

In contrast, Canon's Digital Photo Professional software interfaces effectively with the printer driver and allows users to select paper profiles, rendering intents and CMYK simulation settings.

Because the performance of bundled software varies between acceptable and frustratingly limited, many photographers prefer third-party applications. One of the best - and most popular - is Adobe Camera Raw, which is included in the latest versions of Photoshop and Photoshop Elements. This application supports virtually all DSLRs and raw-capable digicams on the market - although it may take several months for new models to be included and you may need to update your version of Camera Raw by visiting the Adobe website (www.adobe.com) when you buy a new camera.

Adobe-Camera-Raw

Adobe Camera Raw is the most popular raw file converter in current use. It provides a wide range of adjustments and supports conversion to 16-bit TIFF files.

Adobe Camera Raw is integrated into Adobe's Photoshop Lightroom 2 software, which is a complete workflow management tool. Apple produces a similar imaging platform, Aperture (now in version 2), which includes importing, organisation, viewing, editing and outputting facilities. Both applications come with integrated raw file support.

Popular third-party converters include Bibble (from www.bibblelabs.com) and Phase One's Capture One (www.phaseone.com/4/) and Silkypix Developer Studio (www.isl.co.jp/SILKYPIX/english/) which is bundled with some manufacturers' DSLR cameras. These products are available as trial downloads so you can try them and see which one suits your workflow best.

Direct Printing of Raw Files
In the past, photographers had to convert their raw images into JPEG or TIFF format before they could be printed. However, the growing popularity of the raw file format has encouraged several printer manufacturers to include facilities for printing raw files in some models in their printer range.

Some software developers have also released applications for printing raw files without the need for an editing interface. An example is Microsoft's RAW Image Thumbnailer and Viewer for Windows XP, which is available as a free download from the URL at the end of this chapter. There are also Photoshop plug-ins for several high-end desktop printers.

MS-RAW-Viewer

Microsoft's RAW Image Thumbnailer and Viewer for Windows XP provides links to a printer (circled in red) and an image editor (circled in green) as part of the user interface.

Microsoft has also added support for some raw file codecs in its Vista operating system. This allows supported raw files to be viewed in the Photo Gallery and perform most of the same editing tasks as they can with JPEGs. In general, supported raw files can be viewed, tagged, rated and printed. Windows Vista also exposes a set of APIs (application programming interfaces) that give other applications the same level of functionality by using the same RAW codec.

It's important to understand that a print of the raw file without any changes will look identical to a high resolution JPEG file captured at the same time. So, if you plan to make unedited prints, you might as well work with JPEG files. If you've shot with the RAW+JPEG setting on your camera, when you insert a memory card into a printer or connect it to the camera via a USB cable, only the JPEG images will be printable. The same applies when you take a memory card to a photolab (although Noritsu and Adobe Systems have recently signed an agreement that will allow Adobe DNG files to be printed on Noritsu equipment).

This doesn't mean you should stop using the RAW+JPEG setting; you can never tell when you might wish to delve a little deeper into an image file in order to correct one or more deficiencies and allow you to produce a print that matches the subject as you saw it when you took the shot.

The main problem with direct printing of raw files is the technological limitations associated with both the printer and the file conversion software. When looking at printers and software applications that can print raw files directly you should carefully consider the range of adjustments they offer. In most cases, these adjustments are limited to exposure and white balance.

The Microsoft RAW Image Thumbnailer and Viewer allows you to configure and run an editor (such as Nikon Capture NX or Adobe Photoshop) for each supported image type. This provides a much wider range of adjustments. Unfortunately, Microsoft has been tardy in supporting recently-released cameras (check the list of cameras supported before downloading it to ensure your images can be viewed).

Two notable professional workflow applications that include printing support are Apple's Aperture 2 and Adobe's Photoshop Lightroom 2.0, both of which allow users to produce high-quality prints, multi-image layouts and contact sheets. Aperture also provides facilities for designing customised books and creating websites within the application. It also contains a soft proofing facility that is similar to the one provided in Photoshop.

Aperture-book_2

Apple's Aperture 2 application provides facilities for creating customised books. Tutorials can be found on Apple's website.

Direct printing of raw files can be advantageous for photographers who want to make proof prints in the field. It allows them to see roughly how the shot will look when it's printed without having to go through the often time-consuming process of tweaking the raw image as it is converted and then editing it before making a print. But it's no substitute for printing from a powerful image editor.

Why Shoot Raw Files?
Because it's universal - and used by all digital cameras and related devices - JPEG is a convenient file format to use. Most snapshooters use nothing else and no point-and-shoot cameras offer raw or TIFF alternatives. But if you're serious about your photography, shooting raw files is so much better because:
1. Raw files are like digital negatives. Once you know how to process them - and have an appropriate file converter - you can extract the maximum possible image quality out of each photograph you shot.

2. Raw files allow you to extract much more image data to work with. When you shoot JPEGs, you are stuck with a bit depth of 8 - which is equivalent to 256 brightness levels. Shooting raw files gives you the option of converting them into 16-bit images which means the file has 65,536 levels of brightness. This gives you much greater scope for editing, particularly if you want to open up shadows or alter brightness in any significant way.

JPEG-image
JPEG-levels

The JPEG image above has been edited to recover some detail in the shadowed area in the foreground. In fact, very little improvement can be made without causing the sky to become posterised (which has already started to happen). In the attached graph, the white spaces show where image data has been lost. (This information can never be recovered.)

Raw-image
Raw-levels

The raw image above was converted into 16-bit TIFF format with Adobe Camera Raw software and then edited in Photoshop. As part of the file conversion, more detail was able to be revealed in the shadowed format and, because the image was converted into a much larger file, there was much more image data to work with so no vital information was lost in the editing process

3. Raw files don't have any white balance settings. The file is tagged with the camera's setting but the actual image data has not been changed. This lets you set any colour temperature you like without degrading the image. The same is true for contrast and sharpness adjustments - and also the image colour space.

However - if you don't enjoy working with images on your computer - or don't have time to process your images, JPEG is a satisfactory option and will be adequate for most applications (family snapshots, travel snaps, etc.). It is also preferable for images that will be shared online, either in emails or on websites. JPEG files are also smaller, which is advantageous if memory space is tight.

USEFUL URLs
The following websites provide additional information on the topics covered in this chapter.

www.microsoft.com/downloads/ will enable you to locate Microsoft RAW Image Thumbnailer and Viewer for Windows XP, which provides the ability to view, organise and print photos captured in RAW image formats from supported Canon and Nikon digital cameras.
www.photoshopuser.com/lightroom2/ provides a useful tutorial on printing through Lightroom 2.0.
www.apple.com/aperture/features/ outlines the features in Aperture 2 and provides links to tutorials on making prints and contact sheets and producing books.
www.photoreview.com.au for articles on digital printing and printer reviews.

 

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