Workflow for JPEG Photographers – Part I
by Brenda K. Hipsher – May 5th, 2010
by Joe Brady
With all of the discussion lately about the benefits of shooting a RAW workflow and the benefits of using the ColorChecker Passport, where does that leave our friends who primarily shoot JPEGs? While it is true that you need to have a RAW file to take advantage of custom camera profiles, there are many things you can do to optimize your JPEG images as well. Since a JPEG file has all of the camera settings including color space and white balance built into the file as soon as it is written to your storage media, it is critical that these items be correctly set before you start shooting. The idea here is to spend as little time as possible in front of the computer and have your images close to finished in camera. There are some pretty powerful edits you can do to JPEGs in software, but the less you do to the image, the more pristine the file will be – and that means a cleaner print with the best color.
Let’s start right at capture with exposure and white balance. Having a good exposure is very important for any image, but particularly so for JPEG images because you have less room for adjustments than with a RAW file. That said, if you overexpose any image enough, the data is gone, RAW or JPEG. Once all three channels hit 255, there is nothing left to recover. In the past, JPEG shooters were always told to underexpose to keep this from happening, but that has its own set of problems for two primary reasons. One – there is much more image data in the highlights than in the shadow parts of your images, so when you underexpose your highlights you lose a lot of color information. Two – underexposed images will start to get filled with color “grain” in shadow areas because the noise threshold of the sensor is catching up with the small amount of remaining image data.
If you are photographing a scene with lots of contrast in it, your camera’s meter can be fooled, so if this happens to you a lot, you might want to look into a handheld light meter. Since these meters measure the light falling on a subject instead of the light that is reflecting back, it can’t be fooled. We’ll talk about this more in future posts.
The moral to this part of the story is to be careful of your exposure, but get it right – don’t underexpose your JPEGs to play it safe.
The second decision in camera that JPEG shooters need to decide is which color space to choose. This will be determined by the use of the shots and how they are going to be printed. If you are a wedding/portrait photographer who is primarily sending your images out to a lab, I recommend sRGB as that is the color space closest to what most of the lab printers are using. By having a correctly exposed and correctly white balanced image (coming up next!), you can be sure that the print you get back will closely match your (calibrated and profiled) monitor.
If you are doing your own printing or capturing images that are going to be printed on a printing press in CMYK, then you should choose Adobe RGB. The advantage that Adobe RGB offers here is that it completely encompasses the CMYK space – something that sRGB doesn’t do. Both desktop inkjet printers and printing presses can easily print color outside sRGB – primarily in bright yellows and some blues and greens – so why throw out that color if you can print it? If you need your images to fulfill both purposes, then choose Adobe RGB as well and you can convert to sRGB when needed since Adobe RGB also completely encompasses sRGB.
Now that you have a correct exposure and have chosen your color space, you need to set a custom white balance in your camera. While it may be true that you have cameras settings called “Daylight”, “Cloudy”, “Tungsten”, etc., these are fixed temperatures that may or may not match the actual color temperature since each of these conditions may have a broad range. “Cloudy” for example may be set in your camera to mean 7800K on the Kelvin scale, but a cloudy day can easily approach 10,000K which is much bluer! When you set a custom white balance, you have the exact color temperature for the scene.
Now I realize that constantly setting custom white balances is not always practical. When this is the case, or when the light changes drastically from your last custom white balance, make sure to capture an image with a neutral reference (like the ColorChecker Passport shown above) so that you can white balance off this card. In any case, stay away from auto white balance! If you choose this setting, your camera will recalculate a white setting for every shot, so you can forget about matching color from image to image or even worse – trying to stitch together a panorama and getting the sky to match from stitch to stitch.
In my next post we’ll take a look at using Adobe Camera Raw for our JPEG images and see the advantages it can offer. Until then – keep shooting!