Editing photography
Working with RAW
January 21, 2012 2:36 PM ADT
Photography postprocessing: Working with RAW images
If you happen to own a DSLR or a high-end point-and-shoot and you're still shooting with JPEG then your photos are missing out on a potential quality boost. I say potential because RAW images are exactly that, the raw data from you camera; it has not been processed into a final image yet.
Using RAW is handy because a JPEG image gets processed inside the camera using algorithms that promote speed over quality. The image processor also doesn't know when one photo needs a contrast boost, or when another needs more exposure. By processing it on your computer later you can get the best possible quality - and in some cases save an overexposed or underexposed image.
RAW doesn’t mean you should not put time into finding the right exposure for your photo though. If there is no data - such as a fully blown-out highlight - nothing can recreate it.
I'm going to be using Adobe Camera Raw (ACR) for this article. Unfortunately it only works if you have Photoshop, but there are many other good free RAW image processors out there such as RawTherapee (http://rawtherapee.com/). Below left is a photo loaded in ACR, but unchanged. To the right is a photo after playing with some values (scroll down for a larger version).
When you first load a photo ACR has a number of sliders/values you can change on the right below a histogram. For the most part you should start with the temperature section and work your way down.
Temperature and tint are both related to the colour of light. Adjust these until your photo is as neutral as possible. You can always choose auto or another pre-defined setting, but I prefer to use the original as a reference while I set it manually.
After temperature comes luminosity. ACR has a built in "auto" feature which tries to guess the luminosity values. I do not recommend using this setting for the final copy, but it can be handy as a reference. There is no single setting that works for every photo, just move the sliders and decide what looks best to you.
The exposure slider changes luminosity levels linearly across the whole photo by up to +/- 4 stops.
Recovery will darken your more extreme highlights. In some rare cases it can make your photo look flat if turned too high.
Fill light will brighten your shadows, but can cause noise to be more visible in those shadows.
Blacks will set how deep your shadows are. In most cases I recommend leaving it around 5.
Brightness is a less extreme version of exposure. It somewhat preserves highlights while increasing/decreasing luminosity linearly across the rest of the image.
Contrast increases the contrast between highlights and shadows across the whole photo. Personally I tend to leave this around 20-30 and use other techniques to change contrast (more on that next week). (contrast high/low)
Clarity is one of my favourite features in ACR and also can't be found outside Adobe products (that I know of). Moving the slider to your right will increase local contrast (different than the above contrast setting) and can really make details pop out at you. Moving the slider to the left will soften your photo.
Vibrance and saturation will affect the colour of your photo, at lower values your photo will almost look like it was shot in black and white.
Now you may have noticed by now that I've only been talking about the basics tab in ACR. ACR can also do curves, sharpness, straightening, cropping, colour and lens correction, and much more. Excluding colour and lens correction I don't often use these features as they are all included in Photoshop, where some of which are more powerful.
Before
After
All photos posted were taken by the author unless stated otherwise. Originals can usually be found on isock.deviantart.com
1 comment
Juan Carlos Gesto on Jan 21, 2012 at 3:05pm
Courius article
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