Friday, December 28, 2007

Reader Mail Part 5 - Photoshop Techniques

I have a few questions about Adobe Camera RAW (ACR) conversion. Exposure, Recovery, Fill, Blacks, Clarity, Vibrance, Curves; do you have a set a preference for these settings?

OspreyAlright here we go...

Exposure - You use this slider to set the correct exposure. For many images you can set this by holding down the ALT key and dragging the sliders left and right until you have no over exposed areas of the image (i.e. the "exposing to the right side of the histogram" method). So if you had overexposed areas you would drag the slider to the left while holding down the ALT key until you had no overexposed areas. If you had no overexposed areas to begin with, you would drag the slider to the right while holding down the ALT key until you had some overexposed areas. Then you would ease it back to the left just a little until you had no overexposed areas.

With that said, exposure like many settings is what you decide it to be. Some images look better overexposed, and some look better underexposed, so the method above may not work for every image. You can always just drag the exposure slider around until you see what you like. I find this second method especially useful when the images were taken on an overcast day, indoors, or under a lot of shade. In this case you don't worry about overexposed areas because that's what we're going to use the recovery slider for.

Recovery - Once you've set your exposure, you can use the recovery slider to recover the portions of the image that are still over exposed. You can also use the ALT key with this slider to see which parts of the image were recoverable, and which part of the image will remain overexposed. One thing about the recovery slider is that if you drag it too far to the right on some images the whites will turn a little bit gray or yellow. Sometimes it fits the image just fine, sometimes you have to back off on the recovery slider to keep them white. Use the recovery slider in conjunction with the Exposure slider to get the overall exposure that you want. Of course it’s best to get it right in camera, but if we can't always wait for perfect light or to have exposed an image correctly the first time.

On a technical note recovery uses similar techniques to creating a linear and normal conversion of the raw image and then combining them. It's just that now you can do it with one slider. I tend to treat recovery like the highlight slider in the highlights/shadows dialog in Photoshop.

Fill - Fill is like the shadows slider in the highlight/shadows dialog in Photoshop. Just like the shadows slider if you drag it to the right too much you will reveal the noise in the underexposed part of the image. One thing to remember is that fill or the shadows slider does not add noise; it only helps reveal the noise that was already there. Ok, how much. It's again subjective to your liking. It's really there to substitute as a fill flash. I find that most of the time I do not use the fill slider and still prefer to use the shadows slider in the highlight/shadows dialog, because I tend to want to make color corrections first before setting how much fill I want. When I do use fill, I use it sparingly from +20 on an ISO 100 image to as little as +3 on an ISO 400 image. I hate noise so I try to avoid revealing it if possible.

Blacks - is pretty much the same as the black slider in the levels dialog. Used with the ALT key, you can see which areas are going to become underexposed. Personally I leave blacks at zero most of the time and just use the levels dialog to set the black point after I've done any cropping, because I want to see the final cropped image first before setting the black point. When I do set the black point I'm pretty liberal. If its part of the background and it's supposed to be black, I'll keep dragging that slider to the right until it’s completely black. Setting your black point adds the most contrast to the image, and I like lots of contrast for daylight images.

Clarity - I use this slider to see if I can add enough contrast back to the image to save a soft image. I know many of you will open an image zoom to 100% and then use sharpening to see if a soft image is worth editing. Well, I do the same thing, except I use the clarity slider. It adds contrast to an image without actually performing sharpening, so that when you do apply sharpening there is a reduced chance that you will get a halo. Most of the time I leave this slider alone, unless the image is soft, then I'll play with it to see if I can make a soft image better. You can play with this slider along with the sharpening slider in the sharpening tab to see if your soft image is worth editing.

Vibrance - The most I've added is +20 I think. I use this instead to Saturation as I tend to prefer the results vibrance gives over normal saturation. Again use is subjective and depends on the image.

Curves - I leave curves alone and set it in Photoshop if I have to.
Sharpening - I also leave this at 0. I don't want to sharpen an image until I have cropped, cloned, and color corrected. I use Smart Sharpen at 50% with a radius of .8 for web, and somewhere between 1.2 and 1.8 for printing. I save the PSD file unsharpened and always resize first and then resharpen for whatever I want to do. This keeps it flexible because what works for one printer does not work for another. I have to do less sharpening for the Epson 2200 than the laser printers at work. If there is a woman in the photograph always cut your sharpening in half. They'll greatly appreciate it.

Noise Luminosity - I leave this alone and use the noise reduction filter in Photoshop. Again I prefer to remove this noise after I've done cropping and color correction. I find Luminosity noise to be less objectionable and even film like in some respects.

Noise Color - I hate color noise. This is the noise you get from underexposing and image. I try to get rid of it whenever possible. So I set this slider to 50% as that gives me results similar to what BreezeBrowser produces. The one thing I really like about BreezeBrowser is how good it was at reducing color noise. I'll sometimes run the noise reduction filter in CS3 in addition to help get rid of color noise. If I can’t get rid of enough color noise, I throw out the image.

One thing about all of these new sliders is that you don't have to use them if you don't want to. You can get similar results by using the old dialogs in Photoshop. Of all the new sliders, Recovery is the one I use the most because I can now set exposure independently from recovering the highlights. The reason all of these new sliders are in Camera RAW is because they are required for Adobe Lightroom. Since Lightroom and CS3 now share the same RAW converter, CS3 users benefit from the new sliders. I have Lightroom, but I still use CS3 and Bridge 99% of the time. Lightroom is great if I want to take a picture now and print it immediately or "in about an hour". However if you're not under those time constraints CS3 is so much better.