Post-processing: Tips and Tricks for Working with Your Pix

[motowriter]

Ralph/zrx1200 from Ontario posted a thread in which he posed some questions about post-processing digital photos. Specifically, what kind of post-processing is typical? And how about shooting in RAW mode with a digital SLR? So here are some thoughts on post-processing and a peek into my bag of tricks, one or more of which I tend to use on three-quarters of the images I post here.

RAW/JPG: I shoot only in JPG. While post-processing RAW offers some very neat tweaking to the original image (like going back in time and changing the camera settings you used, but after the fact), the RAW images would overwhelm my hard drive given the number of pix I take. RAW format results in much larger images. And you have to process ALL the images to get them into JPG, not just the ones that you may want to play with. I can come home with 200 pix from an afternoon ride. I just don't have the time to process so many photos.

I use a set of tools that I have come to rely on in Photoshop to deal with common outcomes from a photo shoot. I suspect I could overcome all the issus if I were better at setting the aperture and shutter speed on the fly. But I'm still learning, in that department, and just can't predict very well how to set the lens to match the available light and action.

I have a copy of Photoshop 7.0, but I don't use it. I bought a copy of Photoshop Elements (PSE) as it is easier to use and has all the tools I need to post-process JPGs. Here's my standard tool-kit:

Cropping: Sometimes you need to crop. Since composition does not require manipulating aperture and shutter speed (for the most part... composing with depth of field is another matter), this is the simplest thing to apply to an image. This is where an SLR that captures large images, in megapixels, can be a real advantage. I can zoom in quite a ways on the JPG image I end up with and isolate something cool that I didn't necessarily see at the time I shot the photo, or on something that I couldn’t zoom in on within the range of my lens. But, I've improved quite a bit in terms of composition and tend not to have to crop many images these days. Practice, practice…

Contrast/Brightness: I rarely adjust for brightness (there are better tools for that job, like Levels) but I treat maybe 50% of my outdoor shots with added contrast to overcome wash-out and haziness and to restore crispness and depth of color.

Levels: I use this as another way to correct contrast. Its graph display of light saturation (what Photoshop calls the “tonal range”) is very helpful in determining just how much to adjust in one direction or another. Very useful to either darken or lighten an image.

Curves: Another way of manipulating the tonal levels, this tool requires some practice and is one I tend to use only if Contrast and Levels are not working to effect my desired correction.

Shadows/Highlights: This is a bit of a cheater from PSE, but I use it frequently. I'm not sure what the equivalent tool is in other editors (gamma maybe?), but I believe this is available in CS2. On this one I generally only use the Shadows adjustment to lighten what’s obscured in a picture that’s under-exposed. It’s an excellent tool to bring out detail that you can’t see in the original image. While the default setting in PSE is to lighten shadows by 50%, I tend to think that makes the image look unnatural, so I take it easy on how much to apply.

Selection Tool: I will on occasion use the magnetic lasso tool to select part of an image that needs some help, where the rest of the image is fine. Once a section or object is selected you can use the group of tools above to correct what’s not right. I use this infrequently, and in most cases I use it to select a bike/rider in a shot and use Unsharp Mask to reduce the blur (caused by my failure to adequately set focus on an action shot).

Healing Brush / Cloning Brush: A biggie in the cheater category, and likely to produce a philosophical argument… I use this on occasion to remove objects from a photo where the object detracts from the overall image or pulls the viewer's attention away from the composition of the shot. I’ve removed road signs, the tall snow-height poles, electric wires, telephone poles, even a car now and then. Sometimes you just can’t get a shot without a major distraction in it. You get home and look at it and say “if only that thing weren’t there”… and then you click on your clone tool to make the distraction go away.

[motowriter]

K, so let’s see some examples of what I’m talking about. On a weekend ride in Phoenix in February I shot about 250 pix in 24 hours, from Friday evening to Saturday evening. The photo essay of 50 photos or so is posted here http://www.pashnit.com/forum/showthread.php?t=10351.

Cropping

Before cropping, the rider is simply in the middle of the photo. Not a good composition, but what I got from where I was positioned.



After cropping, the quality of the image is still very good since I cropped a 10mp image that was a 6mb JPG original. (Click here to see the original in full size). The composition is much improved and the zoom on the subject makes for a nice display of the rider in action.



Contrast/Levels/Curves

A good number of outdoor photos I take in bright light tend to be washed out. Manipulating the white balance setting on the camera can help compensate for this, but is not always effective. Nor do I always remember to change the WB depending on lighting conditions.

Before contrast applied, the photo is a bit murky.



After contrast (or levels), the colors are richer and you can see more detail in the ridges at the top of the mountain.



Shadows/Highlights

The brush in the foreground in this early evening shot lacks details, lost in the shadows. The colors and detail on the background are not obscured and won’t be affected by applying the tool.



Lighten the shadows and voila! Detail exposed.



Selection Tool (Unsharp Mask)

In this image I was panning the camera while centering focus on the rider. However, my shutter speed was set a little lower than needed so the subject I focused on was a bit blurry.



Rather than sharpen the whole image, I used the magnetic lasso to select bike and rider and apply unsharp mask to it. I want the background to be out of focus and only get the subject of the picture sharpened.



Clone Tool

And finally, the controversial clone tool. The healing tool can sometimes fix small blemishes in an image by copying the surrounding area and averaging out some replacement pixels. The cloning tool is more of a manual effort than the healing brush and requires selecting a replacement selection for something you don’t want in the picture. The image below is before cropping, and captures a number of buoys on the water that, to me, detract from the overall picture with its brooding tone and solid palette of contrasting colors.



After cloning nearby bits of water and replacing the white spots, the image is much improved.

[motowriter]

The key to using post-processing tools lies mostly in the photographer’s ability to compose and shoot a decent picture. For me, the bag of tricks I use simply helps make a good photo better. One can rely too much on these tools which is why I strongly urge those with an interest in photography to get out there and practice! At first you may only get 1 in 20 shots you like. Over time that number increases and the number of images you feel need tweaking will diminish. Personally, I’m pretty happy with a lot of the photos that come off of my camera, with no post-processing. But that wasn’t always the case. Practice practice practice!

I've only been using an SLR for a little over a year. I still have a lot to learn and I firmly believe I will some day build up the skills to overcome the things that I address in post-processing. For point-n-shoot photographers, you may have no control over the elements that make a "great" photo come out only "good" as a JPG image. The post-processing tips here ought to help restore some of the original brilliance that your eye saw but your camera didn't capture.

As a post-script, and in the interests of humility, I do take my fair share of stinkers every time I go out to take pix.

Whether I didn't deal with the lighting adequately...



Or didn't manage to focus (at all!)...



Or simply settled on a mediocre (and boring) composition...

[Bandit66]

I would like to mention that all this and more is available for free with GIMP, the GNU Image Manipulation Program. That link sends you to the Windows executable, but it is also available for Mac OS X and of course all sorts of Unixes.

I agree with Gary that these are not miracle tools. Crappy pics, above all if only jpg is stored, will stay crappy despite what sometimes takes a lot of time. But when you shot a scoop and no one else did, it is worth a little work.

Gary, red eye removal is also quite useful for us without sophisticated flash systems. As for the other tools, it seems to work better if you select the red part before.

Red eyes:


Blue eyes:


=oS`o
Eric

[Bandit66]

Originally Posted by Gary

Or didn't manage to focus (at all!)...

[img]IMG_1223.jpg[/img]

Thanks. Just found a new desktop background ;-)

[motowriter]

Good tip on the red-eye, Eric. I seldom photograph people, so I tend not to use it too often. I'll have to check out the freeware photo editor. Gotta love GNU! And that blurry madness is an Aprilia Futura, the photo taken immediately after my cropping example, when I didn't have the burst-mode turned on and was frantically trying to get another shot of the rider on the same curve!

[zrx1200]

Hey Gary,

Thanks for the chat about your photo tools.

On the side of taking photos its going to be a new challenge for not only to use the new SLR to its potential but to slow myself down and take the pixs. This year will less miles I think and more stopping. Will see......

[half_a_tiger]

Some words of warning, though, when editting graphics in JPEG format, considered a "lossy" format... Image quality deteriorates on every correction and "save" process. Graphics with Levels/brightness/contrast/color correction can be done up to a certain limit and may look good on screen; but may produce unexpected (a.k.a weird) results when producing an actual printed hard copy.

This is mainly the reason why certain people would rather work with RAW images, a "lossless" format where changes can be effected without causing deterioration to the original image.

[nodaclu]

Thanks a million for the tutorial Gary!

I learned about about PSE - a program I've had for 2+ years but barely know how to use properly.

I'll keep this around and see what I can learn from it.

~Mike

[Bandit66]

Originally Posted by half_a_tiger

Some words of warning, though, when editting graphics in JPEG format, considered a "lossy" format... Image quality deteriorates on every correction and "save" process.

True. The GIMP allows you to save intermediate stages in a lossless format while you work, then convert your final image to jpg. The quality and compression levels can also be adjusted.

Originally Posted by half_a_tiger

Graphics with Levels/brightness/contrast/color correction can be done up to a certain limit and may look good on screen; but may produce unexpected (a.k.a weird) results when producing an actual printed hard copy. This is mainly the reason why certain people would rather work with RAW images, a "lossless" format where changes can be effected without causing deterioration to the original image.

True also. I recently tried to correct a grossly over-exposed background, but the jpg compression had lost all information and replaced everything in pure white. The raw image would have probably been correctable, but the jpg was irremediably lost. As Gary said, the main problems with this format are storage space and processing time.
--
Eric