"Out, damn'd spot!" Dust and Scratch Removal

While the words of Lady Macbeth might be taken somewhat out of context, finding out that treasured photographs (slides or film) have been damaged by age, weather and accidents can be pretty infuriating.

Fortunately though, we live in a time where technology can come to the rescue, sortof. Infrared Scanning can remove dust and scratches automatically though only from semi-transparent original media and it's only a feature on rather expensive scanners. Photo Editing programs usually have a 'Dust and Scratch Removal' filter - but often that ends up as too strong, or not strong enough.

That leaves hours and hours of painstaking manual correction -- or does it?

More recent releases of Photoshop have 'Content Aware' repairing, which does a fairly good job of doing, well, exactly what the name implies. Depending on the exact type and extent of the offending marks, this might be simultaneously overkill (the individual damage points aren't very large) and inadequate (the damage is spread out over the entire photo).

Lots of dust, hair and scratches - everywhere.

As is often the case, there is no *single* solution. Nor is something entirely automated the best way to go. At the same time, unless you only have a handful of photos (and really, how often is that?) you want something that doesn't take too long for each image.

After a *lot* of practice I found a method which strikes a rather comfortable and acceptable balance between time/tediousness and final quality.

It assumes a basic knowledge (and quality) of Photo Editing programs - duplicating layers and creating/using masks - as well as being able to adjust filter settings to produce a desired result. If you are confused over any specific step, please leave a comment, or do a Google Brand Search™ for a more detailed explanation. I'm avoiding specifics here because the exact menus and settings vary a lot from program to program.

1) Start by doing a 'Dust/Scratch Removal' at settings that improve the image somewhat but do not affect the image in undamaged areas.

Scratch Removal on lighter settings removes much of the small stuff, but doesn't touch the bigger damage.

2) Duplicate the lightly repaired layer and do 'Dust/Scratch Removal' again, this time with the goal of removing all the imperfections.

Using the more aggressive settings for dust/scratch removal repairs the picture, but also removes a lot of the detail - even in undamaged locations.

3) Mask the 'over-repaired' layer (Hide all) and selectively reveal it in areas where the spots and scratches are visible. Note the white dots in the mask (far right) in the image below.

Best of both worlds.

Composition - A more interesting photograph

It doesn't take much to pick up a camera, point it at something, and push the shutter button. However, if that's all you're doing, it's usually pretty obvious.

Which isn't to say it's an unforgivable thing. Some subjects are outstanding enough on their own that it's difficult to take a dull picture of them. Or it could be more about capturing the moment than making a work of art. Other times, it's more important *who* is in the picture rather than how (subjectively speaking) 'good' it is.

This usually relegates photography almost exclusively to vacations, specific events and pictures of friends and relatives.

That said, even if that's all you want to do, why not make it a bit more than a simple snapshot?*

*Disclaimer: The opinions expressed are mine, and are only that. If you don't like constructive criticism, you might want to stop reading now. Also, the pictures are also mine, so I'm not tearing down anyone else's work (except by implication).


Rules of Thirds - Simplified

If you take a (potential) picture and divide it into thirds horizontally and vertically, the lines segment the picture into nine pieces. The corners of the centre segment, as well as the 4 dividing lines should be where 'points of interest' are in your photograph.

Or, more succinctly - don't centre stuff.

A rather common 'mistake' in most snapshots is to put the subject as the absolute middle of the picture. While it's a rather good way to make sure said focus is in focus, it's the photographic equivalent of clubbing people over the head saying 'This is what you should be looking at'.

Look at me! I'm in the middle! Look at meeeeeeeeeeee!

The solution is rather simple, as most cameras focus when pressing the shutter down half way. Once focused, continue holding the button down (partially!) and change the direction the camera is pointing - even slightly.

A bit further off centre and the image is less harsh.

Room to Breathe

Another slightly grating habit is to have the subject of the photo take up most of the photo. While this may seem a desirable outcome, there's a few reasons why it isn't:

It's a picture of a flower - and not much else.

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First - from a practical standpoint - it makes it terribly difficult to recompose the picture later when cropping. Facebook profile pictures are square, 4x6 prints are 2:3 (clearly rectangle), and 8x10 photos are 4:5 (wide squarish :p). 'Fill' any of these and you'll likely have problems. As I've mentioned before.
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Secondly - from an artistic point of view - a picture that's 75% subject tends to be more than a little busy. Negative space is almost as important to a picture as the actual subject - don't skimp. It's also likely violating the 'rule' above and being entirely centred. Last, but certainly not least, it's missing context - where is this in relation to everything else?
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Thirdly - from a technical perspective - it really isn't necessary. Cameras take in a *lot* of information. If you're interesting in minuscule detail, like individual eyelashes or the exact weave of clothing, then you might want to fill the frame with your subject - macro photography comes to mind. But otherwise don't be afraid to cram a few more things in.

Under relatively ideal conditions a 12MP (DSLR) camera can take a picture of 50 people at once, leave enough room to show what room they're in, put their names at the bottom AND have enough individual detail to make a passable Facebook portrait for each person in the shot.

Unless you're cropping out a lot of your picture later, or printing at 13x19, you'll lose most of that detail anyway.
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A little context for the image helps it out a lot.

My personal 'rule' is no more than 1/3 of the picture as the main subject. There's exceptions to that, but that's another post....

Quick Tips

In the interest of having a 'bite-sized' post and a bit of a review/re-link to my earlier posts - here's a bare bones list of tips for Photography and Photoshop. I'll try and list them from simplest to more advanced.

Photography

1. Shoot pictures in bright light. The more light the better, diffused light if possibly (less harsh shadows)
2. Learn the different shooting modes. With the exception of the very inexpensive Point and Shoot cameras, there are ways and reasons to control some things directly
3. Adjust the exposure compensation If you can't shoot in bright light, this does help
   
4. Set the White Balance. Or at least know what else you can do about tinted pictures

Photoshop

1. Sometimes the best fixes are quick Autocorrect is your friend (most of the time)
2. The next best things are automated You just have to know where to find them
   
3. Know what the program can do Part 1 Part 2 With enough time, source pictures and expertise, just about anything is possible
4. Blending options are a quick way to add some pizzazz

Automatic Image Correction - Do you feel lucky?

Well, do ya, punk?

Auto image correction, whether in Picasa (source of the question) or in Photoshop is a quick way to (sometimes) improve your image. Luck doesn't really come into the picture though, as the Undo button can always fix this one-step action.

Fortunately though, it usually does benefit your image, or at the very least, does nothing all that noticeable.

Most of the time it seems to focus on the contrast of the image.

As you can see, the difference between Picasa and Photoshop is minimal. However, the advantage with Photoshop is that you can Fade the result in the case it seems too extreme.

Quite often though, it also tries to remove a colour cast from the photo as well. Often (in my pictures at least) this tend to add quite a lot of blue to the image - often where it really doesn't belong.

In a few cases, typically those shots with a small number of colours, it goes in a very bizarre direction.

UNDO!

Rule of -2/3rds

It's possible you've heard of the Rule of Thirds. It's a guideline for composing photographs so that your focus *isn't* the dead center of the picture. This, however, is not what this post is about.

Instead it's a personal rule of mine to override the camera's Exposure Compensation.

Now when you take a picture the camera decides, based on some other settings I won't go into yet, how bright to make the picture. It adjusts (depending on what mode you're in) the ISO (sensitivity to light) and/or shutter speed and/or amount in focus.

More often than not, I find it's a bit brighter than I'd like. Colours are often washed out, and natural things don't look that real.


Normal Exposure

- 2/3rds Exposure

Now it's a little difficult to tell after the fact what the exposure compensation is, since it doesn't show up in most programs - even the ones that normally show the ISO, shutter speed and all that other fun stuff. It is recorded as 'Exposure Bias' in the EXIF information - check the >Properties of the picture in question (Details tab if you have to click farther).



Normal Exposure

- 1/3rd Exposure

- 2/3rds Exposure (/w Auto Contrast in Picasa)

-1 Exposure (/w Auto Contrast in Picasa)

While this is a personal preference, there is a technical benefit as well. When dealing with digital cameras, it's better to err on the side of too dark. Shorter exposure time means less chance for a blurring. If you're happy with the shutter speed, a negative exposure compensation will allow more of your picture to be in focus. When both of those are fine, it will allow for a lower ISO setting, which means less rainbow speckles in the picture and richer colours overall.

Often if something is dark and you'd like it to remain that way in the picture a lot of negative Exposure Compensation is needed.


-5/3 Exposure

Another benefit is making details of white things visible - and not clipped out beyond the upper range of the camera.

 

Normal Exposure (above) - 4/3rds Exposure (below)

 As with most camera rules, there's times when they should be broken. If you're outside on a bright day, but your subject is under some small shadow it would be worth going to positive exposure compensation. Similarly if your subject is backlit and not showing up properly, this is a quick fix.

Most cameras do have Exposure Compensation. However, you will have to go into the letter modes of the settings (previously linked). Some cameras will show it as a fraction, in steps of 1/3 or 1/2 while others will show a decimal value. Check your manual.

Macro Photography

Definition

Now, technically, macro photography only applies to situations where the subject of the photo is the same size as the image sensor (35mm or smaller) - and takes up the whole frame. This is known as 1:1 magnification.

For the purpose of this article, however, I'll simplify to things the size of a quarter or smaller being the main subject.

Method

Generally speaking, there's two ways to go about taking a macro-type shot.

The first is the more obvious. Get as close as possible and take the shot. Many Point and Shoot cameras have a Macro mode - usually indicated by a 'flower' icon. This tells the camera to focus on things that are closer to the camera, rather than things that are farther away (like mountains - the complimentary symbol).

While this method can produces the largest and sharpest pictures of the subject, there's a few drawbacks. One is that you're likely to create shadow, and that hampers the camera focusing, or at the very least, reduces your depth of field (amount of things in focus).

Normally this wouldn't be a problem, but the DOF is very small at close distances already. Not an issue when things are flat and perpendicular to the camera, but that doesn't always happen. Even things as small as bees and flies might not be in focus from front to back or edge to edge (depending on your angle and if you can get them to cooperate).

Which leads to the other problem - most living things (that you'd be taking macro shots of) don't like people in their space. Even if they aren't bothered, trying to get to as close as you can and still being able to see the screen/subject might be difficult.

Bright lighting will help the first problem - but if you're using a flash, it can be overkill. Bright, noisy lights don't help with the second issue either.


So what's the other option? I'm glad you asked (even if you didn't, you're still reading).

It might seem counter intuitive, but put the zoom to as high as it will go and be prepared to stand back. Your minimum focus distance will be quite large - at 10x zoom about 1m/3 feet. The larger your zoom, the more unlike the first method it will be and the farther you'll have to be from your subject. Which is, given the problems listed above, not always a bad thing.

The drawbacks to this method include a lower image quality overall - but better than you might think, especially in bright sunlight. At higher zoom, depending on camera/lighting, camera shake might be a problem. Your angles are also somewhat limited - it's hard to get directly under something that's closer to the ground than your minimum focus distance.


Equipment
As much as I've love to recommend a DSLR camera with dedicated macro lenses to everyone, it's probably not going to happen. While the price of the camera body is coming down a 50mm macro lens is only barely under $400. Still inexpensive for a lens (comparatively), but it's a one-trick-pony. While you *can* take pictures of larger things, a 50mm prime lens will take in quite a bit more light, be a lot cheaper, lighter and quieter. The 100mm and larger macro lenses give a larger working distance and increase magnification as well, but expect the price to double or quadruple (!). Almost as effective is a 250/300mm zoom at the minimum focus distance as seen below - click for full size.

Above: 250mm lens 1.1m/3.6 feet away
Below: 50mm macro lens ~23cm/0.75 feet away

That said, with the sheer amount of information that any camera today takes in, with time, patience and being in the right place at the right time, you can get a excellent shot with just about any camera.

Those Crazy Letters

Most cameras will let you pick them up and start shooting right away. Set the camera to Auto, indicated by a Square, the word 'Auto' or some other picture (all dependant on camera type, but almost always green) and it will adjust the settings for you. A lot of the time 'right' as well. Which is to say they generally get the shadows dark, but not pitch black, and the whites bright, but not blown out entirely. A good number of things are in focus, and - if it's light enough where you are - not blurry.

Certain times you're in a specific situation. Night Portrait, (Day) Portrait, Beach, Snow, Sports/Action, Landscape... and your camera probably has a settings for that too. Indicated by a semi-descriptive picture and the words on the screen when you go through them. Some really go all out and have a rather lengthy list of custom scenarios. (On a beach, at night, while it's snowing and you're lit by candles being slightly too specific, but they're getting close)

But enough about those. They don't really need an article. P Tv Av M. Or possibly M A S P do.

Picture via Flickr - You'll notice I leave out A-DEP, but so do a lot of cameras

Let's go through them from 'easiest' to 'hardest'.

P - Program
When you'd like a little more control over your camera than is possible with the auto function, start here. It unlocks a lot of things like ISO (sensitivity to light, just like film, higher is more), over- or under- exposing the shot, different file options to save (RAW, if the camera has that feature) and so on. Unless you change anything, however, it does tend to act like Auto - in that it does do a lot of the calculations for you. The difference being, you now have the room to nudge them in a certain direction.

Tv or S - Time Value or Shutter Priority
Next on the list, as it does what it sounds like. This is handy for action shots, or wildlife (children included ;) ) that won't stay still. Set the value to 1/200 second (or more) and you can freeze a lot of things that would otherwise look like a blur. The camera still has the room to adjust the aperture - or how much light comes into the camera. The tradeoff being that the faster you set the camera the less number (or more accurately, less depth) of things end up being in focus. Force it to go extremely fast and you'll notice a very dark picture. Ooops. Learning from mistakes is just as valuable as learning from success.

Av or A - Aperture Value
This is where things get a little odd. All you really need to remember is that the smaller this number is, the less of your image will be in focus. Conversely, setting this number higher will result in a lot more things (or specifically depth) being sharp. As always there's a downside to pushing the extremes. The higher you set this value, the longer the shutter has to stay open. Which can lead to movement blurring or past a certain threshold, less sharpness overall. It is, however, quite handy for extremely closeup shots - as the closer something is to the camera the less 'depth' is actually in focus. More on that in an upcoming article.

M - Manual
While the previous two modes had the camera adjust for the 'missing' value, here everything is up to you. You'll notice that if your camera has an option for over- or under- exposing the shot, it, almost paradoxically, vanishes. This is because everything is under your control - so it will be bright, dark or just right based on your settings -- with no help from the camera. As you might guess, this does make things a little tricky. I would very strongly recommend a few test shots in the other modes first so you'll at least have a starting point. This mode is most often used (at least by myself) when the other two modes overcompensate, or vary the 'missing' value and I want to override that.

Example #1: Taking the first shot in some other mode and forcing the same settings for the following shots - with the intent to stitch them together afterwards. Otherwise you could find a wide variance in exposure or amount of the image that is in focus from image to image.

Example #2: 'Forcing' a larger region of focus AND having a short shutter time - at the expense of image brightness - often used when something is both close to you and moving. This is when you can find the other modes are falling short. If the speed is fast then not enough is in focus OR it leaves the shutter open too long (and a blurry image) when adjusting for the focus alone. While I could also go into Tv/Av and say I want an underexposed image, I wouldn't know by how much. It would be easier to set both the Av to what I want (say 5) and the shutter speed to something useful (1/200s).



Apart from spinning the dial, it does vary quite a bit from camera to camera what buttons change the values in question. Do check your manual. If you've lost it, most camera manufacturers also make a copy available online.