Wednesday, 22 December 2010

Exercise 19: Correction

All images be they digital or film need to progress from capture to display. The techniques employed in between IE the processing, is when intervention can move from insignificant to significant. The basic image qualities are

  • Overall brightness
  • Overall Contrast
  • Density or blackness of the darkest tone
  • Density or whiteness of the lightest tone
  • Overall colour cast - white balance
The raw file is often compared to that of a film negative, both being the intermediate stage between capture and display. Correcting any of the fundamental image qualities is accepted as the norm or the standard and no-one argues against optimising any of these qualities. However when does correction begin to move from basic correction through to interpretation and creating an image far removed from the initial scene capture and depart from the "standard"?

For task 19 I need to investigate two widely accepted reasons for correction; dust spots and lens flare. There are several images taken recently that have blemishes; I change my lenses quite frequently and recently discovered that at smaller apertures I obtain more noticeable dust spots in areas that lack detail such as plain backgrounds and clear skies. I feel a trip to the camera shop for a spring clean!

Dust Removal

This image of a boat in a frozen lake has a few dust spots visible in the sky and on the ice. There are several tools in photoshop which you can use to remove dust spots but the ones I favour are the healing brush and the clone stamp tool.

In this instance I used the healing brush to remove the dust spots in the sky and a mixture of the healing brush and clone stamp tool for the dust spot on the ice.

When making these minor adjustments I still like to keep the 'innocence' of removing dust and retain as much of the detail from the original shot as possible. Dust on the sensor is not part of the scene and is down to equipment 'failure' and I see no problem with removing dust spots.

As you can see from zooming in at 100% on the before and after images removing the large blemish from the ice has not altered the scene at all.

Lens Flare

Lens flare is not always a mistake on the part of the photographer, occasionally it can be used to create an atmosphere or for artistic reasons. In my photography I have a mixture of both, sometimes the mistakes add to the image and sometimes the deliberate inclusion does not always have the desired affect! Removing lens flare can be tricky. Depending on where the lens flare falls depends on the tools you can use to try and remove it. Sometimes the clone stamp is the best option and on occasion I have used marquee tools for precise selection either to adjust the selection or duplicate an adjacent area to 'cover' the flare.

This woodland scene was shot early in the morning as the sun was rising. The intention was to catch the suns rays in a starburst effect from behind the trees. Not using a lens hood I had expected to get lens flare and I was interested to see what the actual effect would be. I had not anticipated the large white glare at the bottom, which at the time I felt detracted from the overall image.

For my own satisfaction I faded the white flare so it blended in and was not as obvious but felt the lens flare did not spoil the final image and let it remain. Shooting at this angle into the sun you would expect lens flare to occur and naturally be part of the scene.
I felt this would be an ideal image to use for this part of the exercise. I have never used the clone stamp tool with different modes before so I was interested to see how it coped in this situation. Experimenting with both Lighten and Darken I found it not very successful, due to the intricacies of the light and shadows of this scene. I therefore reverted back to straightforward cloning in 'Normal' mode. This was also a very fiddly job but I was more satisfied with the results. This maybe because this image lent itself more to Normal mode or because I need more practise with other modes.

So the question to be answered is "should lens flare remain?" In the case of the above image the intention was for it to be there, has the image lost anything from it being removed? I personally prefer it with but can see the merits of its removal. Do I think the image is now not as honest? In reality nothing has physically been removed from the scene, a few blades of grass or leaves may not be in exactly the same place but no trees or fence posts have been removed, in essence the scene is the same as it would have been had I slightly altered the camera angle therefore ethically, in my opinion, I don't this there is anything wrong with removing lens flare. Is it necessary to remove lens flare if it is a mistake? I don't always think it is, but if distracting from the main subject then I can see why in some cases it would be better to be removed.

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