Digital Photography/Post Processing

{This module needs expanding}

Post processing is the process of editing the data captured by a camera while taking the photo taken to enhance the image. The better the data captured from a camera to create the photo the better the enhancement possibility is. There are more and more cameras which have come into market which can capture RAW files. Raw files have much more data at a pixel level which help in post processing and enhancing the image.

Post processing can help in enhancing the image but might not be able to convert really bad exposure to excellent exposure. There are various stages of post processing based on what the final result that one wants to achieve.

1. Fine tuning a RAW file.
2. Converting a RAW file to easily readable formats like jpg/png/tiff.
3. Editing of jpg to remove unwanted features.
4. Mixing of various files to achieve a creative result.

Software

There are basically two things that are done in post processing :

1. An algorithm is run on all existing pixel data and minor changes are applied to the pixel data.
2. Manually selecting and Replacing the pixel data with new data.

There are software's by camera manufacturers, specialist software vendors and free software available for taking care of post processing.

RAW file handling and conversion is possible in RawTherapee, UFRAW, darktable, Adobe Lightroom, Adobe camera RAW, FSViewer and many more.

Jpg file editing is generally done in image editors that have various features such as grain and red-eye removal, for example, Gimp (free), Adobe Photoshop (paid), or Photoshop Elements (paid).

Work flow of post processing

There are lot of changes possible during post processing. Sequence of these changes is important as change made at one stage can affect the effectiveness of next stage. Most of the software are also organized in a fashion to guide the users through a smooth work flow.

Few actions can achieve great results when applied in RAW file. These can also yield result in jpg files in case you do not have RAW file.

Some of actions that may be preferred while editing RAW file are

1. Exposure Value adjustment
2. White balance adjustment
3. Hue and tone adjustment
4. Highlight and shadow recovery
5. Vibrance and saturation adjustment
6. Cropping & Rotation

Some of the actions that can be done at RAW or jpg stage are

1. Noise reduction
2. Sharpening

Some of the actions that are preferred after conversion to jpg files are

1. Red-eye removal
2. Local touch up of cloning to erase unwanted object in frame
3. Adding of frame
4. Mixing with other jpg files like changing the background.

Removing red-eye

Example of red-eye.

It's much better to avoid red-eye than to try and remove it in post-processing, as red-eye means you lose the color details of your subjects eyes and can't recover it.

Basically it is done by replacing the red flare with black and adding a white high light to the black dot.

Some Photo-Editing programs provide "Red-eye" removal effects.

Adjusting Colour balance

When photos are taken, some colours often do not appear real. This can be adjusted using the software above. Microsoft Photo Editor, for instance, allows you to balance individual colours and preview them before okaying them.

Converting to black and white

Many times one can emphasize certain picture by converting it to gray-scale. There are various ways of doing so depending on software being used.

• Converting layer from RGB to Gray-scale
• De-saturating
• Decomposing to HSV or RGB and using one or more layers to compose the image