8.30.2008

Photoshop Tips&Tricks: Focus/Shake Recovery

Some images may be recovered or made better from camera shake or bad focus by a simple Photoshop sharpening technique. The results really depend on how badly the image is affected.

1. Open image and duplicate layer (Layers -> Duplicate Layer. Name your layer "Sharpening Mask")
2. Change blending mode of the "Sharpening Mask" to Luminosity (Layer -> Layer Style -> Blending Options. Select Blending Mode to Luminosity)
3. Unsharp image (Filter -> Sharpen -> Unsharp Mask. Select appropriate settings to taste. If image quality is severely degraded, amount is usually kept to higher numbers. Radius and Threshold values are usually kept very low (e.g. 1).
4. Duplicate "Sharpening Mask" layer, and apply Gaussian Blur filter to recover image quality.
5. Modify layer's opacity to your taste and apply Color blending mode to the layer (Layer -> Layer Style -> Blending Options. Select Blending Mode to Color).
6. Modify Curves/Levels adjustment to help bring out the detail.
7. Flatten layers to finalize image processing.

This image is very blurry due to the camera shake during the exposure. While letters offer some readability, architectural and stain glass detail is severely brulled out.

After applying sharpening mask technique on the image, smaller letters are more readable, and detail is recovered in the architectural detail and stained glass. This solution is not perfect for severely blurred images, but work really well in less extreme cases of camera shake and soft focus.

Photoshop Tips&Tricks: Contrast Mask

Very often times composition will create light/exposure challenges. For example, very bright sky and dark ground. Another common occurrence is intentionally under- or over-exposing the image in order to capture important detail. This is common when trying to retain bright colors and highlights of the sunset or details in dark object(s) near a strong light source.

As a result of scewed exposure, portion of the photograph unavoidably contain too much dark or light areas. One of the ways of compensate for this drawback is to use HDR technique (covered in previous post). However, that may not always be possible. Further, HDR introduces "surrealistic" feel to the image, and this may not always be artistic intent. The simpler approach is to use Contrast Mask easily rendered in Photoshop (although this technique does have roots in film photography dating to nearly 100 years ago). It is best that contrast mask is applied to images in RAW format, but works just as well with JPEGs. Here's how:

  1. Open the image and create duplicate layer of the background (Layer -> Duplicate Layer). Name your layer "Contrast Mask"
  2. Convert "Contrast Mask" to monochrome image (Image -> Adjust -> Desaturate)
  3. Covert "Contrast Mask" to negative (Image -> Adjust -> Invert)
  4. Apply overlay blend to the "Contrast Mask" (Layer -> Layer Style -> Blending Options. Select Blending Mode to Overlay).
  5. Reduce image degradation by blurring (Filter -> Blur -> Gaussian Blur. Select desired pixel radius value. Larger values tend to introduce halos on sharp contrast areas, while low amounts minigate the effect.
  6. Adjust opasity of "Contrast Mask" to the desired level (usually anywhere from 50-80%)
  7. Fine-tune the image by adjusting levels and curves to your taste (Layer -> New Adjustment Layer -> Levels/Curves. Check the box "Use Previous Layer to Create Clipping Mask" to apply changes to the "Contrast Mask").
  8. Flatten layers to finalize image processing.

This image was intentionally underexposed in order to capture sun beam highlights in the sky. As a result bottom portion of the photograph is too dark. Adjusting curves or contrast of the image will sacrifice the dramatic sun beams of the sky rendering them hardly visible.


After applying contrast mask, the colors and highlight of the sky were retained, and initially very dark areas were brightened to reveal all the detail and color.

8.19.2008

David Griffin on Photography

Ted Talks had released a video today (originally filmed in February 2008) of David Griffin's overview of world photography. Griffin's work is known world wide and earned him much recognition and awards. He is currently a photography director of National Geographic magazine.

In this talk, his insights are thought provoking as he overviews world and personal perceptions captured and reflected through film. Most importantly, he conveys that little something something that allows to grasp what separates armature photographer from a photojournalist. (I gap that I myself am hopeful to mitigate.)