Digital Hints & Tips - Retouching

• Conversion of Colour Image to Monochrome - Tony Godwin
  1. Select – IMAGE-ADJUSTMENTS-CHANNEL MIXER
  2. Tick the MONOCHROME box at bottom right hand corner
  3. Adjust the numbers at the right hand side of the colours. These must add up in total to 100 (you can use negative and positive values as long as the sum comes to 100 i.e. 65, 40, -5)
  4. A suggested starting point is Red 43, Green 33, and blue 24. This represents a black and white film using no filter.
  5. Click PREVIEW on and off in Channel Mixer to see the effect.

  Should you wish to simulate the use of a filter the following figures will do just that.

  Filter colour you wish to simulate	Red	Green	Blue
  Red	75	25	0
  Yellow	58	20	22
  Orange	65	20	15

  NOTE: Do not use IMAGE-ADJUSTMENTS-DESATURATE to produce monochrome images as it is much inferior to the above system. (If you do not believe me just try it out).

• Dealing with Red Eye - Tony Godwin
  1. Select the Layers Pallet in WINDOW at the top of the screen. Then drag the blue area of the Background Image in the Layer Pallet down to the second icon from the right. (This looks like a piece of paper with the corner folded over).This will produce a Background Copy to work on
  2. Enlarge the image of eye by selecting Magnifying glass in the tool options bar (This can be done by pressing Z key).
  3. Click on eye several times until it becomes of reasonable size to work on, around 1 inch in diameter.
  4. Select Lasso tool and set FEATHER at the top of the screen to 1 pixel. Draw a approximate circle around the red portion (Include all red area)
  5. Hold down space bar and drag the image across the screen until the other eye is in a convenient position to work on. (Holding down the space bar lets you move the image about the screen at any time.)
  6. The Lasso tool should still be selected so hold down the Shift Key and draw a selection around the second eye as you did with the first. (Holding down the Shift Key enables you to draw further selections without losing the earlier drawn ones)
  7. Select Channels in WINDOWS and then click on the green channel in the Channel Pallet. Select EDIT at the top left of the screen, then click on copy while in EDIT.
  8. Click on red channel in Channel Pallet and once more click on EDIT at top left of screen and this time select paste. (This pastes the green channel into the red one).
  9. Click on to RGB at the top of the Channel Pallet.
  10. Press Control key+D to de-select the selection from both eyes.
  11. Press Control key+O, or double click on the Hand (Move Tool) in the Tool Bar to shrink the image to fit the screen.

  There you have it. This is the best of many ways to remove red eye

• An unusual use of USM - Laurie Wilson
  Here's a counter-intuitive Photoshop trick that can make a huge difference in some images, in terms of removing that haze and adding a sense of dimensionality:
  1. Do an Unsharp Mask operation with the following settings: Amount: 10% to 20%, Radius: 30 to 60, Threshold: 0 or 1. I usually use 15%, 45, 0.
  2. This operation doesn't sharpen the image in the way we normally see using a large amount and a very small radius. Instead it boosts local contrast within the image.
  3. Global contrast is not affected. A large area is not changed, only areas near higher-contrast borders. Small detail is enhanced, since its difference with the average luminosity of a small area surrounding it is enhanced. Sort of like raising the MTF of your lens for the higher frequencies.

  I guarantee you'll like the effect.