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Carl
Volk's
Photoshop Tip of the Month
Combating Flash Fall-OffWhen a photographer is limited to the flash on the camera for his/her main light source the brightest areas of the photo are closest to the camera and the intensity of the light decreases quickly creating over-attention to the foreground and too much contrast throughout. Photoshop's abilities to combat this amateurish presentation of an image are, like many others, reliant on selection techniques. (I remember when Thomas Knoll said to me, "If you can select something properly, you can do anything you want to it - - selection is the key." He was first showing me one of the early Beta versions of Photoshop before Adobe even knew about it some umpteen years ago.) Since photographers who work underwater are really limited to using the flash on their cameras, we'll use this photo of a horned shark as an example which was taken by recent 2-Day Photoshop Workshop participant Norm Spieler, who, in his spare time, is a serious marine photographer. Before working on the raw scan it was copied to a new layer where all the adjustments were made so that comparisons to the unaltered Background were immediate. After globally adjusting Curves to balance color the shark was carefully outlined with the Lasso tool, using the Alt key (Option key for Macs) to "rubberband," with 1 pixel feathering. This selection was then saved to a new alpha channel (Mask 1). Some people might prefer to do the outlining with the Pen tool and change their path into a selection with one pixel feathering. This is quite appropriate - I just find the Lasso tool more immediate (especially when I start creating selections with multiple featherings). The shark is outlined so it can be worked on separately and we will use the mask we just made repeatedly. Of course the key to combating flash fall-off is using Transitional Masks. Creating a transitional mask actually involves "painting" an alpha channel with the Gradient tool, usually using a Linear gradient from Foreground to Background Colors set to Black and White. This is how the Foreground Mask 2 was made. First the area to be affected is "mapped off" by selecting it with the rectangular marquee too. This selection is then saved to a New Alpha Channel. Go to that channel by clicking on it (make sure your channels window is showing and extended vertically to show all your channels). Now De-Select (Command, Control D) - a white rectangle is in the lower third of your frame with solid black above. Paint, using a Linear gradient from Foreground to Background Colors set to Black and White, vertically down from the point that black and white meet to just past the end of the bottom frame. This will create a transition from black to about a 15% grey at the bottom of the image. Now click back onto the composite RGB image channel and Load the alpha channel that was just made (you do this under the Select menu or you can click onto the channel you want to load while holding down the Control Key, Command Key for Macs). Remember that the Marquee represents the 50% density areas and lighter so it will appear that your selection starts about twice as low as it really does. It's like major feathering - the areas closer to black in the transitional mask are minimally affected and the lighter the area is the more affected it becomes so the change occurs transitionally from the black unaffected areas to the light grey most affected areas at the bottom. White areas in an alpha channel represent fully selected areas and we actually have none in this mask. To create the finalized version of Mask 2 the Shark Mask channel was loaded while holding the Alt Key (Option for Macs) down, which subtracts the shark outline from the existing selection, the transitional mask (yes, the transitional mask has been masked). Now that the bottom foreground only is selected it is easy to start adjusting its density. Using Levels the midtones and highlights were darkened and color balanced at the same time. This adjustment affected the areas towards the bottom of the frame more, equalizing the brightness from the flash nicely. The next mask for the lower right corner (Mask 3) was created with a lot of feathering. Setting the feathering in the Lasso tool to 60 pixels (this was a 12 MB scan) created a very soft division between fully affected and unaffected areas. Note that the shark outlined was also "knocked out" in this finalized mask. This area was then further darkened using Curves to balance its initial lack of density. The top area of the frame, the background behind and above the shark, was selected using the same process. As you can see, Mask 4 was also finalized by "knocking out" the shark outline. Then density and color adjustments were made as well as a Guassian blur filter to put the background more out of focus (towards the top especially). This eliminated a lot of "spotting" with the Rubber Stamp tool. A final transitional mask was made within the shark outline itself (Mask 5), since the tail side was much darker and more cyan than the head side. The original shark outline channel is first loaded then this is saved to another new Alpha Channel. Keeping the selection live this time the gradient tool was started about one-third down the body from the head to the tail (Linear gradient from Foreground to Background Colors set to Black and White) filling the area of the shark mask from black a very light grey (by going a little further than the outline). This channel mask was then loaded to the RGB composite and density and color adjustments were performed on the shark which most affected the tail end and transitionally less and less affected towards the front one-third of the body (which is fully unaffected). The finalized version of the image is seen to the right after a little Unsharp Masking was done to the shark only by first loading its channel mask.
Original Raw Scan done on a Nikon LS-2000 film scanner
Mask 1
Mask 2
Mask 3
Mask 4
Mask 5
In this finalized version of the photo density adjustments and color balancing in conjunction with the various masks shown above has evened out the flash fall-off effect allowing the subject to gain prominence. Image density and color refinements like these used to be achieved in the darkroom through masking, dodging and burning techniques while exposing the print on an enlarger. IN MEMORY OF CARL VOLK We would like to extend our deepest sympathy and
thoughts to Apogee Photo would like our readers to continue to
benefit from If you feel you have benefited in anyway or would like
to honor The donated funds will assist in sudden family expenses,
in the Please make checks payable to Claire Volk Heath: Carl's art, talents and teachings will live on for all
of us to enjoy. |
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