"I
do not object to retouching, dodging. or accentuation as long as they
do not interfere with the natural qualities of photographic technique." -
Alfred Stieglitz
"Sitting
over a hot computer ain't my idea of fun. My creativity goes almost
completely into picture taking. (But) I suppose if I ever retired, I
would enjoy learning the Photoshop craft far more than playing golf." - Herbert Keppler - On going digital. (Popular Photography & Imaging, January 2005)
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| © Andric |
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| © Andric |
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| © Andric |
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| © Samantha Everton |
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| © Samantha Everton |
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| © Samantha Everton |
Understanding the Digital RGB #s
To have an understanding of Photoshop, you must first learn how the program "sees" your image. The most basic picture element
of a digital photograph is a "pixel" and an image is made up of a lot
of these. Photoshop simply manipulates the color, tone, and position of
these pixels in order to achieve the photographer's desired results.
But before you start retouching, I want you to understand how the colors
and tones of each pixel are interpreted by Photoshop, and ultimately by
you as a Photoshop user!
As
in photography, it all starts with light and specifically the mixing of
3 primary colors together to achieve all the other colors we can
possibly see.
The Additive Process involves mixing Red, Green, and Blue light together
in varying proportions to produce any color. The RGB color method is
used in today's digital camera sensors, television sets, and computer
monitors, and was was used in early color film photography. Adding
red, green, and blue light together in equal amounts will produce
white light. Mixing just 2 of the additive primaries together will
produce one of the subtractive primaries (see below).
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| RGB = Additive Primaries (CMY = Subtractive Primaries used in printing along with black or K) |
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| Equal amounts of RGB light mixed together = White light |
Most of the color images you will be working on in
PS are 8bits/channel. Your images have 3 total
channels -- Red, Green, and Blue, which can be viewed independently in
the channels palette and in the info palette. And 8 bits when multiplied
by the 3 channels gives you a total of 24bits of information per pixel,
or 16.7 million colors. This is known as the bit depth, or color
depth, of your image and describes how many colors each individual pixel
can have!
Back
to 8bits/channel though, which is to say 256 tones/channel. This gives
you a tonal scale of 0 to 255 for each channel (Red, Green, and Blue). When all
channels are set to 0, and turned off, you have a black pixel. All
channels turned on to 255, results in a white pixel. And as long as the RGB
numbers are equal, you are looking at a neutral gray pixel (darker if
the numbers are closer to 0 and lighter if they are closer to 255!).
The
RGB numbers for each pixel in your image can be viewed in the Info
Palette, and the information can be used in Levels or Curves to properly
balance the color and tone in your image. In fact, having an
understanding of these numbers is one of the most useful things I can
teach you in this class. With this knowledge, you can almost guarantee
yourself proper printing results and accurate color with most of your images.
Please take a look at the below handout for more information on RGB numbers:
Editing Selections:
Standard Mode
= Once a Selection Tool is used (such as Magic Wand or the Marquee
Tool), "marching ants" display your selected area in the image window.
Add to a selection = Shift key (or choose the "add to selection" button in the Options Bar)
Subtract from a selection = Option key (or choose the "subtract from selection" button in the Options Bar)
Quick Mask Mode = (icon just below Foreground/Background colors in the Tools Palette) Visual color overlay of your selection - useful to view how soft or hard your selection edges are. (Switch to Quick Mask Mode by clicking the button at the bottom of the Tools Palette)
Add to a selection = with Brush Tool, paint with White in image window
Subtract from a selection = choose Brush Tool with Black as foreground color
Select > Refine Edges – to refine Selection Edges, or to refine the edges of a Layer
Mask!
·
Radius = Increasing will improve the edges in areas of
soft transitions (similar to Feather)
·
Contrast = Will make soft edges crisper and remove
artifacts along the edges of a selection
·
Smooth = Will smooth out jagged selection edges (Use
radius to help restore some of the detail)
·
Feather = Will uniformly soften the edge of the
selection and help produce a soft edged mask
·
Contract/Expand = Shrinks or Expands a selection size
Select > Save Selection to save a selection as an Alpha Channel
Select > Load Selection to load an Alpha Channel (simply reselects a saved selection)
Select > Color Range
to select similar colors within the entire image
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| How to properly adjust for color and tone with a Curve Adjustment Layer |
