PCCI: Adobe Photoshop for Photographers, Day 2
Definitely having a fun time. For one, I am learning new things in which I am interested. At least, even for a few days, will forget about work and the pressures of the merger.Back to my notes...
TONAL ADJUSTMENT
a) Adjust exposure
b) Contrast--if low contrast, image is flat
HISTOGRAM shows how the brightness of the image is distributed. When looking at histograms, you do not want sparks at both ends.
ADJUSTMENTS:
a) Auto-Contrast
b) Auto-Level
c) Curve's Auto -- In the Options, similar to auto-contrast if "Enhance Monochromatic Contrast" is chosen, similar to auto-levels if "Enhance Per Channel Contrast", and auto-color of "Find Dark & Light Colors".
d) Equalize -- Balances light and dark.
LEVELS
1) When adjusting the sliders, press the ALT key.
= When moving the left slider, stop when you see a color/black appears.
= When moving the right slider, stop when you see a color/white appears.
* The Output Levels determine the shadow and highlight that can be printed by the printer.
Minimum Highlights for Publication:
Newspaper -- 5%
Magazines -- 3%
High-End Brochures -- 3%
Maximum Shadow for Publication:
Newspaper -- 75%
Magazines -- 90%
High-End Brochures -- 93%
2) Another way is to use the sampler (limited by the output levels).
= Press ALT while moving the left slider to the right, get color sampler for the shadow.
= Press ALT while moving the right slider to the left until white appears to get the color sampler.
= Double click the Eyedropper/s to adjust the Output Levels based on what the printer can print, e.g. if printer can only print 10 for shadows, put 10 in R, G, and B; if printer can only print 245 for highlights, put 245 in R, G and B.
3) Another way is to use Threshold in the Adjustment Layer. Threshold is used to determine the shadows and highlights by using New Fill or Adjustment Layer. Move the slider to the left. Slowly move the slider to the right until black appears. Mark the shadow by pressing SHIFT-click on the image. Move the slider to the rightmost and slowly move it to the left until white appears. Mark the highlight by pressing SHIFT-click on the image. Use the appropriate eyedropper to color sample using the "marks" or "guides" on the image.
* The middle slider is for the Midtones that can lighten or darken the overall image.
CURVES
* Press ALT-click to switch to a fine or big grid.
* Click on the graph to mark a point. You may use the UP and DOWN ARROW keys to adjust.
* Tonal adjustment is somewhat sharpening the image.
* Another way to mark the graph is to go to the image and press CTRL-click on the part of the image you want to improve.
* There can be several marks in the curves to adjust for the highlight and shadows. Temporarily use Threshold in the Adjustment Layer to look for the shadows and highlights.
* An S-curve adjusts the contrast. The steeper, the higher the contrast.
* If the color has been affected and you just want to adjust the brightness and contrast, use Luminosity Blending Mode.
ADJUSTMENT LAYER:
* Non-destructive
* Opacity control--to reduce the effect
* Blending mode -- e.g. luminosity
* Layer mask--limit the effect of the adjustment
* For OVEREXPOSED IMAGE, copy a layer and use Multiply Blending Mode. Best is to make an adjustment layer and Multiply (copying a layer increases file size; adjustment layer does not increase file size).
* For UNDEREXPOSED IMAGE, do a selection you want to lose the details by creating a mask. Inverse selection, create Adjustment Layer, Screen Blending Mode.
* You may use gradient for mask.
* Blending Mode Hard Light increases contrast; can be combined with levels. Soft Light and Overlay Blending Modes can also be used for contrast.
SHADOW/HIGHLIGHT
* Improve shadows.
* Used for back-lit images.
* When the picture "flattens" as you lighten the shadow area, click Show More Options in order to adjust the Tonal Width and Radius. When you adjust the Tonal Width, you specify the area around the shadow (affecting midtones, etc.). The same is true for the highlights to adjust overexposed areas of the image.
* If you want to improve SELECTIVE SHADOW, use Layer Mask.
a) Duplicate image.
b) Screen Blending Mode.
c) Create Layer Mask (press ALT+Add Layer Mask).
d) Paint the area you want to adjust.
* Another way to improve SELECTIVE SHADOW is to use History Brush.
a) Copy background.
b) Blending Mode Screen.
c) Right click on new layer to Merge Down.
d) Put History Brush in History Palette's Merge Down.
e) Click History Palette's Open.
f) History brush on the area of the image you want to improve.
(SELECTIVE) DODGE/BURN
a) Create A New Layer (press ALT-Create A New Layer) where a dialog box will appear. Change to Overlay Mode and check the Fill With Overlay Neutral Color (50% Gray).
b) Perform dodge or burn on the new layer.
(SELECTIVE) COLOR RANGE
a) Use Select>Color Range to choose the highlight, or shadow; then Copy To A New Layer (CTRL-J).
b) Adjust using the new layer.
c) Don't forget to Feather selection.
* To select the luminosity of the image, CTRL-ALT-1 (for older version, CTRL-ALT-~). Feather (CTRL-D). Copy to a new layer (CTRL-J). Blending mode.
* NOTE: Always Feather after making a selection.
EXPANDING THE DYNAMIC RANGE
* If the image to be taken exceeds the dynamic range of the camera, take two images.
* In Photoshop, combine the two images with one images as the Layer (press SHIFT while moving the other image to align). To check if the image is aligned, use the Blending Mode Difference. If there's a white on the edges, the image is not aligned. Then, Add A Layer Stlye. Adjust Blend If's This Layer by adjusting the slider in order for the image below to come up. For smooth transition, split the slider by pressing ALT while moving the slider.
NEUTRAL DENSITY
a) Be sure foreground/background color is black and white.
b) Create Gradient Map Adjustment Layer and choose gradient type.
c) Blending Mode Overlay.
d) Double click on the new layer then double click gradient to open Gradient Editor.
e) Adjust gradient by moving slider for opacity or color.
posted by ~GFA~ @ 4/24/2007 08:22:00 PM
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