Title: P' 1
1Photoshop Basics
2Luminous Range
- To retain the highest range of luminosities at
EACH conversion.
3Luminous Range
- Use the best image sources
- IF possible scan to 16-bit greyscale
- Ensure scanner settingsdeliver a histogram
showing even distribution over the full range. - Scan the image
- to the highest
- resolution
- you can
4Colour
- The colour that you SEE is influenced by
- Any funny desktop coloursor artificial light
5Resolution
- In the real world, the resolution that we achieve
is governed by - Focus
- Resolving power of lens
- Camera Shake
- Heat Haze
6Scanner
- Always control the dynamic range of each colour.
- Never over-saturate.
7Conclusion
- Never throw information (colour or resolution
away) unless CROPPING
8All pictures are composed of pixels
9All pictures are composed of pixels
10Binning and Histograms
First count the number of black pixels
11Binning and Histograms
Next count the number of dark grey pixels
12Binning and Histograms
Repeat for all shades of grey
13Binning and Histograms
Note the fact that, as there are equal numbers of
shades 1 and 2, this produces a flat top
mountain.
14Histograms
- In Photoshop there are 256 bins per colour (R,G
and B) represented over 256 pixels. - In a typical picture there may be 3M pixels and
this is represented by the area of the histogram.
0
255
3M
15Some Typical histograms
NormalCentre weightedClearly drops to zero at
both ends.
16Some Typical Histograms
High KeyLight end weightedBut still clearly
drops to zero at both ends.
17Some Typical Histograms
Low KeyDark end weightedBut still clearly drops
to zero at both ends.
18Perfect Exposure
Data in the histogram is totally contained within
the box at light and dark ends.
19Perfect Exposure - Highlights
- The acid test of perfect exposure is that fine
detail is revealed in the highlights when the
light end of the curve is pulled dramatically
down. - The bias of the histogram shifts to the dark end.
20Perfect Exposure - Shadows
- The acid test of perfect exposure is that fine
detail is revealed in the shadows when the dark
end of the curve is pulled dramatically up. - The bias of the histogram shifts to the light end.
21Over Exposure
Data in the histogram is clearly off scale at
light end.
22Over Exposure - Highlights
- The acid test of OVER exposure is that fine
detail is LOST in the highlights when the light
end of the curve is pulled dramatically down.
23Under Exposure
Data in the histogram is clearly off scale at
dark end.
24Under Exposure - Shadows
- The acid test of UNDER exposure is that fine
detail is LOST in the shadows when the dark end
of the curve is pulled dramatically up.
25The Perfect Image
- The histogram (Combined Luminosity) would look
like this
26The Perfect Image
- The RED histogram would look like this
27The Perfect Image
- The GREEN histogram would look like this
28The Perfect Image
- The BLUE histogram would look like this
29The Im-Perfect Image
30The Im-Perfect Image
- Contrast Rangetoo BIASEDto High Key
31The Im-Perfect Image
- Contrast Rangetoo BIASEDto Low Key
32The Im-Perfect Image
33The Im-Perfect Image
- Low Key,High Key butLow Contrast
34The Im-Perfect Image
35Too Much Flash
Open the picture of too much flash
36- Copy the photo layer
- Change the layer mode from Normal to Multiply
37Layer mask icon
- Add a black layer mask
- Press Alt Key and click the Layer Mask icon
- Change Foreground colour to white.
38- Choose a soft edged brush, paint over the
foreground area in the photo
39After
Before
40Fixing Underexposed Photos
41- Duplicate background layer (Control-J)
- Change Blend Mode from Normal to Screen. This can
lighten the photo
42- It still not properly exposed.
- Copy the layer until the exposure looks about
- right (by press Control-J)
43After
Before
44Dodging and Burning Done Right
- Add some highlight of the temple
- Darken the water and sky
45- Create a new layer
- Change the mode to Overlay
- And click the box fill with Overlay-neutral
color
46- Switch to Brush tool, choose a large soft-edged
brush, go to options bar and lower the Opacity to
approximately 30 - Change the foreground color to black (or press
d) - Paint over the areas that you want to darken
- Change the foreground color to white (or press
x) - Paint over the areas that you want to do
lightening
47(No Transcript)
48QUESTION AND ANSWER
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