2007 SLP Curriculum Guide #03, Foto Enhance Brightness/Contrast and Curves
Curriculum Guide Index

Most photographs that need fixing need to be brightened. Two features, amoung others, accomplish this goal, 'Brightness/Contrast' and 'Curves'. Both of these features, as others, requires some experimentation to find the values that will bring about the results wanted. Also, for those not technically knowledgeable, the trial and error and visual evaluation will work fine in this process.

BRIGHTNESS AND CONTRAST

Brightness and Contrast will brighten and then make a picture bolder with the contrast option.

  • Version 8: Colors || Brighten/Contrast
  • Version 9: Adjust || Brighten/Contrast || Brighten/Contrast
  • Version 10: Adjust || Brighten/Contrast || Brighten/Contrast

Brightness values are from -255 to +255 or from solid black to solid white. This feature will change the brightness of the whole photograph so work first with it first and vary the values in small increments.

Contrast values also are from -255 to +255 or from gret to very bold yellow/red colors. Contrast tends to make the photograph less or more bold by decreasing/increasing the black/white values of the photograph. Again, work this feature in small increments.

However, to get a good idea of how the values will produce different results, exaggerate the values initially.

CURVES

Curves is a very interesting feature that will combine a number of different effects to fix photographs from brightness/contrast to changing the hue (colors). To learn the nuances of this feature takes both time and experimentation.
  • Version 8: Colors || Adjust || Curves
  • Version 9: Adjust || Brighten/Contrast || Curves
  • Version 10: Adjust || Brighten/Contrast || Curves
After getting the Curves window there is an Input/Output Grid in which a line between the two is seen. One can change the 'Channel' and the Input/Output values.

Channel can be set to combine all three primary color channels (Red, Green, Blue) or work with each channel separately. One firsts selects the channel to work and then varies the Input and/or Output values.

The Default values has two 'Nodes' one at the lower left of the graph line (where the Input/Output values are '0'). By clicking on that node one sees those values. The other node is at the top right and when clicking on that node the values are 255, 255. Notice that the Input/Output bars to the top/left of the graph are shaded from black to white. These end values (Output = 0 and Input = 255) give the result as the original photograph. Thus to get an idea of how things work we will be varying these values. However, first, one can ADD a node by placing one's cursor on the graph line and right clicking the mouse. To REMOVE an added node just graph it and move it off of the graph. The following are suggested steps to take to begin an understanding of how to use the CURVES feature.

  1. Grab the lower left node. (Put and click cursor over that node.) Drag the node up and notice how the values in the in the OUTPUT box move from zero (0) up to 255 and cause a white cast over the picture up to solid white. Return node to its default or 0,0 position.
  2. Grab the same node when it is at the lower left and drag it to the right and again notice this time the values in the INPUT box change causeing the picture to darken until completely black. Return node to default.
  3. Now, grab the top right node and first drag to the left, then after returning it to its default position, drag it down. Again notice how the values change.
Comment #1: One can now drag each of these two nodes to some value within the graph. In taking time and slowly moving either node one can get a nice result. Try the following: Top Right node 160,255 and the Bottom Left Node 0, 32. The result is very similar to the Auto Fixes one tried in the last guide.

Comment #2:One of the neat aspects of CURVES is one can add nodes and can get some very subtle effects or fixes for the photograph. To ADD a node place the mouse cursor along the graph line and right click. Start right in the middle of the graph (128,128). Then grab this node to make it active and drag it anywhere in the graph to see how various locations affect the results. Notice which values create a richer outlook.

Brightness - Contrast (50,40)
Third Node set to 96,160
Third Node set to 160,228

Notice how close the Brightness/Contrast picture is with the Curves Pictures. Also, notice the differences which are very subtle. In my opinion, the Curves photographs are a bit clearer and the colors are sharper. Again, take your time to explore these two features, particularly the Curves feature. Experiment with different values and with additional nodes. Curves, though a bit more complexe than other features, has some very nice advantages and one learns how to place nodes and set their values.

ACKNOWLEDGEMENT

  1. When completing a tutorial or series of tutorials, and having placed them upon your web page, post in the SLP Forum your completed work using this layout:
    • Name or Screen Name.
    • Web Site URL.
    • Version of PSP using.
    • List of Tutorials completed.
  2. Post your Work:
    • List what you did, feature, options used, values.
    • Indicate steps taken and results.
    • Indicate things you found interesting, worthwhile and any other comments.
  3. List some of the similarities you found between the Menu System, Palettes, and Keyboard shortcuts.
  4. Post any questions and comments in the SLP Forum.

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