Manipulating Digital Pictures with SplitColors Software
Purpose: Provide the freedom to explore how colors from an image can be modified to make very unusual variations of the original.
Use the analysis tools and histograms of the color intensities of the original and resulting images to determine why the new image looks the way it does.
NOTE: The images that follow are not interactive. Please download the software (OSX OS9 PC) and follow along with the mini tutorial.
Getting Started
Click 'Select Picture' to open a picture (a jpeg, gif, tiff, pict, or pdf file). A menu will pop up that lets you select a picture on your computer.
Basic Features
Move the cursor across the picture, and the pixel being displayed will have a highlighted border. The intensity of red, green, and blue that make up the pixel's color will appear in text in the lower right of the window.
'Show Original Picture’ opens a window containing the image with the original color settings. Moving the cursor in this window or the one in the main window lets you see pixel colors of both the original and new images simultaneously while the pixel location in each image is highlighted.
'Plot Histogram of Colors' creates a graph of the frequency of color intensities within 5% increments observed in both the image being displayed and the original image. For example, for a 500-pixel image, if there were 200 pixels with red intensity between 80 and 85%, the frequency is 200/500 or 40%.
Ways to Change Colors Quickly
This program allows you to display one color, such as green, in the computer's red color.
To do this, locate the menu button associated with the Red computer display color. It should have "Red" displayed if you are working with a newly opening picture and select "Green".
Set the remaining picture colors to ‘None’.
Click 'Apply New Colors to Picture' and observe how the image changes.
You may display any color of the image in any of the computer's colors (red, green, and blue).
'Invert' reverses the intensity of the selected color.
The most intense color will appear very dark on the image, and vice versa.
If you apply this to all three colors when mapped into corresponding colors, you create a color "negative" - what you get back from the photo shop when you take your film in for developing.
Stretch, Compress, and Shift of Color Intensities
You may want to display only a portion of the range of a color's intensities, and display it in the same range of the computer's color. Or you may display it however you would like - in a different color altogether, in the same range of values but more or less intense than before, or over a larger or smaller range than selected.
Use the color histogram plots to decide what ranges of colors you would like to focus on, and make your selection using the minimum and maximum value options in the top center of the window. Either type the intensity values in the white boxes or use the small up and down arrows to change values.
Checking the 'Mask' box changes the intensity of the image's color that fall outside selected range to be set to 0 (zero).
To see how the image changes, click 'Apply New Colors to Picture'.
Examples
Stretch: Display the Picture’s 20 to 50% red intensity in the Computer’s 0-100% red intensity range.
Compress: Display the Picture’s 0-100% red intensity in the Computer’s 80-100% red.
Shift: Display the Picture’s 20 to 50% red intensity in the Computer’s 70-100% red intensity range.
Save your new images. NOTE: make sure to give the saved file a different name from the original - it will delete the original!
|
