The Histogram Tool is used to analyze photos and images before making adjustments to them. The histogram displays a graphic distribution of blue, green, red, hue, saturation and lightness values of an image.   Histogram Basics The histogram is is a bar graph used to plot this series of data. In technical terms it is a graphical representation of the color values in an image. To illustrate how this works make sure the Histogram Window is active - indicated by the black and white button on your toolbar. You can see the different color values move on the graph as you draw in other colors in an image. All we need to know is that a Histogram is a graph of the colors in an image. The graph will show how colors and luminance are distributed, depending on what you have chosen to see. The histogram can also read an image's color cast. If one graph is way off in relation to the others, you know the image has color cast in that particular color. To analyze an image using the Histogram, use any of the following to display or hide the "Histogram Window" Click the toggle Histogram Window Button on the tool bar Select View>Toolbars and select or clear the Histogram Window check box Right click any palette and choose Toolbars from the menu and select or clear the Histogram Window check box Right click any palette and choose Histogram Window from the menu The following options are available under Colors>Histogram Functions: Equalize Histogram function will attempt to flatten the Histogram, by dispersing areas of color that are of equal brightness, smoothing out the image brightness.   Stretch Histogram function will modify the image so that it covers the entire spectrum of brightness making the brightness appear to be spread more broadly across the histogram (it includes black and white basically) if it does not already contain black and white (therefore it will not appear to do anything to many images). *Note: these commands have limited capabilities, if an image is really bad they will have almost no effect. Changes to the image using gamma correction as well as adjusting the highlights, midtones and shadows may be required to achieve the desired result using the histogram as a guideline. Note: Paint Shop Pro may seem to run slower with the histogram window open as it uses system resources to update the image as you change it. A bad histogram would look like the sample below. This image would be too dark. The histogram shows that the values of the graph do not go all the way to the right Histogram Window in Paint Shop Pro 6 Histogram Window in Paint Shop Pro 7   This image would be too bright Histogram Window in Paint Shop Pro 6   Histogram Window in Paint Shop Pro 7   The "ideal" histogram will have a better distribution of the values   Histogram Window in Paint Shop Pro 6 Histogram Window in Paint Shop Pro 7   Lesson Plan Now that we have covered the basics of histograms you are ready to go have some fun. Here are some online tutorials. Please submit at least one tutorial result to the group or you can submit one for each tutorial.   Ansel Adams Like Photos: http://loriweb.pair.com/8anseladams.html Jasc Histogram Adjustment Tutorial: http://www.jasc.com/support/learn/tutorials/archive/paintshoppro/histogramadjustment.asp?pg=1 Jasc Fixing Flash Photos: http://www.jasc.com/support/learn/tutorials/archive/paintshoppro/fix_flash_photo.asp?pg=1     Bonus   Histogram and Its Uses:  http://www.math.fau.edu/Pina/PhotoCorrection/hist1.html Fixing Flash Photo: http://www.jasc.com/support/learn/tutorials/archive/paintshoppro/fix_flash_photo2.asp?pg=1       Using Histograms Information: http://www.shortcourses.com/how/histograms/histograms.htm   Lesson Submittal Please remember to resize your final image so that it is no larger than 350 pixels on the largest/longest side. Please name your results as:  Your name - histogram1 (for tutorial 1) Your name - histogram2 (for tutorial 2) Your name - histogram3 (for tutorial 3) Submit your results to the group at http://pspimaginarium.com/forum   ::Index:: ::Intermediate Series:: ::Glossary:: ::Short Cut Keys:: ::Resources::   Copyright © 2000-2004 PSPImaginarium All rights reserved. Unless specifically made available for download, no graphics or text may be removed from this site for any reason without express written permission from PSPImaginarium Paint Shop Pro is a registered trademark of Jasc Software, Inc.