Science Buddies: "Ask an Expert"

My daughter chose "How to make the boldest, brightest tie-dye" for her science fair project from the science buddies website. After completing the experiment and creating the charts using the color picker tool, the data from the tables doesn't match the obvious brightest and boldest dyed fabric. How should she use the hue, saturation, and brightness levels to determine what is boldest and brightest?

You should use the saturation as the level of "boldness" and the brightness as brightness. When dying using one color, the hue should most likely be constant and for each graph only the saturation or brightness should change for each fabric. After keeping the hue the same and trying to pick the saturation and brightness that matches the fabric color the data should reflect the observations more closely.

This makes more sense to keep the same hue - one thing that was throwing us off is that the wool we ordered was natural colored instead of bleached, so it is a different hue, but it started off a different hue to begin with. The biggest issue is that I could redo it 100 times and get different results based on the lighting of the room, the brightness of my computer screen, the angle I am sitting at in front of the screen, whether it is myself or my daughter looking. Also, the brightness component of the color picker tool measures whiteness really, so this isn't a good description of the project if you are wanting "bright" as in "vivid." In this case, the lightest fabric that barely absorbed any dye would win the brightness contest and I don't think that is what was intended. She changed her research question to say "Which fabric absorbed the dye to create the most vibrant color?" Thank you for your help. This project turned out more difficult than we thought, mainly because of the difficulty in getting an exact match to the color on the computer screen.

Perhaps scanning the fabrics or taking a picture the the fabrics in good lighting and uploading them into a computer will help with the accuracy of the color picking because they can be compared on the same screen. You could also print and compare the different colors by taking a screen shot and pasting into a document the different color possibilities, but this way may be more tedious. If the wool is a different color it might mess up the project because the starting color has to be a control variable, meaning it has to be the same for all of the fabrics. If the wool is a shade of grey it may be fine, but if it is a beige or another color then it will affect the hue. A way to look at it is if you have a set hue and set the saturation to zero then the starting fabric would have to be some brightness of zero saturation. For the wool you can look up and see if there is a way to bleach it yourself, buy bleached wool, or if you have enough other fabrics you could just not use the wool. The brightness on the other hand does seem to be dependent of the starting brightness of the fabric. If all fabrics are the same white to begin with and the brightness does not seem to have any significance you could try keeping the brightness the same and just change the saturation (the brightness will probably be around 100). If you do this you can still include a brightness graph showing that it stayed the same and/or mention it somewhere in the project.