can I use paint for science fair project

[momweber]

Hi, my dtr wants to do a science fair project that compares different detergents and effect on stain removal. Her teacher liked the idea but said it needed to be measured accurately, not just eyeballing the differences. Somewhere online someone commented that this could be measured by taking digital photos of each fabric and importing into Paint and using Paint to " find the average of the RGB values to see which one is lightest". I have no idea what this means or how to do it. Any help would be greatly appreciated.

 

[mickey megabyte]

hmm, well i certainly wouldn't use paint (as supplied with windows 7), it just isn't sophisticated enough to display rgb values.

you could use the freebie (and very goodie paint.net) to do the job, though.

ok, let's now explain RGB values:

in simple terms, colours on a computer can be measured by their rgb value - how much red, green and blue there is. each of these colours is given a number, generally between 0 and 255.

so a bright red would be 255,0,0 because there is a lot of red with no green and blue, whereas a bright yellow would be more like 255,255,0 as there's lots of red and green but no blue.

pure black is 0,0,0 and white is 255,255,255. a bright clean t-shirt (for example) would be closer to the high end than a dirty one (if they were the same colour to begin with, and were photographed under the same light conditions.)

you could take photos of shirts, load these photos up in paint.net or similar powerful photo-editing program, and use a tool to measure the rgb values of the photos.

however, i'm not sure if it's truly an accurate way to determine dirtiness...although it may do for a simple school project.

i've tried to keep it simple, and i hope i've explained things well.

do post back for more help or info.

oh, and welcome to sevenforums!

 

[momweber]

thank you so much! Your explanation was so simple to understand. I downloaded paint.net and have searched how to assess the RGB values and couldn't find answer so posted my question on forum there. Hopefully someone over there can help us with this. I really appreciate you taking the time so write such a thorough explanation of the RGB values. My dtr will be able to use that description in her write up. Have a great day!

 

[HammerHead]

Gimp

Gimp might do it. It's worth a look see. Search "Gimp" its free.

http://www.gimp.org/

 

[Dwarf]

I've just checked, and Paint (the one included in Windows 7) will do the job perfectly well.

Open the image in Paint and click on the Color picker under Tools (middle icon on the bottom row). Now click on the spot in the image that you wish to analyse. You will notice that Color 1 will change and will now be the same color as the spot you have just clicked on. To find the RGB values, just click on Edit Colors.

The example below shows an enlarged version of my current Avatar, with part of my hat selected for the colour.



If doing this scientifically, you will also need to include a reference for correction purposes. A piece of white card will do the trick, so long as you use the same piece on each sample. Since you know that the RGB of white is 255 255 255 you can use this to correct the other measurement.

 

[mickey megabyte]

i'm glad i could help, momweber, there are many ways of doing this,and paint.net was the first tool that came to mind.

you need to use the colour-picker in paint.net.

first, click the 'More>>' button in the colors box.

then select the color picker tool (next to the pencil).

then when you move it over the image, and click certain points, the rgb values will be displayed.

ask if you need more help.

 

[momweber]

Thanks so very much for showing me that! That is exactly what I was trying to figure out. Don't know if averaging the three values would be scientific in determining whiteness but it looks good to me. I appreciate you help on this! Take care.

 

[mitchell65]

Mickey hit the nail on the head when he said "and were photographed under the same light conditions", that's nearly impossible to achieve unless you have studio facilities. You could always scan a flat section of the shirts. At least the light source would be the same. And by the way, don't forget that if one shirt looks cleaner than another one, then it probably is