Good program to test "color accuracy" of photos?

imjtblanton · July 3, 2020

So I've got kind of a complicated, strange question. Thought this might be a good place to ask it. I was planning on testing a number of clear matte spray sealants to see which one was the best. I was going to paint some colored squares on a swatch, and take a "before" picture of it. And lock down the camera and lights. Then spray the swatch with the sealant and take an "after" picture. Do the same thing with all of the sealants with their own swatch.

Ideally the colors on the before and after swatch should look identical. Same saturation, brightness, etc. Whichever one changes the colors the least would be the best sealant. I know there's programs that test monitor accuracy and spit out some overall numbers. I think they test things like the percent convergence between the colors. Is there a program that would give me something similar if I had it compare two pictures? I could just sort of do an eye test, but would prefer something a little more objective. Any suggestions would be appreciated!

zeusthemoose · July 3, 2020

I dont know any programs, but you could use an eyedropper tool to get the rgb value of the color and compare them.

Adorable Cat · July 3, 2020

You could use just a normal image editor like GIMP and use the color picker tool, pick a spot and look at the exact color values with both images.

ofc all this is also at the mercy of how good of a camera you're taking the pictures with in the first place

imjtblanton · July 3, 2020

10 minutes ago, zeusthemoose said:

I dont know any programs, but you could use an eyedropper tool to get the rgb value of the color and compare them.

Yeah, I thought of using a eyedropper tool, but I'm not sure how I'm going to ultimately determine which colors are "closer" in an objective sense.

Say the true color is Red 150, Green 77, Blue 204. Sealant 1 changes colors to Red 145, Green 79, Blue 207. Sealant 2 changes the colors to Red 153, Green 74, Blue 202. How exactly am I going to say which one is better? I guess I could see how much each color changed for red, green and blue and add that together. So sealant 1 in my example is 5+2+3=10. Sealant 2 is 3+3+2=8. Sealant 2 wins. Maybe that works? Was just hoping some program could give me something similar to the percent convergence values given for monitor tests.