I need some help, so put on your thinking caps!

[Doug Cox]

I have what I assume is a PH shift but I could be wrong. I have a dark green carpet (nylon) with a tan design and a tan carpet (nylon) with a green diamond pattern. They could be coordinated carpets from the same manufacturer. Anyway I used rust remover (for rust spots) on both of these carpets and the green dye turned a bright blue. The color didn't change when the rust remover was applied but during drying. I know what I might start with but wanted to get others opinions. So help me out guys. Thanks.

 

[diamond brian]

got yellow

 

[harryhides]

Neutralize with an alkaline - you know how the ph table works ??

 

[Doug Cox]

That was where I was going to start.

 

[Greenie]

ya know, nobody ever could fully explain why we see a color change just because the pH shifted. Harry?

 

[Mikey P]

Pre vacuuming prevents that you know.

 

[Shawn Forsythe]

Greenie,

It's due to chemical change of the chromophore in the dye molecules. All dyes are not subject to this phenomenon. And when it happens, in many cases, the reaction is reversible. It's more rare that dyes would exhibit the "problem" with acids however. If a test area shows that neutralization, or disparate pH shift to the other side of the spectrum does not reverse the process, then the subject dye can be said to be "bleached". Color loss due to bleaching can be either an oxidation and/or reduction process. pH is often the indicator of such. Reduction is commonly, but not always associated with acidic pH, and vis-versa.

If bleaching has occurred, and it can ocur with just one color element of a dye mixture, then the associated color loss can only be corrected with color repair. In this case, it is likely the yellow dye element suffered chemical change.

See the article I wrote in the Library Room on Reduction/Oxidation.

 

[harryhides]

That's what I was gonna say, Jeff.

One way to look at how oxidizers work is to take some paper ( any color ) and oxidize it with fire and it becomes mostly invisible gases.

 

[Greenie]

ok.



ps: just for the record, the student has to be able to comprehend and process the explanation or it's really not that helpful. lol

 

[Doug Cox]

If I am to use ammonia for neutralization, what is a proper dilution. Thanks

 

[GRHeacock]

Using drugstore or common household ammonia, use straight.

You CAN start with a weaker solution, and dilute by half with water, but keep some full strength.

This has worked for me many times over the years.

Gary