Is white on white usually weaker than other blotter?

guess ya got me...

 

Nope, because it's an erroneous assumption with absolutely NO science to back it up, actually quite the contrary is true.
Color gives NO indication of purity. That can only be determined by proper lab testing.

 

This is silly.

Color can be effected by a number of things, including what types of washes and cleaning up of the product was done in the end. You can't tell how pure something is just by looking at judging by the color though, that is 100% correct. You can have LSD that has oxidized and it will turn from white to brown/black. It will still get you completely fucked up and really isn't any less pure. Even one chemist remarks in DMT: The Spirit Molecule about how his first successful LSD synthesis came out black(It started oxidizing right in front of him during crystalization). He states that he ate this LSD and thought he wouldn't get any effects only to sit and realize he had succeeded.

By the way Gas, I've been able to tell different batches of crystal apart without being told they were different. I was only told it was different on several occasions after I ate it and shared my opinions. I only associate with friends, no one needs to sweet talk my ear or talk anything up. My expectations have played no role and I do consider set and setting when it comes to analyzing a trip. But then again, I often eat L in the same set and setting and after eating it hundreds of times, its pretty easy to have a really familiar and comfortable relationship with the experience.

Just like with everything in life, it seems the truth constantly lies in the middle of both sides of the disagreements here.