[Physltest] [Phys-L] Re: Color (was LED mini-flashlight price break)

[Bernard Cleyet <anngeorg@PACBELL.NET>]

The chem. teacher * at N. Salinas HS offered me one of their New (still
in box) student spectrophotometers.  Next time I'll know better.  Monday
I'll get one and do the food colors + those GK plans to buy.

The red is reds (FD&C) 40 and 3;  the others are unlabeled (boxes tossed).

This would be a great student project:  add watercolors, bio. stains, etc.

* appreciates my demos, stuff from RAFT, and the surplus from the U's

bc

John Denker wrote:

> Bernard Cleyet wrote:
>
>
> > I've checked two food color dyes w/ my star.  The red has a very sharp
> > cut off at 600 so has a bit of orange and all the red to 700 where my
> > eye fades out.  The blue is interesting; it's only ~ 50 nm wide ~
> > centered on ~ 460 + it passes > 670, so it looks a bit purplish.  I
> > haven't bothered w/ the orange and yellow, yet.
>
> Very cool.  I would love to see spectra for the common
> FD&C colorants.  I tried googling for them with less than
> satisfactory results.
>
> If anybody can obtain the data, and send it to me, I'll
> plot it and put it up on the web.
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