View Full Version : Pthalo/Thalo Colors

09-04-2004, 11:08 AM
What is the difference between Pthalo and Thalo colors? I use Grumbacher acrylics and noticed that Thalo is a registered trademark of Grumbacher. This may not be the best example but I have a Thalo Blue (Grumbacher) acrylic color and a Pthalo Blue oil color. These colors seem to be more or less the same but I'm wondering why one has a (P) in front of Thalo. Does the (P) mean something; a chemical maybe?


Brian Firth
09-04-2004, 02:29 PM
They are exactly the same color. They are just playing marketing games with the name. The best way to decipher what colors are in paint is to learn the pigment reference numbers. For instance, pthalo blue is PB15. Any reputable color will have the pigment number listed on the tube. This will help greatly in deciphering colors like Winsor or Grumbacher Red, permanent rose, etc….

Here is a great site which list almost all the pigment reference numbers and the pigments characteristics. It is four watercolors but the pigment information is universal.


09-04-2004, 03:39 PM
Yup, what Brian said. :) They trademarked the name 'thalo' just as Winsor & Newton use 'Winsor Blue' for a pthalo blue. Pthalo or phthalo is just an abbreviation of the chemical name: Phthalocyanine. Here's another page for you: http://www.gamblincolors.com/materials/blues.html

09-04-2004, 04:29 PM
Hi Dave, in addition to what Brian said Grumbacher extended the name to include other colours too so watch out for that, e.g. Thalo Crimson, Thalo Yellow and some metallic/iridescent colours.

They have PDF files of their pigments on their website if you're interested in having them to hand.


09-04-2004, 08:47 PM
Thank you, everyone. I just wanted to clear that up. When I got my acrylics, I was very surprised that "thalo" was a trademark. Go figure!


09-05-2004, 10:17 AM
Brian.. great link with lots of good info.. thanks!