I’m sorry that I parsed your comment incorrectly.

I, too, am a big fan of blues. That’s one reason why I buy paint from Robert Doak, whose blues are unique and wonderful. I would hate to do without them.

In most cases, extenders are added to paints for exactly the reasons you specify. With very strongly-tinting pigments, however, another reason may be to make them easier to mix with. The idea of adding your own extender in this case is a good one.

And thanks for the kind words. I appreciate your participation here. Please keep doing so.

In regards to my statement concerning pthalos vs. ultramarine, I didn’t mean to show favor over one or another pigment but I instead was trying to point out that there are other reasons for choosing a pigment besides the hue and that as artists that gives us more ways to create artwork! I love all the blue pigments….I love blue! I dont think I could consider deleting any of them from my pallete.

Also the colorless extenders you mention in the article above are commonly added to paints to displace the amount of pigment and thereby reduce the cost of manufacturing. Some of you that find a paticular pigment too powerful might consider first mixing it with some sort of colorless medium to reduce it’s potency then using this resulting mixture to add to the main color your wanting to modify!

P.S. I love your website! I like the practical approach that is rare to find in most art related forums!

If pthalos work for you, then you should certainly use them. I would not substitute ultramarine for most varieties of pthalo blue, as they are distinctly different in hue. Prussian blue works very well for that purpose, however.

Did you mean fugitive? Historically, there have been a number of slightly different ways to manufacture Prussian/Milori blue. Some variants have tended to fade. It’s my understanding, however, that modern versions of the pigment are acceptably lightfast. See my response to Dorothy, above.

If it works for you, then great. I find pthalos much too strong.

Great to hear from you. I’ve enjoyed your blog (it would be great if you’d post more often—hint, hint).

Your point regarding Prussian blue is a good one. The ASTM rates Prussian blue as having the highest lightfastness rating (excellent or I). They are usually very reliable for tests of this sort. There is a good discussion of Prussian blue as a watercolor pigment at the excellent Handprint website:

(http://www.handprint.com/HP/WCL/waterfs.html

In summary, the author’s lightfastness tests indicated that some brands show a slight discoloration within two weeks, but no fading after that. Other brands demonstrate no fading at all.

Generally (but not always) pigments display their worst lightfastness in watercolor and show much better results in heavier media such as oil and acrylic. Overall, I am very comfortable using Prussian blue from good manufacturers in those media. I’d be more careful with watercolor, but it seems that the better brands produce good results in that medium as well. I don’t have any in raw pigment form and would be very careful about selecting the company I purchased it from if I did.

I don’t care to use the pthalos, either. I don’t even own pthalo green.