Wednesday, June 8, 2011

Covert pthalo

Blue poison dart frog

One of the things I noticed in the last workshop was how many people had Pthalo blue on their palettes and didn't know it. Pthalo is a powerful slightly greenish blue. I don't happen to like pthalo much, but you might. I feel it is out of step with the rest of my palette, being so much higher in pigmenting strength and that it can give an electric look that I don't particularly want in my somewhat reserved color. So I don't use it. But a lot of fine painters have and it is a permanant color. I am not opposed to modern pigments, I like quinacridone a lot, and there are a lot of great new red pigments.

BUT it is important to KNOW what is on your palette. If you are using pthalo, you need to know that. Many manufacturers either don't disclose on the tube that their paint is made with pthalo, or make it hard to figure out. Some companies force you to guess, divulging nothing about the contents of the tube. I want to use pure and named pigments. So I don't buy colors with names like astral blue or Hortensia. Pthalo is an inexpensive blue manufactured in enormous quantities. It is everywhere in the products and printed matter about us. It is also very cheap as pigments go.

Many of the colors that are counterfeited with pthalo are very expensive, like cerulean, cobalt or viridian. I give out a list of recomended colors before a workshop and suggest that they be the real thing and not a pthalo imitation. Probably half of the students show up with a thalo of one kind or another, and have no idea that is what they are using. So I asked each student if I could see their tube of viridian. Almost none of them were printed with the word hue (indicating a counterfeit) and on most of them the pigment code gave the content away. Pthalo is usually PB-7 or PB-15-3 or PB-36

Paint companies love the stuff and make a bewildering array of mixtures based on pthalo that you might not be aware are. There aren't that many blue pigments out there in the art trade and if the tube is filled with genuine viridian or cobalt, the manufacturer will be certain to boast of that on the label. Most of the proprietary blues and greens are pthalo, such as Winsor blue. If the paint is a blue or green and named something like astral blue, Sevres blue, or monastral blue, you can expect it to be a thalo based mixture. If you have any doubt or the tube doesn't say what it is, you can probably assume it is pthalo.

Sap green used to be made from buckthorn berries and I used it long ago. It was impermanent. Today, sap green is made of pthalo doctored with a little yellow. Permanent green is a pthalo color. Pthalo makes a lousy substitute for viridian, but viridian has become quite dear and as I said pthalo is cheap.

So check the small print on that tube of whelk blue and find out what you are really using.

I will be painting tomorrow at the Bethesda fountain in Central Park. If you are in the area, stop by and say hello. I expect to arrive at about 11;00 in the morning. You will recognize me because I am 6'4 and have shoulder length gray hair and I will be working on a Gloucester easel.


Brady said...

After reading this I had to go look at my viridian. It says it is hydrated oxide of chromium. I guess that's the real stuff.

The brand is W&N btw for anyone who cares.

Michael Chesley Johnson, Artist / Writer said...

I have phthalo blue on my palette, and I like it. Lately, I've switched over to phthalo green. I recommend these two phthalos to my students, but I do warn them that these are like nitroglycerine. A little dab'll do ya, as they say. But it also needs to be tempered - and this is sometimes a Herculean effort - so it's not so raw. Black helps. said...

Pthalo...the big loud drunk person at the party that gets into every conversation!

Barbara A. Busenbark said...

I have similar feelings about Prussian Blue, which I use on rare occasion and very sparingly. It doesn't live on my palette, just visits sometimes.

Libby Fife said...

I am really excited that you mentioned this. Though just a novice and "for fun" painter, I did take the time to learn about the paints that I selected. As you said, phthalos are quite widespread and I had read many times to look for pure hues. So I investigated prior to buying and found that I really enjoyed learning about paint. I also looked to see what other painters were using whose work I admired. Once I did some research, I found that the best way to learn about this is to use the paint. See what the results are and if those results fit what you are trying to say; your style and intent. So, I use phthalo blue when I paint some pieces that I want to be spring like. The grass is so green here (along with the trees) that the color, in moderation, seems to fit with the rest of what I do.

Thanks again. This particular subject really appeals to me.

jeff said...

Prussian Blue seems to made with Pthalo as well. It's not the same as the older pigment which was an iron oxide pigment developed in the 18th century.

I try to use both sparingly.

Pat Jeffers, Artist said...

If in doubt, try going to When you've found the color you are questioning, click the "item number" for specific details on it. There are two tabs at the top: a color swatch that is the default and then pigment details. You can get quite an education reading those details, including the history of the various pigments. Very handy.

Thanks again for all your posts Stape. Love your blog.

stapeliad said...

Oh!! Bethesda fountain! I am going to take a little break from the boring office and come say hello! Gosh I'd love to meet you in person!

billspaintingmn said...

Thanks for this info Stape. It's good to know the ingredience we use. That in itself is a fine art.

I hope to be able to explore and understand color better.

You shed light on so much. You have saved me years of blindly wondering, and have hinted on things to help me out.

If I can ever be helpful or useful to another, I am.
If I can ever be helpful or useful
to myself, I will.
If I can make better paintings, I'm thankful Stape.

jeff said...

I went to Blicks and clicked on the W&N Prussian Blue and it's not a Pthalo blue. Which is good.
That's a good service that Blick has.

James Gunter said...

I have tried pthalos in the past, and may try them again someday. My early experiences with pthalo blue or pthalo green was much like mariandioguardi's comment. That IS a good description! If not used carefully, those colors can make your whole painting look, well, "pthalo!" Later, I learned to tone down pthalos overbearing nature to much more manageable levels, but that took a whole lot of effort!

Johan said...

W&N Winton's Viridian Hue is indeed
phthalo green.
The problem with phthalo colors is that these are really strong pigments and before you know it, it's all over your painting.
I have them too though (phthalo blue, and viridian hue), because as you say, the really good paints are very expensive.

Michelle B. Hendry said...

As an acrylic artist, I am fairly certain that I don't have a choice. Many great pigments are 'hues'.

Back in my early painting days I had a lot of fun with the strength of Pthalo blue when painting night skies and rich abstracts with metallics, but now using a more realistic and representational palette, mixing greens in acrylics have their challenges! It's a good thing I am able to be more of a chef than a baker with my palette!

stermyn said...

No Pthalo on my palette. I just purchased an expensive tube of Williamsburg Severs Blue, it does have pthalo so if I use it I will understand this and proceed with caution. Thank you for this lesson. Hope you have recovered from hot paint out in Central Park! Nice painting of cool fountain on a sweltering NYC afternoon.

MichaelJA said...

I notice you jump between thalo and pthalo, is there a difference besides the p?