Pthalo Blue

Hallo, watercolour fiends.... A colour I use quite a lot, and had in a large tube, is Pthalo Blue. That tube has at last squeezed its very last drop onto the palette, and I want to replace it, and for economy's and convenience's sake would like to do so in as large a tube as possible. The small snag is - I know it's not a huge one, because no tube is going to be THAT different from another - that my old tube was VERY old: Daler Rowney's Monestial Blue, to be exact: so not "red shade", or "green shade", or any other shade: just plain ole pthalocyanine blue. I think what I want as replacement is probably Pthalo Blue green shade: but is there anyone out there who remembers the old colour, and can recommend the nearest to it that you can currently get? It's not a big issue, but I'm picky ... any suggestions appreciated.

Thanks for replies, and I await Alan's testing results with interest. I agree about the information available on the D-R site as opposed to W & N. Winsor Blue is indeed Pthalo blue by their own brand name (and the green and red shades are, apparently, merely variants on the basic colour). From what I've read in the past, the closest to the old Monestial Blue is PB (Green shade) - but I can't remember well enough to be sure, which is why I was hoping someone with direct experience might be able to steer me in the right direction. If you take a colour like Cerulean Blue, the chemical composition will be identical - but the strength of colour varies by quite a bit between manufacturers; the same is true for the pthalocyanines. Like Prussian Blue, Pthalo Blue and Green are dyes, so they will indeed stain and are a problem to lift - certainly when used un-mixed and have had a chance to sink into the paper. Prussian Blue is duller than Pthalo, in my experience - just as good in mixing, but on its own a somewhat sombre colour. It's also SAID to fluctuate in strength according to the light conditions - I'm not so sure it actually does. So, I've got the technical information - although it does no harm at all to repeat it here for others' benefit - but technical information isn't quite the same as actually knowing the paint intimately. Jackson's make their own Pthalo Blue, without red or green variants, and its chemical composition is the same (there's no reason to make a Hue of the pthalocyanines, because they're very cheap) - but it may not be close enough for my liking to the old DR Monestial. A really good Pthalo Blue will have an almost startling intensity, and be fresher than Prussian. But it does seem that you have to be a bit careful whose blue you buy - and that's true of all the others, as well: I've used some horribly weak Cerulean, for instance, and some frankly crude Ultramarine - yet the Pigment Number will be identical with other brands. (I think I'll buy a tube of the Jackson's Professional anyway, just to see how it behaves - but, Gentle Reader, I will still value your opinions and judgement.)

Manganese Blue is generally unobtainable now - in its true form. You can get a colour called Manganese Blue, but it's nearly always going to be a variant of Pthalo Blue (so is Transparent Turquoise) - generally speaking, whatever the name of the colour, if it's cheap it's a variant of Pthalo. The variations are enormous (hence my question). Syd: yes, these are dangerous colours - very, very strong whatever medium you use, and particularly dangerous in watercolour because before you know where you are you've got a blue so dark and so invasive that it dominates everything (I find the Pthalo Green very difficult to use in any medium, especially oil and watercolour; in these two media I much prefer Viridian - and you need to check THAT'S the real thing, and not a Pthalo, as well). So why use them? Because dangerous though they are, they give darks that are difficult to obtain in any other way: and if you're looking for a really strong blue or green, Pthalo and to a lesser extent Prussian will give it to you. Otherwise, you're having to use very heavy concentrations of Ultramarine plus a brown (which is fine, but gets predictable) and having recourse to such colours as Indigo (again: nearly always actually Pthalo!, plus black or Paynes), Paynes Grey, or even black. And I find these just as hard to handle as Pthalo/Winsor Blue, and a bit duller to boot. You can calm Pthalo Blue down a lot by mixing a little Cadmium Red with it - and it helps if you work wet in wet - if the paper's wet, the blue is that much easier to control. I'll let you know how I get on with Jackson's Pthalo, when I get round to ordering some.

As a matter of interest, this one was painted using Monestial/Pthalo Blue, in the greenery and also in the sky.

That's interesting - I shall read it when I've woken up properly (******* arthritis woke me up early, and I couldn't get back to sleep but am not properly awake either!). The location of that painting - there's another very similar to it but with some preliminary drawing, which I didn't employ at all in the one above but just went in with the brush - is somewhere on the South Downs; I remember my brother and sister in law driving me out there, but all I know about exactly where it is is that Petworth House isn't that far away.... Direction, sense of, never was my strongest point: I once got lost in my home village.....

I've read the Wet Canvas forum board now - apart from a slightly off the wall suggestion that Monestial Blue might be a cobalt oxide, which it certainly isn't, it's clear that others have found considerable variations in Pthalo/Winsor/Thalo/Pthalocyanine/Monestial/Monastral Blue, even though it's exactly the same chemical composition. Probably what I'm really after (and I have to concede most people just wouldn't make this much fuss!) is Daler Rowney artists' quality Pthalo Blue Green Shade. I shall be greedy, and order the Jackson's PB and the DR, and compare the two.