Tuesday, 25 July 2017

QoR Watercolours by Golden - 24-colour set

I've recently obtained the 24-colour set of 5-mL QoR watercolour tube paints by Golden. Golden sells a number of paints and mediums under the QoR branding and they sell a number of sets - to be honest, I'm not convinced by some of the sets - who wants a "high chroma set" that doesn't have a proper blue? At least sell warm and cool triads, for example. You can also buy the loose paints, but they're not cheap. This 24-colour set cost me about US$80.00, which is about £60.00 or so - that's not THAT bad at £2.50 per tube, I guess, but I'm aware buying them as open stock or buying them in a lot of European countries is VERY costly. The 6-tube sets on Amazon UK sell for an equivalent of over £4 (US$5.20) per tube, which is a LOT. I got this set from Amazon USA where the price was more economical - I've not seen the 24-set for sale in the UK but on the basis of the 6-sets, I would estimate a sale price in the UK of somewhere near to £100 (US$130) for the set. You can get them fairly economically from Jackson's Art Supplies though:



Golden formulated QoR with a different binder to all other watercolours on the market. The conventional binders in most watercolours are usually gum arabic (from Vachellia seyal Delile (P.J.Hunter)) or gum senegal (from Acacia senegal L. (Willd.)). Gum arabic and gum senegal are both mostly composed of arabinogalactan, a gum polymer made up long chains that alternate between the pentose sugar arabinose and the hexose sugar galactose - so a bit like starch or glycogen, but they're both made up of the hexose sugar glucose. QoR watercolours use the binder Aquazol®, which is entirely synthetic.

Aquazols® (plural) are a range of polymers owned by Polymer Chemistry Innovations Inc. (PIC Inc.), which license the use of Aquazol® in watercolour to Golden. Instead of a mix of two sugars as the monomers of the polymer, Aquazols® use a single monomer - a derivative of the heterocycle 2-oxazoline, which is a 5-membered ring containing 3 carbons, an oxygen and a nitrogen. 2-ethyl-2-oxazoline (2E2O) is the monomer, so it has an ethyl group attached to the carbon in between the N and the O. On its own, 2E2O is a liquid at room temperature and boils at over 125° C (over 250° F or almost 400 K), where as the polymerised form is very different. Firstly, Aquazol® doesn't quite exist - it's a product family. The long chains of 2E2O molecules joined together aren't always the same length, so PIC Inc. separates the mixes into different average sizes and sells them under different names - e.g. Aquazol® 5 has a mean size of 5 kDa (kilodaltons, one Dalton is the atomic mass unit, the atomic mass of carbon-12 being 12 Da), Aquazol® 50, Aquazol® 200 and Aquazol® 500 are also sold, with mean masses of 50 kDa, 200 kDa and 500 kDa. Aquazols® are solid at room temperature and dissolve in water, making clear solutions, and this is why Golden promotes them as being "better" than gum arabic and gum senegal because those polymers are slightly yellow and thus slightly mask some pigments - specifically purples can in theory look slightly duller owing to neutralisation of the colour BUT in practice, I'm not convinced it's really an issue given how microspically thin the layer of polymer is over the pigments when painting watercolour! Aquazols® mostly find their uses for adhering metal gilt and for use as general adhesives in fine art restoration as they don't produce acid over time - and have been used this way for well over 10 years - long before Golden got hold of them.

Whilst I've not yet done a side-by-side road test for this, I have done a "first look" video of the QoR watercolours and swatched out this set:






1 comment:

  1. I'm glad you're back. I missed your posts and videos.

    ReplyDelete

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