No category of paint of whatever brand in the European Community is quite what it was prior to 2007. Every manufacturer has to contend with the European Decopaint Directive 2004/42/EC which limits the total volume of Volatile Organic Compounds ('VOCs'
in paints, varnishes and vehicle refinishing products in order to reduce VOC emissions and to reduce the generation of ozone in the lower atmosphere.
Any paint, varnish or vehicle re-finishing product must not exceed the maximum VOC level for that particular class of product and must carry a label stating the grammes/Litre of VOCs for that product in its ready to use condition. For decorative paints and varnishes ANNEX 2A sets out two limits of values, the first of which applied from 1 Jan 2007 – the second, and stricter limits, applied from 1 Jan 2010. For vehicle re-finishing products, Annex 2B sets out the limits applicable since 2007.
Manufacturers of paints have received torrents of complaints about household decorative paints, in particular white paint (80% of household paint used), turning yellow. They try to turn the VOC limits into a marketing advantage by referring to their products as 'low odour'. Many varnishes and gloss paints these days are water based and boast 'Low VOCs' but as anyone who has used water based varnishes will attest, the finish they produce is dreadful as compared to oil based ones. Neither does it adhere well – you can scratch it off with a fingernail.
I don't know the present situation with Hammerite and VOCs but I'd suspect that any change in formula is to comply with the Decopaint Directive. Hammerite used to be Finnigans, which was owned by Hunting Petroleum Services Ltd, but yes, it's now Akzo-Nobel. I have a tin in front of me – no idea how old, but the label says 'High VOCs – VOC content 25 – 50%. I don't think that label complies with the current directive which requires the label to state what the Directive Limit is for that class of paint, and what the actual is in g/L. I won't mention the (well known) brand of water based varnish I have which is destined to be binned, but it's rubbish and states 'low VOC 0.3%'. I also have Sadolin Extra Durable Woodstain, which is excellent and states: 'EU limit for this product is 400g/L 2010. This product contains 399 g/L, so it seems clear to me that in the interests of producing an excellent product, the makers have taken the VOVs to the limit.
Sorry it's so long-winded, but I hope it's of interest and relevance. Whatever paint you're using, if you're not happy with the finish the VOC limit might be the culprit. Personally, any paint that states 'low VOCs' stays on the shop shelf.
Same situation with rubbish water based 'decorative' (rather then 'preservative'
finishes for sheds and fences these days. Makers still try but fail to convince us that they're as effective as creosote, (banned for domestic use by the EU some years ago).