Utrecht answers questions about 30 year old artist oil paints

After finding the oil paints described in my last blog post I fired off a few questions to the experts at Utrecht Art Supplies. Matthew, one of the "Ask the Experts" representatives, said I was welcome to post his reply when I asked about sharing the info via my blog. Thanks Matthew! Here's his reply that includes some interesting details about their reformulating of Burnt Sienna. The colors I asked about are Cad Red Med., Cad Yellow Deep, Cad Yellow Light, Cobalt Blue, Ultramarine Blue Light, Burnt Umber, Burnt Sienna, Raw Sienna, Yellow Ochre, Alizarin Crimson, and Viridian. The few taller caps that wouldn't easily release gave up their grip after a day or two soaking in turpentine. -pw

MY QUESTIONS TO UTRECHT:

"I've discovered a dozen oils I likely bought 1979-1982 at the Boston store and misplaced. The couple I opened looked nice. None of the tubes are unusually stiff. The Titanium white oozed oil. Some have taller caps and the tube tops looks dull and might read Utrecht Linen Inc. Maybe a different metal?

Is there any reason these paints shouldn't be used for serious work.

If usable would you suggest I retube them?

Were colors at that time as archival as today?

Would you expect the colors to be reasonably close to a new tube?"

UTRECHT'S REPLY:

"Linseed oil is at its peak adhesive power when fresh, but it can have a very long shelf life. While it's possible the vehicle may have diminished somewhat in quality (impossible to say how much), if the paint appears to have the normal consistency and even sheds excess oil, it's probably fine to use.

We have always used top quality pure pigments, and while global sources have changed in some cases, the colors will be dense, potent and lightfast (permanent pigments don't lose lightfastness in the tube). The biggest difference will be with Burnt Sienna; terrestrial sources for certain earth colors are becoming played out, and in the case of Burnt Sienna years ago we began to see unacceptable variation in color from batch to batch. Rather than offer an inconsistent product, we reformulated to use a synthetic red iron oxide to  offer similar mixing properties with much more reliable color. The new product has a darker mass-tone appearance, higher tint strength and greater transparency. I think the rest should be similar to new paint.

The tube is aluminum, but it's probably oxidized and looks dull. I don't think there's any reason to re-tube based on appearance; the interior of the tube should have been unaffected. Stretching the limits of memory, I believe we used uncoated tubes for oils and coated for acrylics at this point in time, but regardless, if the paint did not oxidize, I think there's practically no chance the interior tube surface was affected.

I hope this helps; thanks for your question!"

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