Gamblin makes Portland Greys, literally inspired by the Portland skies when not ablaze.
The concept is that in making one's own greys the more white one ads, the more blue the greys get, or at least cool. So when working with values one tends to have temperature intrude.
I can't avail myself of the Gamblin at the moment, but was wondering what one could use to mix. Gamblin gives one all the component colours. Was wondering about some burnt sienna added.
If one is a Zorn user, then one knows that both the black and the white, are the blues.
Has anyone owned this problem yet?
Comments
I usually palette Paynes gray and Burnt umber as my cool and warm "darks".
Sit in a unlit room looking out at the landscape outdoors you be struck by how "gray" the natural world is at a distance. Light grays, dark grays, green grays and bluish grays. The sky, the fields and the distant trees are in very narrow bands of low chroma and varied hues.
Here is an email I received from Gamblin recently:
Thanks for contacting Gamblin.
A majority of our colors do not contain zinc oxide as a pigment. Below is a list of the few select colors which do use zinc.
Zinc White
Titanium Zinc White
Portland Grey Light
Portland Grey Medium
Portland Grey Deep
No other colors outside of that listing contain zinc in the paint formula.
Zinc White oil color has noteworthy limitations – principally, too much of it in a paint mixture makes for a brittle paint film. Also, Zinc White’s low tinting strength can contribute to yellowing if used liberally to create light tints or pastel colors.
Zinc oxide brittleness issues have been studied by Marion Mecklenburg and Charles Tumosa of the Smithsonian Center for Materials Research and Education. Mecklenburg was the first to warn that zinc oxide levels were getting too high in many brands of oil paint. Robert Gamblin visited Marion and Charlie in their lab at the Smithsonian in 2000 and discussed their research. Since then, we have followed their guideline to hold the zinc oxide content in mixture with other pigments to below 15%. For example, zinc levels in our Titanium Zinc White are well below this 15% guideline and our Titanium Zinc White has displayed excellent flexibility in repeated tests over time.
We think Mecklenburg and Tumosa’s research is incredibly valuable and hope that it helps painters make choices that result in more permanent art. The study states “It (zinc oxide) is especially problematic on stretched canvas primed with acrylic grounds…”. All paintings on stretched canvas are susceptible to movement and flexing. The inevitable flexing of a stretched canvas painting is further compromised using a high percentage of Zinc White. Even without Zinc White, the very strongest and most flexible oil paint film continues to oxidize for decades, becoming less flexible and more brittle over time.
Therefore we are strong advocates of painting on rigid supports. We also advocate that oil painting be done on Oil Ground rather than acrylic gesso. Acrylic gesso’s absorbent nature pulls oil binder away from fresh paint layers reducing flexibility. The non-absorbent quality of Oil Ground allows more binder to stay with the pigment for improved bonding and superior film strength.
For more information on these whites, please refer to our Studio Notes: https://www.gamblincolors.com/getting-the-white-right-by-robert-gamblin/
@TedB – There is some evidence that the zinc oxide used 100 years ago, most notably by the pre-Raphaelites, was different in particle size and processing technique than the modern zinc oxide. The problems with zinc oxide are documented on many different substrates, sizings, and grounds, not just acrylic.
BTW, the Vasari company in the US claims that they use in their zinc oxide oil paint a type of zinc oxide which is different than the other paint companies.
Regarding the Gamblin email response: notice that the zinc oxide research they follow to produce their zinc oxide containing paint is now over 20 years old, and currently is not followed by many manufacturers. MITRA advises against using any zinc oxide. I freaking loved the warm/cool neutrality and covering ability of Permalba white, but gave it up because of the zinc oxide, even though the alkyd in the paint would have helped prevent the delamination and cracking. I wrestled with this decision for a few years: even though I knew and accepted the findings about the zinc oxide problems, I didn’t want to change my practice because it was convenient
and so kept looking for reasons to continue
using it.
I suspect that the delamination and cracking associated with zinc oxide has several contributing factors, including unsupported canvas. But, I am prejudiced against using canvas at all.
I use acrylic ground to help block any contact of the oil with the substrate. I usually put on a lead white oil ground after the acrylic.
Atmospheric Perspective drains the chroma faster than it evens-out the value.