Colours Can't Believe my Eyes

For the next few world inspired landscapes the designs call for rolling hills that fade into atmospheric blue. Getting the colour correct on this kind of effect is tough, most artists know that mountains become blue towards the distant horizon and can replicate it with blue paint, for example a Sutton painting from last year. But it has never looked quite right to my eye when I painted those kinds of rolling hills. In the test paintings above (Back of No. 2996 Urban Jungle), the mountains dotted with shrubs look smokey or foggy but not atmospheric blue. In the Sutton painting I linked, the colours look a little too artificial. To resolve the issue I downloaded a beautiful photo from publicdomainpictures.net taken by Linnaea Mallette in Yosemite National Park USA which you see here....

Clearly, the mountains in the distant background have a blue-grey tint, while the rocks and shrubs in the foreground appear to be warmer colours like beige, orange and green. But what about the mountain in the middle ground, the one that appears in center of the photo? To my eye, it appears to be a dark green, with little patches of earthy violet or red rocks, at least, that would be how I would paint it... neutralized viridian and the new iron oxide violet perhaps. But a close inspection reveals a few surprises...

Above is a close up of the central mountain. I am still seeing green pine trees and purple-brownish rocks, albeit with a grey or blue haze. The caption of the photo said 'purple mountains'.

This is even closer, zoomed in, I hovered the mouse over one of the 'green' pine trees in the crop, and the colour picker showed that it was in fact, blue. The colour was a desaturated greyish blue, but still a true blue, not a trace of green or purple.

 

Next I checked what colour the 'earthy/rocky' area was using the colour picker, and it was also blue. The shade of blue was slightly different, it was blue-violet. You can see in the little box in the middle, it looks to be lilac. I looked all over not a trace of brown or green to be found.

My initial instinct was to paint this type of scene with neutralized green and red/brown paint or perhaps some purple, but that would be wrong. At the beginning of the blog, in the painting margins I tested out the idea that blue can in fact look like different colours if it was painted with some desaturation which I created with dilute carbon black, and hints of magenta or phthalo to tip the hue. Indeed, the colours I made looked quite different, but the colour picker analysis showed that they were all very similar shades of blue.

 So what is going on? I read over Handprint.com (MacEvoy) and he said that the visual system is capable of 'removing tints' to figure an object's true colour. For example if you walk into a room illuminated with green coloured light bulb, and the walls are a pale shade of green, your visual system will conclude that the walls are probably white. But if you walk into a room with a white light, where the walls are physically painted green, the visual system figures out that the walls are actually green. In the case of atmospheric blues, like in the mountain, the visual system effectively removes the blue tint and concludes that the pine trees are dark green and the rocks are a purplish brown. Look back at the photo! Those hills have green pine trees and brownish rocks.

Could there be another factor? When playing with the colour picker, I noticed that desaturated (greyed) versions of blue actually have a different appearance. Below, a closer look at blue violet: 

If you look at the left box, towards the top right , it is a purplish blue, whereas in the middle it has a distinct magenta (pinkish appearance). Here is a crop out, so you can compare the saturated to the desaturated: 

And the other shade of 'true blue' here is the saturated compared to desaturated:

 

The top is like sky blue, the square below looks like a dark turquoise, but they are actually the same hue. 

The take home message is that when blue becomes desaturated (more grey) it starts to look like a different colour even though the hue has not shifted. So in the mountain scene, the best choice for painting would be to use a true blue like cobalt (PB28) or phthalo sapphire (PB15:0) with a touch of diluted carbon black (PBk6), while the rocky area is blue violet probably isoindo blue (PB60) and a touch of magenta (PR122/PV19) with dilute carbon black. It sounds totally wrong, but I will have to try it next time I see rolling mountains in the distance. Another hiking trip to mount Sutton perhaps?

 And what about the green? Surely the beautiful rolling hills of Yosemite have abundant shades of green. Here is a colour pick on one of the shrubs in the foreground: 

The 'bright green' shrub... actually dark yellow, not even close to being green. after a bit of searching the pixels, I finally did find a tree that was chartreuse green. It is hard to believe my eyes, but almost the entirety of this scene is only 3 colours, blue (all the mountains), yellow (the shrubs), and orange (the rocks and brown appearing shrubs).