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DMSS
01-18-2015, 10:37 PM
I am working on an abstract acrylic painting. I have a shape that I painted with a tint of Ultramarine Blue (PB29) and Titanium White. Then I dry brushed/scumbled just a little yellow and a little white. The shape is mostly a clear blue sky color, and is not intense, so it is a very light Ultramarine Blue. I was thinking of painting a "shadow" in part of the shape, so in other words I want a darker color there, to look kind of like a shadow cast on it. I tried glazes with orange, red and violet, and none of these seemed right, so I wiped each one off. Any suggestions on how to approach making this darker? Would I just mix some more of the tint, only add a bit of black or grey to darken it? Would I paint that mix opaquely? Is there a glaze I could apply on top? Many thanks. I feel that this is a dumb question, but I can't seem to figure it out.

DMSS
01-18-2015, 10:41 PM
Maybe this, from Gigalot, posted in the Color Charts thread, would be a way to go:

"For me, it is better to take a close color from earth colour collection and to add white or black to correct value. After that a tiny amount of bright color can push your mixture to a proper way."

So, maybe I would start with black, add white to get a grey of the correct value, and then add the Ultramarine blue. I'll try it and report back, but I'd love to read any other suggestions you may have.

DMSS
01-19-2015, 12:02 AM
So, maybe I would start with black, add white to get a grey of the correct value, and then add the Ultramarine blue. I'll try it and report back, but I'd love to read any other suggestions you may have.

This worked reasonably well, painted opaquely. Is there a glazing solution?

Patrick1
01-21-2015, 10:06 AM
It would be best to post the color/area of the painting you have in mind. But generally (absent any other secondary, influencing light sources like skylight or other reflected light) the shadow will be a darker (but likely not greyer!) version of the main color.

Adding some black might get you close the right color. Or a darker version of the main color. So maybe a bit of a pure blue. If it's too saturated, you can grey it down a bit first. Getting the right shadow color is often trial & error, and sometimes you can't tell if it's right until some of the other colors are in place to compare everything together, and then it's 'bingo!'. Yes...you can glaze rather than paint more opaquely. Again it will be trial & error to find the right color - whether some complementary/near complementary, or a darker version of the main color.

P.S. I've seen abstract paintings with faux shadows painted on (as if the flat color area or color streak is partially eclipsed) and when done well, it looks awesome.

DMSS
01-21-2015, 11:23 AM
Thanks, Patrick. I don't have a photo, and for reasons not related to the shadow, I actually painted over the entire painting in black and white, and will start afresh with layers of color, and thus again tackle the shadow. When using a glaze to darken a color, as in to create a shadow, do you glaze the same color that, if you were painting opaquely, you would have added to the mix? In other words, let's say you have painted a layer of Pthalo Blue (GS) mixed with Titanium White, so you have a light cyan. And let's say if you were mixing to paint opaquely, you decided that you were going to add to the Pthalo Blue (GS) plus Titanium White mix some Ultramarine Blue and a tiny bit of Mars Black. If you wanted to glaze instead of painting the second layer opaquely, would you just glaze a mixture of the Ultramarine Blue and Mars Black? Or, are other adjustments required? Thanks for your thoughts.

I have not been able to find books or online resources that get into how to use glazing to mix colors. I am intrigued to try, but my experiments have not proven satisfactory and I feel like I am deep into randomness. I know Michael Wilcox has a new book called "Glazing," but it is too expensive for me, and I have not yet been able to find it on interlibrary loan. So, if anyone knows of another book or online resource on this I'd be interested.

Patrick1
01-22-2015, 05:30 AM
When using a glaze to darken a color, as in to create a shadow, do you glaze the same color that, if you were painting opaquely, you would have added to the mix?
David, that's a good question. I guess the only way to know for sure would be side-by-side comparison to see the difference between the 2 methods of darkening. I suspect there often would be some differences, but how much I don't know. It would surely depend on the pigments used. In your case with the blues, I will hazard a guess that there won't be much difference. Blues mix with much less surprises than 'warm' colors.

Off on a bit of a tangent: If I'm not mistaken, white thinly scumbled or glazed over black makes a blueish grey - even bluer than by regular intermixing. But black pigment thinly scumbled or glazed over white gives a much more neutral grey. An opaque yellow thinly applied over a very dark color will give a greenish color. Just some things I've noticed that traditional color theory can't explain.

DMSS
01-22-2015, 08:05 AM
Thanks, Patrick.

davidbriggs
01-26-2015, 08:53 PM
David, it's best to be clear about the colour relationship required first, and then to consider how to create that relationship in paint.

Absent any secondary influence such as differently coloured light sources, the shadow should be darker and greyer (lower in chroma) in proportion to how much darker it is. In other words, as the colours get darker, the chroma decreases, but the saturation (in the sense of chroma relative to value) stays the same. On such a series of such colours, which on my site I call a shading series, the effective balance of wavelengths (or chromaticity) stays the same and only the brightness changes.
http://www.huevaluechroma.com/101.php


Superficially we might expect to create such a series by mixing with black or glazing with a perfectly transparent black pigment, but actual black pigments tend to reduce the chroma too quickly relative to value - hence their reputation for muddying colours. You can correct for this by adding some more of the colourant pigment (ultramarine in this case) and for some colours you will also need to correct for any hue shift that occurs.

DMSS
01-26-2015, 09:11 PM
Thank you, David. That makes sense. My experience (limited as it is as at 2 years into my painting hobby I am still learning a lot) is that a tiny bit of black or grey helps darken colors, but that I have to be careful not to add too much, and I have been adding back some colorant pigment after reading about that on your site. In theory, I don't see a difference between (a) adding just a tiny amount of black at a time, and (b) adding more than just a tiny amount and then adding some of the colorant. To me it seems that in theory it all comes down to the ratio of black to colorant. But in practice I do end up adding back some of the colorant.

Just curious, do you know of a good book, website or article on the color mixing aspects of glazing?

davidbriggs
01-26-2015, 10:35 PM
In theory, I don't see a difference between (a) adding just a tiny amount of black at a time, and (b) adding more than just a tiny amount and then adding some of the colorant.

Just to be clear, by the colourant I mean the pigment that is the colouring agent, without white added. So if you are shading a mixture of ultramarine and white, if adding black makes the mixture too low in chroma (which it may not, by the way, since the tendency is less noticeable in shading blues), then you can boost the chroma to the extent needed by adding some pure ultramarine. Of course, if you instead added some of your original colour (ultramarine and white) it would be the same as just adding less black to begin with! The idea is that in the darker colours you in practice need a higher ratio of colourant to black to reach the same saturation.

Can't think of a good book, but you could discover a lot by making up a little swatchbook of graduated glazes of various transparent paints over paint strips of various colours.