Hue Shift on Tint

I’d like to build on what I’ve written in the previous blog posts about mixing colors more efficiently by identifying the hue of the intended color and then using an understanding of hue shift on neutralization of colors to trace the nearest tube color that can be used to match. There is a two-fold intent here:

  1. To establish a more systematic approach to understanding hue shift.
    • Is it true that neutralizing colors always shifts the hue towards the relatively cooler side of the color wheel? For example, neutralize yellow, and it looks greenish, not orangy.
  2. To provide an efficient color mixing process that artists can use to expedite painting, and spend less time mixing.
    • Painting time is precious, and unless the goal is just to mix colors, most artists will prefer to mix and lay down usable color quickly. Think here of the paintings of Sorolla or Sargent. Their color ‘matching’ may not be photographic or hyper-realist, but it is appealing and so effective that we consider them ideal. The way they were painted is the way they should have been painted. Too many of us get stuck on color matching and miss the dynamic action-response nature of painting that is a distinguishing characteristic of the medium. A robot can be programmed to observe, mix color and ‘print’ with paint according to the Munsell color system.

Here’s the ‘hue-shift’ hypothesis:

When a given color is mixed with a neutral grey of any value, the hue will shift towards the cooler neighboring color on the color wheel.

How do we test this hypothesis?

Plotting with computer scans

The simple way is to take a range of tube colors and tint/shade them to pre-determined values, and then read the colors of each with a digital color reader or scanner. The computer’s HSL reading will provide Hue numbers for each, and these can be plotted to show the hue shift. One person can do this, and I encourage readers to attempt it. All you need is patience, colors, white boards for the colors and a scanner. You can get the HSL values via the color picker. The end results might be plotted on a spreadsheet that, for each tube color, has the Value number (how light or dark it is) as rows, and the Hue number as columns. The Saturation number can be input into the cells for the colors measured. This will give the hue-shift profile for each tube color. Depending on how many values are recorded, we can potentially see a vector or curve of the hue-shift for that specific tube color.

One person can do this, and I encourage readers to attempt it. All you need is patience, colors, white boards for the colors and a scanner. You can get the HSL values via the color picker. The end results might be plotted on a spreadsheet that, for each tube color, has the Value number (how light or dark it is) as rows, and the Hue number as columns. The Saturation number can be input into the cells for the colors measured. This will give the hue-shift profile for each tube color. Depending on how many values are recorded, we can potentially see a vector or curve of the hue-shift for that specific tube color.

The end results might be plotted on a spreadsheet that, for each tube color, has the Value number (how light or dark it is) as rows, and the Hue number as columns. The Saturation number can be input into the cells for the colors measured. This will give the hue-shift profile for each tube color. Depending on how many values are recorded, we can potentially see a vector or curve of the hue-shift for that specific tube color. (In a future post I’ll submit an example chart.)

Note that while the same color swatches may scan differently in different scanners, as long as all the results are done with the same scanner we should get a reasonably accurate set of results. Monitor calibration does not factor in because we’re using the computer’s color picker to determine the HSL number for each. Note that due to pixelation, for any given swatch a few measures should be taken and the mean selected.

However, ‘objective’ computer color is not the same as perceived color. So here’s a subjective approach.

Plotting with user color matching

  • Preparation 
    • Take a set of tube colors that align with the primaries and secondaries on the color wheel.
    • For each, neutralize so that there is a light, medium and dark version. To avoid extreme desaturation, we don’t want to mix very light or very dark versions. On a scale of 1-10, perhaps a 7, 5 and 3 would suffice (but this can be modified during the experiment).
    • Put each of these individual colors on a color swatch, numbering them on the back with random numbers that are indexed to the tube colors on a chart the test users don’t have access to (so they can’t look at the numbers and correlate which swatches came from which tube color).
    • Set up a wall chart with the color spectrum in a horizontal grid, with chromatic hues in the middle, and lighter versions of the same hue above them, and darker versions below. Note that for each column the tints and shades of the same hue as the core chromatic color. These will have to be verified with a digital color reader to ensure that hue-shift isn’t skewing the chart itself.
    • Index each color on the chart with a number – it could be the Munsell number or something else that is easy to reference.
  • Validation
    • One at a time, give each user a set of colors across the spectrum (the count should be determined by how long the user can provide focused matching).
      • To get a good sample, ensure that in the end, all the swatches have been given at least three times to users.
    • Have the users match each of their swatches to a cell on the wall chart, and note the number of the cell matched.
    • Plot all user selections on a spreadsheet (see above) to determine hue shift for each tube color.

It would be interesting to have multiple instances of both types of experiments using a broad range of tube colors, and to bring the results together into a public knowledge base. The end result would be information of hue-shift for tube colors that artists can then use to mix colors faster. It can also help us rank tube colors in terms of how broad their hue mixing potentials are. How exactly would this work? Here’s a scenario.

Practical Application

  1. When starting a painting, the painter selects tube colors they want to use.
    • The artist might have preferred colors, or alternatively
    • A more sophisticated (future) color recognition software can propose tube colors based on the color profile of the image.
  2. The artist becomes familiar with the hue shift of each tube color.
  3. To match color:
    • For the beginner, the artist uses a Munsell color swatch to identify the target color, then uses the hue-shift chart to identify the tube color that will produce the closest match.
    • The advanced artist makes a mental note of the desired color, and from knowledge of the hue-shift charts for her palette, picks the corresponding tube color.


In publishing my Hue-shift based methodology for color matching, I’m ‘open-sourcing’ the idea so that the community can pick up on it and perhaps together we can be systematic about collecting this data. Software engineers may someday pick on this and create color-detection to tube color technology to expedite the process for the painter. Imagine you’re out in the field painting en Plein Air and you’re having trouble determining how to mix a color. Having the Zuniga hue-shift charts on hand can help. Alternatively, imagine a phone application lets you take a picture, zoom and select the problematic spot. Since you input the tube colors in your kit, it will tell you which color is the fastest path to obtaining the desired hue at the desired value.

— Roy Zuniga
Langley, WA


Copyright (c) 2017 Roy Zuniga

Neutralizing Colors Efficiently

I keep hearing art instructors tell students to neutralize saturated tube colors with their compliments. To neutralize Red, use the ‘compliment’ Green, for Orange use Blue, and Purple will tint Yellow. There are problems with this approach:

  • True compliments that neutralize colors are not what is popularly asserted. As I’ve written elsewhere (see Software Color Doesn’t Agree), what really neutralizes a red is not green, but a teal. Orange is neutralized somewhat greenish blue, and yellow by a somewhat purplish blue, as this chart illustrates (number correspond to hue numbers in the HSL computer color space):


  • One of the reasons why the conventional advice evolved is that to the naked eye, it looks like the traditional compliments do neutralize. Take a Cadmium Red and mix it with Viridian and it will look neutral. So there is some truth to it, but it’s not a perfect neutralization. Keep this mind:
    • The blended color is not really a true compliment. It might not even be the hue of its label; it’s a tint of a warmer hue. The color you’re mixing with is not a tint of the hue you’re thinking of. That’s because hues shift towards perceptually cooler temperature as they are tinted. Therefore, a dark green like Viridian would look warmer if fully saturated and brighter.
    • Tinting with the ‘compliment’ means that a certain value (aka brightness) inherent in the added color is forced on the mixture, and it’s likely not the value you’re targeting. It’s very hard to mix traditional compliments for lighter value ranges, for example. If you want to neutralize a pink, you have to find a really light green. In practice ­one ends up mixing in white, and at that level of tinting, you can’t really discern the true hue anyway. So as long as it is close to the cool or warm we’re looking for, we’re satisfied.
    • Phenomena in perceived colors are projected into the color mixing process, and this doesn’t help. It’s true that with a cool light, the highlights will obviously be cool, and the shadows will look warm. We tend to think the light hitting the shadows is of a complimentary hue to the one hitting the lights, especially as the light is saturated. We get this phenomena in the extreme with sunsets – the very warm yellow setting sun will light up warm clouds where it hits, and the very same cloud will look blueish grey where the light does not hit. The color of the form is the same on the light and dark sides, but the complimentary highlight/shadow phenomena of light makes them look very different. Just because that’s how color is perceived doesn’t mean that’s how it has to be mixed!

Despite these tendencies, professional artists will arrive at good results, not because they are literally following the traditional compliments theory. Rather, through experience and a lot of mixing, they get what they want, and chalk up any deviations to the inherent ambiguity of artists’ tube colors. One manufacturer’s Brown Pink is a lot more orange than another’s. Not everyone can tell the temperature difference between a maroon and a scarlet.

In fact, we would benefit from an objective hue numbering standard for hue colors. For example, regardless of the traditional name, an additional hue number would be printed on the tube, along with some saturation and brightness rating. This could be mapped to a computer model, like Hue Saturation and Brightness (HSL). But that’s a topic for another day.

So how can we more efficiently mix the greys we’re after? The answer is actually straight forward, but it requires throwing out another rule that many painters who ‘tint with compliments’ swear by (including the Impressionists): don’t use black because it ‘muddies’ colors. Let’s now also dispel this scare tactic – a ‘muddy’ color is just another grey that finds itself in the wrong place. Any grey can be a muddy color in a given context. If you’re painting a sepia portrait, warm greys are wonderful. If you’re painting portrait in a cool light, the same grey will look muddy.

It’s ironic that artists who loathe black use white quite liberally. While both black and white are neutral colors and technically both have the capability of ‘muddying’ colors, artists don’t dump on white because at the lighter range, we’re much more forgiving of ‘wrong’ greys. We actually don’t see ‘muddy’ whites. Let’s call a spade a spade: all tints are greys, and ‘muddy’ colors are simply greys out of context.

So the problem is not about having black on your palette; the problem is with not understanding how to properly tint colors. This brings us back to two areas we touched on: hue shift, and target brightness. Hue shift is simply the phenomena that colors will look cooler when tinted. Take Vasari Ruby Red, for example, mix it with various shades of grey, and it will look pink in the lights and lavender in the darks (as shown here).


Take a lemon yellow, mix it with black, and you’ll be convinced that there is a warm green in the mixture (but there isn’t).


It’s valuable to know the expressive range of your colors on their own, and how they change with pure greys. This will simplify the thought process and let you focus on other challenges in the work. Develop a sense for that color’s hue shift on tinting. The best way to do this is to simply mix up a range of light and dark greys from black and white, and then mix your tube color into each. This will take some time, but if done on some canvass sheets, you can actually pin them to a cork board on your wall for reference. That way, instead of winging it every time guessing at the hue you’re looking at, you can instead compare it with your wall swatches and then pick the proper tube color and know which value of grey to mix it with.

What I’ve touched on here is a method of mixing that relies on using true greys – and this means use black! Let’s face it, if the traditional method of using compliments to neutralize is true, then exactly half way between the two colors is a perfectly neutral grey that is indistinguishable on its own from a mixture from black and white. As you know, black and white are cheaper than other pigment colors, so why waste all that money having a perfectly complimentary tube color for every color you intend to use? That’s anyway not possible because pigments don’t align neatly with the saturation and value of a given tube color’s perfect compliment. You’d also have to have many more colors that would otherwise be the case if you just mixed to grey. So take the mythology of compliments out of your mind for color mixing. Put that traditional color wheel in the bottom drawer. There is certainly a place for oscillating between warm and cool colors in a painting for interest. To achieve that level of visual excitement on the canvass, you can just mix each color directly, and apply it. Simulate the complimentary effect of light in the image, not in the mixing process. You’ll preserve visual interest while conserving on precious colors, and mix faster once you know your colors native potential.

Copyright © 2015 Roy Zuniga

Tinting with color recursion

To mix a tint you have a couple of choices. You can sneak up on it (as described in the ‘Tinting the hard way’ topic discussed elsewhere), or; you can identify the tube color based on the hue in the Tint-to-hue chart, or; you can mix colors that are 60 units apart on both sides of your target color. The last is color recursion, as illustrated here:


Here’s a circular view of the same phenomenon:


In this case, the intermediate hues aligned with the expected midway numbers between our primaries. The other interesting part is that the saturation went down by a half on all of them. This means that a blend between two saturated colors results in a saturation half-life. You can mix the product of the mixtures again and the results recurse back to the original hues, albeit with even lower saturation and value:


If this persisted with blends of the intermediates recursively, it should result in neutrals (close to zero saturation), as this recursive blend diagram shows:


Finally, taking the exercise even further, you can get a lot of interesting colors:


copyright (c) 2014 roy zuniga 

Turning form with color

Turning form so that it appears natural is perhaps one of the hardest things to do with color. Creating a value range by tinting a single color may result in an accurate light to dark rendering, but it will look like a colorized photograph, and not natural.

A rounded object, like a ball, will have a local color that changes in hue based on the temperature of the light. If the source light is warm, the shadow areas will tend to appear cooler. Even though the objective local color of the ball may not change, the perceived color does change due to hue shift on tint. As the form turns, the light hitting it changes in color also, further impacting the hue shift in perceived color.  Thus it will not suffice to have a blend of one single hue to several light and dark greys because most certainly the light colors will need a color hue that is different from the shadow areas. Thus we need progressions from light to dark that also shift hue along the way. To master form, you have to mix color progressions that are true to the perceived hue shifts.

Let’s use the apple on my desk as an example. I photographed it an used a graphics program to inspect the pixel colors.

The first column (A) shows the hue-saturation-brightness (HSB) color values as detected on the photograph. Note the variety in hues, from #44 through #51, all of which describe a ‘yellow-green’ apple. That’s a lot of colors to mix, and a typical beginner approach is to replicate each one individually.

ImageThe second (B) shows a ‘colorized’ simplistic approach to mixing the apple colors, i.e. simply taking the lightest and darkest and blending them in steps. While this is expedient and the diligent artist can of course produce a realistic looking apple if the values are carefully observed. Remember, if the values are correct, the image will be impressive even if the color variety isn’t as rich as in nature.

The third column (C) represents a more differentiated approach that both avoids having to mix every variation perceived, yet at the same time provides accurate tonal value range for a realistic rendering without sacrificing naturalistic color variety. The artist identifies a few key colors in the progression that represent HSB ‘way points’:

21 – The brightest color next to the highlight. Remember that the highlight itself is an almost a pure reflection of the light source and won’t have any local color. So it’s best to start next to the highlight.

24 – A close approximation of the local color before the form turns into the shadow area. The other colors, 22 and 23, can be blended on the fly by mixing 21 and 24.

27 – The color of the core shadow. This is where the form turn away from the viewer toward the shadow areas and is typically the darkest area on the main surfaces of the object itself. (The pit of the shadow area will often be darker.)

30 – Color of the reflected light. In this case, it is the warmer light is reflecting onto the right side of the apple. There is also a cool reflected light on the opposite side.

The final progression is for the shadow areas. There was another cooler daylight light source that hit the shadow areas. Two boundary colors were established for this progression, 31 and 34. The intermediate colors 32 and 33 can be mixed on the fly as needed.

Thus to render this apple, the artist would pre-mix four colors in the primary progression, and two in the secondary shadow area. Some economy of mixing can be achieved by using the local color (24) and diminishing the saturation and brightness a bit to get the warm reflected light color (30). In other words, mix five colors (three for the warmer progression and two for the shadow area, and then mix the warm reflected light color as a variant of the midtone color).

Warm-cool color oscillation can add interest in the shadow areas. This can be achieved simply by putting some cool reflected light color (34) in the area of the warm (30), and visa versa. Care has to be taken not to overdo it and thereby loose the differentiation between cool and warm areas of the shadows. A similar approach can be taken on the lighter areas by creating cooler variants at the end and strategically mixing them in. All the variations, however, should not interfere with the systematic approach that will allow you to put down the illusion of unified form that has naturalistic color. Anomalies can then be added opportunistically for interest. This is how masters astonish us with both speed of execution and naturalism of form. This approach is the opposite of the tendency artists have as keen observers to major on the variations, which only results in a noisy and fragmented visual experience.


copyright © 2014 roy zuniga 

A Tint-to-hue reference chart

To find the tint or shade you’re looking for, use a chart like the one below (available here in detail for download). Identify the tint in one of the middle colors, and then see to which saturated hue it corresponds by tracing to the color on the closest edge.


This spectrum of blends is to provide a greater range of tints of the colors as they get blended with lighter or darker greys. Why is this important? For one, tinting actually causes a perceptual shift in hue. Even though a color sample in the computer will prove that the hue hasn’t changed, to the human eye, it seems that way. Lighter tints gravitate towards their neighbor, sometimes warmer (a red tinted lighter tends to look more like magenta, while a yellow tinted tends to look greenish, with the darker colors seeming a bit warner). This is exactly why we can’t rely on identifying the hue first in our minds. In the case of tints, the physical color will invariable be something else, albeit close by in hue.

The next challenge is of course mapping a given saturated color on the chart to the tube colors in your studio. We’ll address this mapping in later topics. For now, please use your best judgment visually mapping the chart colors to the closest tube color for mixing.


copyright (c) 2014 roy zuniga

The simple Tint-to-hue method

Here are the three steps to quickly mixing your color:

  1. Look at your subject and generalize the color area you’re interested in. Arrive at a color in your mind that is a summary blend of the tonal area.
    In some ways, this is the hardest step. You have to train yourself you see color areas, not just distinct color points. This means that when you look at mid-tones in a cheek, you think of one color that is the foundation for that tonal range. It helps to squint. Here’s an example:


  1. Depending on how light or dark that color is, pick one of the tint charts. Locate the tint swatch that is the closest approximation, and trace to the hue at the top. It will have a number.
    For example, you’re looking at a flesh tone and decide that the closest color on the chart is a tint under the color 10 (a slightly warm red).
  1. Find the tube color for 10, and mix in a pure neutral of the right value (lightness).
  • Note that if the hue is of a darker value, the mixed neutral should compensate by being lighter.
  • An alternative to mixing in a neutral is to mix the direct compliment, which in this case is hue 190 (slightly blue-teal). For this to work, the compliment has to be of exactly the right value, however.

That’s it! With this simple process you can quickly zero in on your color. I call it ‘Tint-to-hue’ because you start by identifying the tint, and then look up the hue. This is much more efficient than the ‘hue-to-tint’ method described earlier. 

The devil is in the details, of course. It is one thing to look up a tint on a computer chart. It is quite another to be able to map that to mixtures of your tube colors. We’ll explore applying this theory to the studio experience next. 


Copyright (c) 2014 Roy Zuniga 

Tinting the hard way

Before we cover the more efficient Tint-to-Hue method, let me digress and talk about the hard way to do it: the Hue-to-Tint method. It goes something like this:

  1. Look at a subject and generalize the color area you’re interested in. Arrive at a color in your mind that is a summary blend of the tonal area.
  • Then decide which hue it is based on. (This is the crucial divergence from tint-to-hue, where you find the matching tint, instead of corresponding hue.)
  1. Go to that hue, and tint it to the appropriate value and saturation.

This also sounds simple. So what’s the problem? The problem is that hues actually shift on tint. For example, take a yellow and mix it with a neutral, and it will look greenish. Hue-shift is an interesting phenomena. A visual survey shows that invariably (except for blue), all hues shift towards the neighboring cooler color on tint. With this understanding in mind, let’s try those two hue-to-tint steps above, and see an actual mixing experience:

  1. Identify a color based on a target region in your subject. Let’s say it’s this color:
  2. To me the hue of the tint looks like rose/warm magenta.
  3. So I take magenta and neutralize it with white and a light version of its compliment (which in the traditional model is yellow-green). Here’s what I get with that mixture:
  4. De-constructing the steps: about midway in the magenta-to-white mixture I arrived at the right value (step 1), which was too intense. Adding the traditional compliment yellow-green (step 2) should have neutralized it (but notice there is no neutral in the magenta tint-to-yellow green blend steps). So in step 2 I end up with a color that is pretty darn close, but no quite what I want (the hue still isn’t right, it’s too yellow and under saturated). This is frustrating.
  5. Being the perfectionist that I am, I want to add other colors to nudge it to the right hue. But what to add? More magenta just puts it back into the place from where I just came. It looks like it could be a bit warmer, so maybe adding a tad bit of red will help:
  6. I mix up a red tint to arrive at the desired value (step 3), which I then mix with my step 2 color (if I still have enough of it and don’t have to remix it), and blend the two until I arrive at a color that is close enough to call it good (step 4). It’s not a hundred percent accurate, but close enough for artistic work. What is missing in color accuracy is made up with accuracy in value. It’s not 100% accurate, but it is believable.
    Notice that to get to this color, I had to go through four mixes (assuming I got them each right the first time, which doesn’t always happen).

This is the Hue-to-tint method. Trial and error exacerbated by a faulty compliments model (that injected too much yellow into the mix, for example). Can you arrive at the color you want eventually? Yes, of course. With enough time, paints and elbow grease, you can sneak up on your color from all kinds of directions. 


copyright (c) 2014 Roy Zuniga