Your question is badly phrased.

If you really want yellow with no green, then try illuminating your art with 589nm laser light.

Any yellow pigment will have green. Otherwise, it would be distinctly orange.

PY110, which might be your “Indian Yellow”, is named “Stil de Grain” by Talens Rembrandt.

Another possibility is “Hansa Yellow Deep” by Gamblin and others.

If a pigment had no green, then it would not appear as yellow unless it also had no red. That would require a very narrow color range, entirely within the yellow part of the spectrum. Due to the way that chemical substances (such as pigments) handle light, such a narrow band is very difficult to achieve. Remember that this refers to a widely-produced and affordable pigment, rather than an expensive laboratory specialty.

Presumably you asked the question because you want to mix the yellow with blue, and not get a green result. Not happening unless the “yellow” is actually orange, or the “blue” is actually purple.

Digital colors have different properties.

Yellow with no green would be very similar to a brick house with no bricks.:)

That which the human eye witnesses as “Yellow” is truly equal reflectances of both Red, and Green light. So, true Yellow is actually 50% Green light.

As someone has already mentioned, Yellow with no Green would be very akin to Orange, or even Red. However, a less Green Yellow might be something as Cadmium Yellow Medium, or Cadmium Yellow Deep, or even Indian Yellow, as someone has already mentioned. But, realize,…those are no longer Primary Yellow; they are offshoot colors of Yellow, and their hues would be located around the color wheel, some distance away from true, primary Yellow, heading toward Orange, or Red.

Now that the Champions League is over, I have time to answer in depth…

(A) If you have a real computer or tablet, you can do this digitally. A phone is too small. If you only have a phone, then use paint on paper:

Create a yellow blotch adjacent to a blue blotch, each maybe 4in square (since you spelled colorful rather than colourful, I assume you’re not using the metric system). The exact color does not matter.

Hold the blotches so that your left eye can only see the yellow and your right eye can only see the blue. Place a perpendicular barrier, if necessary. Now, do you see a green blotch? Almost certainly not! Instead, you see YellowBlue. That is, your brain does not blend the two colors.

If you happen to be colorblind yellow-blue, then you can try it with two other colors that you can distinguish.

(B) If you are interested in using yellow with blue sky, then my guess is that you want to do sunset effects.

Be aware that the yellows and reds of sunset are less chromatic than you might think. Due to the large dynamic range (values, light and dark), none of printed, painted, or ordinary computer images can capture the true lighting. Some of the colors must be rendered with intentional change in any or all of hue, chroma, and value. This choice is made by the artist (or software).

The most common choice made in printing or software is to use exaggerated chroma, to compensate for lack of dynamic range. This is because high chroma colors are generally perceived as being lighter than they really are. Also, magazines and post cards have been doing this for so long, that it is expected.

But in terms of artistry, exaggerated chroma is not the best thing to do. Careful management of light and dark areas, with moderate chroma, and the use of adjacent light/dark, is generally better. This is because a flashy, chromatic painting may look appealing when viewed once in isolation, but rapidly becomes intrusive and tiresome when permanently mounted on an interior wall.

(C) There is a tendency for artists to include a round sun. This is not necessary. It can be suggested by the glow of surrounding cloud, or blocked by terrestrial foreground.

Regardless of the size of canvas: If the diameter of the solar (or lunar) disk is a mere 1/4 inch, it will be at correct scale when viewed from 2 feet away. Of course, you the artist can do what you like. But newbies like to make a very large disc, which would only be appropriate for a telephoto effect (meaning, very little surrounding cloud or landscape appears).

(D) If you are working alla prima, you will find it hard to avoid green when working with yellow and blue. Obvious solution: Don’t do it alla prima.

You can paint the background blue sky, let it dry well, then add your colorful sky effects in front of it. For this, you need to define the clouds using opaque paint; probably Titanium White mixed with some appropriate color. However, that will product a pastel effect, which might not be what you want. In that case, let the opaque layer dry, then glaze over it using transparent colors.

Just beware of making the edges too sharp.

(E) Ultramarine is usually not the best choice for sky blue. It is too purplish. Phthalo Blue is much better. The slight lean towards green is usually desirable, if you control the chroma.

You can manage the chroma of Phthalo Blue with a mixing complement. The correct choice is not certain, because colors (especially earths) vary from manufacturer to manufacturer. Might be Raw or Burnt Umber, Burnt Sienna, or Venetian Red.

That thread about how to avoid green in the transition zone between blue and yellow parts of skies, is a good, important one. It’s a problem that was vexing me for years. As mentioned, usually the solution is to use a very low-chroma (greyed) transition zone. Sometimes even neutral grey. Pre-mixing it is easier than mixing it on the canvas. Adding a mixing complement (like red, magenta, or violet) to counteract unwanted greenness is another option. That premixed grey/near-grey might look wrong (too dull) on the palette, but on the canvas, in the context of the surrounding colors, it will look right if you got the value right. And Pinguino makes an important point, if you’re interested in realism: the ‘colorful’ colors in sunsets are often a lot less saturated than they appear, it’s their high brightness that makes them appear so.

But…sometimes there really is a small strip of actual green in the transition zone, but it’s so low-chroma it’s difficult to discern much, if any, green of it. Increasing saturation in Photoshop to maximum will clearly show it, if it is present. But the important thing is that they are usually light-valued and very low chroma…i.e. barely green.

If you have the latitude to choose your starting blues and yellows, choosing ones that don’t mix to green (or do so only minimally) is another option, as already mentioned. A violet-blue and a very orangy-yellow (or more likely an actual orange), will minimize unwanted greens. You might want to do mixing samples, tinted with white, to show the various midway colors between various blues and yellows, oranges, red-oranges. That way you don’t have to do mixing experiments in the middle of your painting. Some combinations will give pretty much a perfect neutral grey, if that’s what you want. Other near-greys will have various subtle hues to them…which will also be useful to know how they’re made.

Off on a tangent: yellow-orange or even a middle orange can be used in place of yellow (i.e. no actual yellow on the palette). This will intentionally skew your gamut to give a much warmer, earthier overall coloration to your scene…and not just for landscapes.

I recall Grant Fuller spoke about this a lot. From his Youtube channel: The swatch on the right is watercolour Cadmium Orange. He spoke about adding a touch of “yellow” to the Cad Or, though he didn’t say which one. He specifically mentioned about creating a combination in the sky that didn’t blend to green where the passages mingled. Just an example of a strategy. Blue is CoB toned down a little with the Cad Or. Dark, stormy sky is UB + BS.

These plots might help in visualizing the colour relationships recorded in the photo and what “increasing saturation” does to those recorded relationships.