Brilliant points and questions Suzanne. I remember that I experimented with quite a few colors when I got started painting (buying sets of colors like you mentioned in your post.) However, my palette quickly dwindled down to a simple dual-primary palette (named for its inclusion of two of each historic primary colors(red, yellow, blue)-(often warm/color variations)).
My current “reds” are Cadmium Red Light and Alizarin Crimson. I do sometimes add Cadmium Red (a.k.a. Cadmium Red Medium) if the reds that I require for a certain piece will place more weight on the Crimson—as it is a very thin paint and opacity is a significant concern in my earliest stages.
I don’t use Ochre at all so I cannot really comment on that particular color. Hopefully someone else here can chime in on that. 
Thank you for your response, and what is on your pallet is what’s on many. From a technical point of view, and my desire not to waste paint I’m wondering if these other remaining five colors might be technically the same thing as cadmium red light. Particularly scarlet red, permanent bright red and napthol red.
This is a complicated subject. There are actually a ton of reasons why people have colors on their palette—or leave them off. Often there are several factors at play in someone’s decision. Here are some possible reasons:
- Gamut
- Mixing profile
- Convenience color
- Drying profile
- Opacity/transparency
- Lightfastness
- Other archival concerns
- Toxicity
- A teacher said so
- Philosophy
These are not necessarily in any order. Also, there’s a lot of overlap between many of these. They could probably be reduced to a smaller set. But—I’ve heard all of these in one form or another from different painters.
Gamut is a fancy word that means the range of colors you’re able to mix. These days most people I run into go for a broad gamut that can mix most of the colors they run into. Others keep a more limited base palette and add extra colors depending on what they’re painting that day.
Mixing profile is a term I just made up. It refers to the way that color mixes with other colors. Each particular pigment is unique in this regard. In fact, two tubes of paint might look exactly the same to your eye but mix with another color differently. Most people I know are not aware of this fact, but through experience have developed a feel for how that color mixes. They might try a similar color but conclude that it “doesn’t mix right”. Also, some people might prize one pigment because of its subtle influence on other colors, while others might prize another pigment’s intense colors. Still other people might feel a color makes everything “muddy”, or that another “takes over mixtures”. These are all related to mixing profile.
Convenience colors are very much related to mixing profile. Basically, it’s just a color that might technically be unnecessary on their palette, but that they use frequently as is, or it mixes quickly to other colors they use frequently.
Drying profile is another term I just made up. Some pigments dry more quickly than others. Also, some pigments dry matte and others dry glossy. Depending on how you work, either of those can be good or bad. A common example of this is people who don’t keep Raw Umber on their palette because of it “sinks in”. This really just means that it tends to dry matte. It’s also worth noting that adding medium can affect whether pigments dry matte/glossy/fast/slow.
Some people prefer a given color because it’s opaque, transparent, or translucent. This can be related to both drying profile and mixing profile (transparent colors mix differently than opaque). It can also influence certain techniques. For example, glazing generally requires transparent pigments. Other techniques depend on being able to cover things up and prefer opaque colors.
Lightfastness plays a big role in some people’s selections. Some pigments are well-studied and known to be problematic or perform well. Others are newer and less well-studied—particularly newer pigments like Quinacridone, Napthol, and even Cadmiums.
There are also other archival concerns, like tendency to crack or yellow. Not everything here is conclusive. For example, Zinc White is known to create a brittle film and is prone to cracking and chipping. However, it’s not completely settled if mixtures with zinc and other white pigments have the same problem.
Of course, toxicity is a big concern for some people. Even here there’s some debate about what’s toxic and what’s not. There are some pigments like lead and cadmium that are definitely toxic, but newer pigments are less well studied.
A lot of people probably start off with certain pigments because their teacher (or some other authority) said so. This is a great way to start off since you can get the benefit of other’s experience without having to understand all the subtleties. Over time you might change based on your experience or influence from other teachers.
Last but not least is a given painter’s philosophy or beliefs. This can be related to many of the other things on this list. It can also cross a line into dogma. Some examples of this is a preference for the highest chroma colors to instill more “energy” into a painting, a belief that black doesn’t exist in nature, or a belief that certain colors have some psychological effect.
So, for a given pigment is often a complex combination of several of the factors listed above. Take Cadmium Red Light, as you asked about. I know several painters who will never put it on their palette because they avoid toxic cadmiums. I know others who use it simply because their teacher said it was good. Others like the fact that it’s one of the highest chroma red pigments available. There are similarly bright red pigments whose lightfastness isn’t well understood. Some feel that Cadmium Red Medium is too close to other pigments on their palette (e.g. Alizarin), and Cadmium Red Light is slightly further away—which creates a larger range of mixable colors. Others I know prize its opacity. Others don’t use it because it’s too opaque.
In the end, I recommend experimenting with different pigments to see what works for you. It’s also important to learn more about all the different factors above, and which of those are important to you personally. Ultimately there’s no right answer here—you just need to get hands-on experience with how that particular tube of color mixes with all the other ones on your palette, and learn how that color lines up with your priorities in terms of drying, transparency, toxicity, lightfastness, etc.
One in particular item I’ll point out is mixing profile. This one is worth calling out because many people aren’t aware of the fact that mixing profile changes based on the pigments involved. To reiterate, 2 tubes of paint might look exactly the same to your eye, but mix differently because the pigments are different. The oil and additives in a particular brand can make a difference as well. Some Napthols can look close to Cadmiums out of the tube but will mix very differently. They’ll both make orange if added to a high chroma yellow, but you might need more of the Napthol to get to the same orange. The resulting orange might be a different chroma or value. IIRC Napthol Red is more transparent than Cadmium Red, which might be a benefit or a problem. Again, there’s no right answer here—it just depends on what you want and need out of red on your palette.
I can’t speak much to scarlet red or permanent bright red because those are manufacturer’s names for a certain pigment or combination of pigments. Different brands might use different pigments for those. If you look around on the tube, you’ll find a list of the pigment codes. For red, it will be PR ### (Cadmium Red is PR 108). Knowing the pigment codes can help you compare between brands.
Hope this helps!
Tim
Thank you for sharing such a comprehensive response here Tim. Brilliant. 
Tim, thank you very much for your in-depth comprehensive, generous reply! I feel very fortunate that you took the time to explain all this! I do understand all the parameters you point out, but on a practical level I was wondering if anyone had the experience that some of these colors are, in theory, actually very close. I’ve studied the color numbers such as PR 108 for example, and unfortunately some manufacturers don’r list their proprietary concoctions. But at the end of the day the reds I listed here look very similar. I will do my own study and for my own amusement and learning exercise, share my results with the group. I think at the end of the day regardless of all the various factors that go into selecting the colors, I’m just wondering on a practical level which substitutions one might work in terms of these like families, given that I don’t really like waste. I guess I’ll find that out with my exercise of mixing them. That is of course the only way we can actually tell for sure. Thank you very very much for your lengthy answer. I really appreciate it! As a sidebar question, which cadmium would you believe vermilion was the closest to?
Hi Suzanne,
On a practical level, many (but not all!) pigments like the ones you mentioned are essentially interchangeable, depending on your needs and goals. For example, Cadmium Red, Pyrrol Red, and Chinese Vermillion would all sit next to each other on my palette if I were to squeeze out all of my pigments. All 3 look fairly close to each other, so it comes down to the properties I care about at the moment. Cad red will always do the job, but I find it a little overpowering - sort of a blunt instrument. I often find myself using the Pyrrol, since it has more transparency and makes more gracious mixtures.
The very best resource I’ve ever found for discussions of individual pigments is the astonishing Handprint site. Although the discussion is geared toward watercolor, you won’t find a more in-depth and cogent exploration of the pigments we all use: https://www.handprint.com/HP/WCL/waterfs.html
PS - my tubes of Michael Harding Cadmium Red and Holbein Chinese Vermillion are remarkable similar pigments.
+1 for Handprint. It’s an amazing resource.
I LOVE the handprint site! I’ve spent much time in there and find it full of information! The idea of transparency now arises, and with reds, or pure reds, if you will, are opaque. An artist friend of mine and I had a healthy argument around seven years ago about the fact that cadmium red (my interpretation) was opaque. she indicated to me that no colors were opaque, because essentially if you could thin them with oil or medium they all become transparent to some degree. If that were the case then why would we have the categories of opacity and transparency if they weren’t true or at least relatively true? Which leads me to the question of the actual difference between opacity and transparency. Is the actual difference tinting strength (without medium) hmmm… I better not stray too far from my original post lol.
Bruce MacEvoy’s Handprint has been an invaluable for me in the past as well. I quote or reference it often. We do have a link to it here on Smartermarx in the resources section.
Amazingly helpful and true response! Thanks for sharing your voice of experience!
Susan, I was delighted to discover in Paul Foxton’s course (that you have joined) that I could arrive at a particular color using quite a variety of pigments. Delighted, because I too was a close-out shopper when I first began to buy my oils and also bought many tubes recommended by any of over 30 instructors, plus artists I have followed on Facebook or the Net, resulting in a ridiculous quantity of tubes that I’d like to make use of, but probably mostly wouldn’t choose again since trying some premiums like Michael Harding, Daniel Smith, Natural Pigments, Williamsburg, and Vasari. But I still have some favorites from Gamblin and WN. If you scroll back to when Paul first started the Mastering color course you can see some enlarged charts, some more successful than others. Here’s a few examples:
