sources

Christine Scaman (12 Blueprints)

The bulk of my understanding of color seasons comes from Christine Scaman's self-published book, Return to Your Natural Colours (2nd Ed.). That’s now out of print, but she sells updated individual chapters at 12blueprints.teachable.com/courses/. 

I highly recommend her 12-season makeup products and fabric sample sets, available at 12blueprints.com (under the Shop tab).

Kathryn Kalisz

Christine Scaman's work is on Kathryn Kalisz's book Understanding Your Color—because Kalisz founded the Sci/Art color-analysis system in which Scaman was trained. Unfortunately, Kalisz died in 2010 under tragic circumstances. I haven't read her book because it's out of print and any available copies are wildly expensive.

See:

• "Kathryn Kalisz: A Story of Genius" by Terry Wildfong and Christine Scaman, Chrysalis Colour. Chrysaliscolour.com/about-us/kathryn-kalisz-a-story-of-genius/.
• "Kathryn Lee Kalisz," profile page, True Colour International. Truecolour.com.au/7912-2/.

Suzanne Caygill | Carole Jackson

I don't know who came up with the concept of seasonal color analysis, but Caygill seems like a strong contender. Her book, Color: The Essence of You came out the same year as Carole Jackson's bestselling Color Me Beautiful— 1980. 

Both books have similar ideas, but whereas Jackson originally only focused on the four main seasons (spring, summer, autumn, and winter), Caygill goes into different variations, listing at least 14 seasons. 

I haven't read the original Color Me Beautiful book, only some of the updated spinoff books, which now list all 12 seasons. (I'm not sure when that change happened.)

Caygill's book is available free online through the Cornell university library at hdl.handle.net/1813/55002.

Truth is Beauty

Rachel Arnt-Schemmel explains the 12-season system on her main color analysis page, and provides color examples and celebrity before-and-afters for all twelve seasons. I've learned a lot from her blog. 

However, she's sometimes wrong about celebrity seasons. For example, she lists Jennifer Garner as a true summer (should be soft summer) and Amanda Peet as a true winter (should be true summer).

Spicemarket Colour

I'm grateful to Helen Nuttall at Spicemarket Colour for all the celebrities she's color-typed. From her true winter celebrities page, I learned about Riz Ahmed and Constance Wu, as well as Zooey Deschanel in this particularly great navy-blue outfit.

As with Truth is Beauty, she's sometimes wrong about celebrity seasons (but she acknowledges up front that her celebrity typings are guesses). For example, she identified Joseph Gordon-Levitt and Maggie Q as dark autumn, but in my analysis, they're both dark winter.

Her blog posts are also great, such as this one on the face of true summer.

True Colour International

TCI is an organization offering color-analysis training and products, such as color fans. I enjoy the blog, such as this post in which the author color-analyzes their dog: "Subjective timbre: Getting it backwards."

However, the articles are aimed at expert color analysts and their clients, so they can be a little confusing for beginners.