One of the most exciting parts of knitting Fair-Isle or other Stranded Colourwork is picking the colours. Of course, that can also be the hardest part too. I love yarn lines that have a ridiculous number of colours available, but it can be awfully hard to narrow them down.
The sample for the pattern collection was done up with White, a range of four blues/greenish blues (Clarity, Icicle Heather, Marina, and Spruce), and the pinky-orange (Conch).
For my couch at home, I'm knitting up Firth Waves using White, Dove Heather as an additional neutral, Opal Heather as a grey-to-blue transitional colour, Fjord Heather (I think that's my current favourite from this selection), Marina to brighten things up, and Conch to make it really pop.
Now, to make a new colour scheme, I often play around with my chart, changing it with colours sampled from the website photos of yarn (not as perfect as having 100 different shades to play around with at home, but still pretty good). Of course, Knit Picks also has a kit builder, so if you head to the page for the Firth Cushion, you can play along just like I did this morning to come up with a few combos. For these examples I stuck with the main idea (as in the original) of using a neutral (or nearly neutral) along with one main colour family, and one contrasting colour:
1. White, Hollyberry, Calypso Heather, Oyster Heather, Rouge, and Blossom Heather (neutral, red-pinks, and a pop of teal)
2. Cloud, Brass Heather, Amethyst , Almond, Creme Brulee and Semolina (warm neutral, golds, and a pop of purple)
3. Seraphim, Sprinkle Heather, Golden Heather, Haze Heather, Amethyst Heather, Fairy Tale (purples with a pop of gold)
4. Oyster Heather, Chocolate, Tranquil, Almond, Persimmon Heather, Rooibos Heather (browns with Aqua)
I've kept it to fairly simple substitutions, though you could of course swap out the light background for a dark one with lighter motifs instead. Of course, it's also hard to say what they'll look like knit up until you knit them up, but here's how they could look in a modified version of the chart (using the sampling from photos as described above):
Using flat colours like I have here is nothing compared to actual yarn, particularly for the heathered colours, which are anything but flat. Still, these are all useful tools to help narrow things down, and can help you note a few issues with your selections, such as in number 3, where Seraphim is perhaps not high enough contrast; I would probably swap it out for White or Clout. I hope this will be of help to you in picking out your colours!