At the time of writing, it's gloomy and grey outside with intermittent downpours so when searching for inspiration for this week's newsletter we thought, what better way to perk up the day than to introduce you a spectrum of our most colourful collections?

The Medici Archive is a good place to start; a repository of classic twentieth century illustration by artists such as Margaret Tarrant, Molly Brett and Racey Helps. The latter is probably the most vibrantly-hued among this trio (although all produced gorgeous watercolours) but we would also prescribe some of the mid-century artworks from this collection by artists such as Kris, Esme Eve and Veronica Venus, rendered in an eye-popping rainbow palette. Here's an edit of some of our favourites but with the Medici archive comprising of over 15,000 original artworks, there are many more to choose from. In a similar genre, the Playhour archive is also bursting with vivid illustrations from the 1960s and 70s. Click here to get acquainted with Teddy Bear, the People You See series and much more.

The ILN archive seems to get a mention every Collections Crossover but deservedly so. It was a seedbed for some of the country's finest illustrators and cartoonists, with punchy cover designs, full-colour humour from the likes of H. M. Bateman and lots of other gorgeous creations by artists including William Heath Robinson, his brother Charles, Lawson Wood, Lewis Baumer and Cecil Aldin as well as experts of art deco elegance, Gordon Conway and Leon Benigni. Here's a taster.

Posters deserve a whole newsletter of their own, but we simply must mention them in a newsletter devoted to all things colourful. Onslow's, Kiki Werth and Twentieth Century Posters all provide us with some of the most dazzling examples of their kind, guaranteed to stand out on the hoardings. We've pulled together a few travel posters here as a sample.

Peter and Dawn Cope's collection specialises in illustrations for the nursery, particularly on postcards so is one to zone in on if your vibe is jolly and bright. This selection serves up delightful postcard designs as well as magazine illustrations, rag book pictures and other ephemera.

The CLM archive is a great resource for twentieth century art, especially the various images they have harvested from the prestigious magazine, Colour, which we had to mention, given the subject of this newsletter!

The multi-coloured natural world is well represented at the library with glorious examples of exotic birds, butterflies and hothouse blooms thanks to the Natural History Museum, Florilegius, Medici and Antiquarian Images.

Also in this vein, Robert Gillmor's linocuts of birds and wildlife are a feast of bold colour.

While we may have concentrated on art and illustration here, there's just time to highlight some notable colour photography. In John Hinde's postcards, seas and skies are of the deepest blue, grass is luscious green and any cars provide a convenient contrast in a uniform retro palette of red, pale blue and yellow. Remember we hold this archive on site and while we are gradually adding more postcards to our website, do let us know if you're looking for anything in particular and we can rummage in the filing cabinets. We also love finding early colour photographs published in the ILN magazines, such as John Everard's Bystander Beauties from 1933

We could talk about our dazzling film poster collection, nostalgic cartoon stills, acres of fine art, textile designs, Christmas cracker labels and Victorian paint charts but we've come to the end of the rainbow, or at least fear you may be on the verge of colour blindness.

We'll simply say we hope this newsletter has brightened up your day and whether you're looking for something in glorious technicolour, or even a subject that's spectacularly dull, we would love to help you out. Give us a call on 020 8318 0034, or email [email protected].