On 22 June 2026, PostNL released Janneke Brinkman – Zomerpalet (Summer Palette), a frame stamp sheet (kaderpostzegelvel) featuring 5 different stamps with botanical illustrations by renowned botanical artist Janneke Brinkman-Salentijn. The sheet celebrates the colours of summer through beautifully painted flowers and the insects that surround them.
Each stamp bears the denomination 1 for domestic mail up to 20 grams within the Netherlands. This is a highly limited issue of just 6,000 sheets, making it a coveted piece for collectors of Dutch frame stamps and botanical themes.
About Janneke Brinkman-Salentijn
Janneke Brinkman-Salentijn (Meppel, 1 March 1948) discovered her passion for detailed botanical drawing during her biology studies at the Vrije Universiteit in Amsterdam. She later took lessons from Leny Noyen and at the Leiden painting academy Ars Aemula Naturae. Her first exhibition was held in 1987 in The Hague, and she quickly became a renowned illustrator and aquarellist specialising in plants, flowers, and insects.
For many years, she created illustrations for the Dutch weekly magazine Margriet. Her work has appeared for over 30 years on diaries, calendars, greeting cards, puzzles, bed and kitchen textiles, and tableware. In 2017, she celebrated her 25-year jubilee as a botanical artist with an exhibition at Slot Zeist. To mark the occasion, PostNL issued a silver stamp titled 25 jaar Passie voor bloemen.
Earlier, in 2014, in collaboration with the Nationaal Ouderenfonds, she released the series of 8 stamp sheets Bloemen en vlinders (Flowers and Butterflies), organised by season. In 2025, the Herfstpalet (Autumn Palette) stamp sheet with 5 frame stamps was released — the predecessor to this Zomerpalet issue.
Design & Layout
The Zomerpalet sheet presents a beautiful bouquet on the centre stamp, surrounded by four individual flower stamps. From left to right, these feature an anemone, a rudbeckia (also known as black-eyed Susan or "gele zonnehoed"), and a pink and a purple-blue hibiscus. The individual blooms are carefully selected to harmonise in form and colour within the sheet's palette.
On the four stamps with individual flowers, butterflies, a bee, and a dragonfly are added, bringing the summer scene to life. The sheet margin continues the botanical theme with additional floral elements and insects.
Designer: Yvonne Warmerdam
The stamp sheet was designed by Yvonne Warmerdam, art director at Orange Licensing in Gouda. Warmerdam began by sketching the sheet margin, as it offered the most space to establish the overall atmosphere of the sheet.
"I chose the bouquet because it is specifically summery and very expressive," says Warmerdam. "The flowers painted by Janneke came from the organic farm Het Zoete Land in her hometown of Leiden and from her own garden. On the sheet margin, you see the largest part of the bouquet on the left. A portion of it — the part depicted above the first stamp — I repeated at the bottom right to balance the composition. At the top right of the sheet, you see a small piece from the lower left side of the bouquet. The white spaces that formed between these parts I filled with butterflies, bees, and a ladybug — that makes it playful and brings movement. These insects also come from Janneke's image bank. I only chose the illustrations for the stamps once we were satisfied with the sheet margin."
Technical Specifications
| Issue Date | 22 June 2026 |
| Issuing Authority | PostNL |
| Product Type | Kaderpostzegels (Frame stamps) |
| Stamps per Sheet | 5 (5 different designs) |
| Stamp Size | 30 × 40 mm |
| Sheet Size | 170 × 122 mm |
| Denomination | 1 (domestic mail up to 20 g) |
| Paper | Normal with phosphor coating |
| Gumming | Gummed (Gegomd) |
| Printing Colours | CMYK |
| Illustrations | Janneke Brinkman-Salentijn |
| Designer | Yvonne Warmerdam | Orange Licensing, Gouda |
| Printer | Koninklijke Joh. Enschedé B.V., Haarlem |
| Sheet Circulation | 6,000 sheets |
| Article Number | 860039 |
| Retail Price | €7.00 |
Why This Issue Matters
The Janneke Brinkman – Zomerpalet sheet is a must-have for collectors of Dutch frame stamps, botanical themes, and flora and fauna philately. With a limited circulation of just 6,000 sheets, it is one of the most exclusive PostNL issues of 2026.
This sheet forms a natural pair with the 2025 Herfstpalet issue, continuing Brinkman's seasonal series of botanical stamp sheets. The meticulous watercolour illustrations, combined with Yvonne Warmerdam's thoughtful sheet design — balancing the bouquet across the margin and stamps — make this a visually stunning addition to any collection. The inclusion of butterflies, bees, and dragonflies adds a delightful sense of summer life to the botanical artwork.