There are a handful of pens that have achieved something close to legendary status among artists, illustrators, and crafters — and the Uni-ball Signo Broad UM-153 is firmly on that list. The white version in particular has developed a devoted following that borders on the evangelical, while the metallic colours have earned their place as the go-to choice for anyone who needs an opaque, reliable, genuinely beautiful metallic line. These are not novelty pens. They are proper tools that artists reach for repeatedly and replace when they run out.
The UM-153 has a 1.0mm conical metal tip that lays down a bold, wet, consistently smooth line with no skipping and no blobbing. The pigment-based gel ink is water-resistant once dry, lightfast, acid-free, and archival in quality — which matters more than it might seem for a pen at this price point. The ink dries quickly despite the generous flow, and once dry it holds up to watercolour washes, ink, and other wet media applied over it — making it particularly valuable for adding highlights and detail to mixed media work after the broader wet work is complete.
The four colours we stock each have their own distinct character:
White is the star of the range and one of the most-searched-for pens in the art world. The opacity is exceptional — thick, clean, and genuinely white rather than the milky semi-transparency that most white gel pens produce. It is the go-to choice for adding highlights to watercolour paintings, white lettering on dark paper and card, corrections on pen and ink drawings, and any application where a truly opaque white line is needed.
Gold is richly metallic and highly opaque, showing up brilliantly on both light and dark surfaces — paper, card, dark envelopes, black sketchbook pages, and dark-toned artworks alike.
Silver has the same opacity and metallic quality as Gold but with a cooler, brighter tone — equally at home on light and dark surfaces.
Bronze offers a warm, antique metallic tone that sits beautifully alongside Gold and works particularly well on natural and earthy coloured papers, kraft card, and dark backgrounds.
All four show up clearly on dark paper and card without any base layer or preparation needed. The pen has a clear acrylic barrel so ink levels are always visible, a rubberised grip for comfort in extended use, and a snap-fit cap. Made in Japan. Sold individually.
What makes the white version so popular with artists? The opacity of the UM-153 white is genuinely exceptional — considerably more opaque than most white gel pens, which tend to produce a semi-transparent milky line. The UM-153 lays down a thick, clean, fully opaque white that shows clearly on dark paper and card, and once dry can be worked over with watercolour and other wet media without lifting. For adding highlights to watercolour paintings it has become the default choice for a huge number of working artists.
Can these pens be used over watercolour? Yes — once the gel ink is fully dry it is water-resistant and will hold up to watercolour washes applied over the top. This makes the UM-153 particularly useful in mixed media work where wet media needs to be applied after the pen work is complete.
Do the metallic colours show up on dark paper? Yes — Gold, Silver, and Bronze are all highly opaque and show up clearly on dark paper, black card, kraft paper, and dark-toned artworks without any base layer needed.
What tip size does the UM-153 have? The tip is 1.0mm, producing a bold, broad line. For finer metallic work, the Uni-ball Signo UM-120 range offers a finer tip in a similar colour selection.
Is the ink archival quality? Yes — the pigment-based gel ink is acid-free, lightfast, and water-resistant once dry, making it suitable for finished artwork intended to last.
