Sailor Studio 640 Blue Ink Marker 26-5210-640

Sailor Studio 640 Blue Ink Marker 26-5210-640

• Steely Teal-Blue Core
  The bottled Sailor Ink Studio 640 is described by reviewers as a “beautiful dark teal” with a steely gray-blue influence. In swatch testing, Sailor’s 640 is portrayed as a “delicate deep grey blue that bleeds out greys and turquoise at the edges.”
  Thus, the marker version should embody a cooler, muted blue — more moody than bright, with a hint of green/teal undertone.

• High Shading, Medium Sheen & Long Dry Time
  In pen reviews, Ink Studio 640 shows high shading (distinct variation from light to dark in one stroke) and medium sheen, and is noted to have long dry times. This means in marker form, dense or layered strokes might show visible shine or gloss, and you’ll want to wait a bit before touching adjacent areas.

• Chromatographic Behavior / Edge Bleed
  Swatch testers observe that 640 “bleeds out greys and turquoise at the edges” when diluted or when water spreads the pigment. FOUNTAIN PEN INK ART+1 In a marker, finer edges or light strokes may show these tints — a soft halo effect in the periphery of strokes.

• Low Sheen in Some Conditions
  In field tests, some surfaces or paper types mute the sheen; but heavier saturation or pooling may still reveal subtle reflective luster. 

Given how Sailor has structured their Studio / Ink Studio line, plus how their markers are typically built, here are likely features and behaviors:

• Dual?Tip Design
  One end should house a brush tip (for expressive strokes, fills, gradient washes) and the opposite end a fine / hard tip (for outlines, accents, text).

• Water?Based Dye Ink
  The ink is expected to be a dye formulation (not pigmented), water soluble, adapted from the 640 fountain pen version for marker usage.

• Plastic Barrel & Functional Aesthetics
  The marker will likely use a plastic body (often light or neutral tone), with caps or accents matching the color (bluish or teal cues).

• Performance in Use

  • Smooth flow, especially in brush mode

  • Good responsiveness in fine tip mode

  • Potential for slight pooling or gloss in dense areas

  • Moderate to long dry time in deep strokes

  • Minimal feathering on quality paper; some edge bleeding or softening on porous paper

• Paper Matters: Use smooth, quality paper (marker paper, mixed-media, or fountain-pen–friendly) to preserve edge definition and let shading / chromatic effects show.

• Layering Strategy: Begin with light strokes, allow them to dry, then build up layers — avoid overworking until earlier layers settle.

• Dry Time Patience: Let generous strokes fully dry before overlapping to avoid smearing or color lifting.

• Edge Effects: Use lighter pressure or thinner lines if you want the soft turquoise / grey halo to appear.

• Cap & Store: Keep both ends capped when not in use. If tips seem dry after storage, scribble gently on scrap to revive flow.

• Blend & Contrast: 640 works beautifully next to cooler grays, darker blues, or greens to create interesting transitions or tonal contrast.