Ink composition, ink set, and image forming method

An ink composition comprising a water-soluble alkali metal silicate, self-dispersing polymer particles, and a water-dispersible pigment,

• the self-dispersing polymer particles comprising a hydrophobic structural unit having an alicyclic group,
• the self-dispersing polymer particles having an I/O value of from 0.40 to 0.55, and
• the water-soluble alkali metal silicate being represented by the following Formula (S):
• x(M2O).y(SiO2) Formula (S)
• wherein, in Formula (S), M represents sodium or potassium;
• x represents 1 or 2;
• and y represents an integer from 1 to 4.

An ink composition comprising a water-soluble alkali metal silicate and a pigment coated with a water-insoluble resin,

• the water-insoluble resin comprising a structural unit having an acidic group and a structural unit derived from any of the following compounds:
• the water-soluble alkali metal silicate being represented by the following Formula (S):
• x(M2O).y(SiO2) Formula (S)
• wherein, in Formula (S), M represents sodium or potassium;
• x represents 1 or 2;
• and y represents an integer from 1 to 4.