Method of forming positive color image

A method of forming a direct positive color image comprising

• image-wise exposing a photographic material having at least one emulsion layer which contains previously non-fogged internal latent image-type silver halide grains on a support and then
• color-developing the exposed photographic material during or after fogging, wherein the photographic material contains (A) a color sensitizing dye and (B) at least one tricyclic or tetracyclic heterocyclic compound or salt thereof which satisfies the following condition-1:
• Condition-1:
• 2 ml of an aqueous solution of 4.0.times.10.sup.-4 mol/liter of anhydro-5,5'-dichloro-9-ethyl-3,3 '-bis(3-sulfo-propyl) thiacarbocyanine-hydroxide pyridinium salt and 1 ml of an aqueous solution of 1.0.times.10.sup.-1 mol/liter of potassium chloride are blended, and 4 ml of an aqueous solution of 8.0.times.10.sup.-2 mol/liter of the compound (B) to be added to the photographic material is added to the resulting blended solution, which is then diluted with water to make 10 ml;
• with the molecular extinction coefficient of the resulting aqueous solution at 624 nm being 1.0.times.10.sup.5 or less,
• wherein said tricyclic or tetracyclic heterocyclic compound comprises a structural formula selected from the following formulae:
• ##STR13## wherein said tricyclic or tetracyclic heterocyclic compound may be substituted by a halogen atom, --OM (in which M represents a hydrogen atom or a monovalent metal such as Na, K or Li), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a cyano group, a nitro group, a sulfo group, a carboxyl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted aminosulfonyl group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryloxycarbonyl group, or a substituted or unsubstituted aminocarbonyl group.