Light-polarizing film

A highly durable, dye light-polarizing film having neutral gray as well as a high polarizing coefficient, which comprises a polymer film made from polyvinyl alcohol or derivatives thereof having at least three dichroism dyes adsorbed and oriented therein, which is treated with an aqueous boric acid solution under the conditions wherein the concentration of boric acid is 5-10%, and the temperature is 50.degree.-80.degree. C.,

• said light-polarizing-film having, over a visible light region of 400-700 nm, a minumum polarizing coefficient of at least 70%, the difference between the minimum and a maximum polarizing coefficient is at most 20%, a minimum light transmittance of at least 20%, and the difference between the minimum and a maximum light transmittance is at most 20%;
• wherein the dichroism dyes are selected from the following respective classes of:
• (A) a yellow dichroism dye having a major absorption wavelength region in the range of 400-500 nm,
• (B) a black dichroism dye having a major absorption wavelength region in the range of 450-650 nm,
• (C) a blue dichroism dye having a major absorption wavelength region in the range of 570-700 nm,
• (D) an arange or red dichroism dye having a major absorption wavelength region in the range of 450-570 nm;
• and
• (E) a green dichroism dye having a major absorption wavelength region in the range of 600-700 nm or 400-450 nm.