An image processing apparatus comprising: a first selecting means for selecting an adjustment colour; a determining means for determining a colour arrangement of patches included in a chart to be printed by a printer, the colour arrangement of the patches being based on a colour value of the selected adjustment colour, and the chart including a patch corresponding to the adjustment colour and patches corresponding to respective stepwise neighbouring colours of the adjustment colour in Lab colour space, wherein the determining means determines the arrangement of the patches by, in a case where the L value of the Lab value of the adjustment colour is equal to or greater than a threshold (S607, YES), arranging the patches such that, among the patches corresponding to respective stepwise neighbouring colours of the adjustment colour in Lab colour space, patches that are arranged in the chart adjacent to the patch corresponding to the adjustment colour either have Lab values obtained by changing only the L value of the Lab value of the adjustment colour and/or the a value of the Lab value of the adjustment colour, or have Lab values obtained by only changing the L value of the Lab value of the adjustment colour and/or the b value of the Lab value of the adjustment colour; and by, in a case where the L value of the Lab value of the adjustment colour is less than the threshold (S607, NO), arranging the patches such that patches that are arranged in the chart adjacent to the patch corresponding to the adjustment colour have Lab values obtained by changing only the a value of the Lab value of the adjustment colour and /or the b value of the Lab value of the adjustment colour; a print controlling means (302, 303) for causing a printer to print the chart; a second selecting means for selecting a target colour from the colours corresponding to the respective patches on the chart by selecting a patch on the printed chart; and a generating means for generating a colour conversion table to be used for converting a colour to be printed by the printer, by using the adjustment colour selected by the first selecting means and the target colour selected by the second selecting means. a first selecting means for selecting an adjustment colour; a determining means for determining a colour arrangement of patches included in a chart to be printed by a printer, the colour arrangement of the patches being based on a colour value of the selected adjustment colour, and the chart including a patch corresponding to the adjustment colour and patches corresponding to respective stepwise neighbouring colours of the adjustment colour in Lab colour space, wherein the determining means determines the arrangement of the patches by, in a case where the L value of the Lab value of the adjustment colour is equal to or greater than a threshold (S607, YES), arranging the patches such that, among the patches corresponding to respective stepwise neighbouring colours of the adjustment colour in Lab colour space, patches that are arranged in the chart adjacent to the patch corresponding to the adjustment colour either have Lab values obtained by changing only the L value of the Lab value of the adjustment colour and/or the a value of the Lab value of the adjustment colour, or have Lab values obtained by only changing the L value of the Lab value of the adjustment colour and/or the b value of the Lab value of the adjustment colour; and by, in a case where the L value of the Lab value of the adjustment colour is less than the threshold (S607, NO), arranging the patches such that patches that are arranged in the chart adjacent to the patch corresponding to the adjustment colour have Lab values obtained by changing only the a value of the Lab value of the adjustment colour and /or the b value of the Lab value of the adjustment colour; a print controlling means (302, 303) for causing a printer to print the chart; a second selecting means for selecting a target colour from the colours corresponding to the respective patches on the chart by selecting a patch on the printed chart; and a generating means for generating a colour conversion table to be used for converting a colour to be printed by the printer, by using the adjustment colour selected by the first selecting means and the target colour selected by the second selecting means.