A three dimensional printing system for producing a three dimensional article of manufacturing comprising: a build platform; a powder dispensing apparatus; a light emitting device head having a columnar arrangement of light emitting devices that emit light having a defined spectral distribution; a drop ejecting head configured to separately eject a plurality of different inks having correspondingly different absorption coefficients for the defined spectral distribution; a movement mechanism; and a controller configured to: operate the powder dispensing apparatus to dispense a layer of fusible powder above the build platform; operate the movement mechanism to scan the drop ejecting head over the dispensed layer of powder; concurrent with scanning the drop ejecting head over the powder operate the drop ejecting head to define an array of inked pixels (40, 42) that have received varying amounts of the different inks whereby a resultant absorption coefficient of the inked pixels (40, 42) for the defined spectral distribution varies across the array of inked pixels; operate the movement mechanism to scan the light emitting device head over the inked pixels (40, 42); concurrent with scanning the light emitting device head over the inked pixels (40, 42) operate the light emitting devices to apply optical energy to the inked pixels (40, 42) whereby an optical energy per unit area is varied to compensate for the varying absorption coefficient of the inked pixels(40, 42). a build platform; a powder dispensing apparatus; a light emitting device head having a columnar arrangement of light emitting devices that emit light having a defined spectral distribution; a drop ejecting head configured to separately eject a plurality of different inks having correspondingly different absorption coefficients for the defined spectral distribution; a movement mechanism; and a controller configured to: operate the powder dispensing apparatus to dispense a layer of fusible powder above the build platform; operate the movement mechanism to scan the drop ejecting head over the dispensed layer of powder; concurrent with scanning the drop ejecting head over the powder operate the drop ejecting head to define an array of inked pixels (40, 42) that have received varying amounts of the different inks whereby a resultant absorption coefficient of the inked pixels (40, 42) for the defined spectral distribution varies across the array of inked pixels; operate the movement mechanism to scan the light emitting device head over the inked pixels (40, 42); concurrent with scanning the light emitting device head over the inked pixels (40, 42) operate the light emitting devices to apply optical energy to the inked pixels (40, 42) whereby an optical energy per unit area is varied to compensate for the varying absorption coefficient of the inked pixels(40, 42). operate the powder dispensing apparatus to dispense a layer of fusible powder above the build platform; operate the movement mechanism to scan the drop ejecting head over the dispensed layer of powder; concurrent with scanning the drop ejecting head over the powder operate the drop ejecting head to define an array of inked pixels (40, 42) that have received varying amounts of the different inks whereby a resultant absorption coefficient of the inked pixels (40, 42) for the defined spectral distribution varies across the array of inked pixels; operate the movement mechanism to scan the light emitting device head over the inked pixels (40, 42); concurrent with scanning the light emitting device head over the inked pixels (40, 42) operate the light emitting devices to apply optical energy to the inked pixels (40, 42) whereby an optical energy per unit area is varied to compensate for the varying absorption coefficient of the inked pixels(40, 42).