PRINTER PAPER/INK PROFILING by Barry Freeman ARPS

 

This method is based on producing a 0 to 100% (in 5% steps) RGB Greyscale image – set up with guidelines and each selected block filled with a calculated grey

  1. Open new document 10cm wide by 18cm high (suitable for A5 printing) at 300ppi
  2. Open rulers and set guidelines at 1,3,4,6,7,9cm verticals and 2,4,6,8,10,12,14,16cm horizontal.
  3. Set 2cmx2cm marquee over bottom left square and fill with 100% black
  4. Move marquee up one square and fill with 90% black – continue moving marquee and filling with black lowering the opacity by 5% each time, until 5% fill is reached. In the last square, which should be top right fill with 2% black to give an indication of just off-white.
  5. De-select the marquee. Switch off ruler and clear guidelines
  6. Number at the side of each square the % of white, i.e. 100% black fill = 0, 95% black fill = 0.05, 90% black fill = 0.1, etc. The base paper white is factor 1 or 256 brightness step. These represent the multiplying factors at the next stage.
  7. Printout at 720 or 1440 dpi, on chosen paper using generic profile but with no corrections
  8. Allow print to dry
  9. Scan (Epson 3200 Flat-bed) Set up for 300dpi – 48 bit colour [make sure that the colour configuration is set as ICM – the source: Epson Standard – the target: Adobe RGB – no colour correction]
  10. Scan printout with marquee of 185x110 (17 mB)
  11. In Photoshop choose a marquee to cover approximately ¾ of a block area and apply blur (average blur in CS)
  12. Move marquee to each block in turn and apply blur
  13. Set sampler to read 3x3 pixels
  14. Open a Curves adjustment layer
  15. Make initial eyedropper correction (black – white – 50% grey)
  16. Find where 50% grey is on curve and alter value of output to 128 (ie 0.5x256)
  17. Find and correct in 10% increments the curve output values – e.g. 90% should read 0.9x256=230 output value. Continue to give a resulting curve that corrects the brightness and contrast
  18. Close curves
  19. Open info pallet to check colour RGB balance of the grey squares and make a note the out of balance colours.
  20. Open curves to make correction of appropriate colour curve. (Placing curser over and clicking the square having the error will indicated the position on the colour curve)
  21. Gradually adjust colour of grey blocks to give near neutral grey throughout
  22. Save curve and name as a correction for the chosen paper/ink
  23. Close
  24. Open the original greyscale image and apply the new correction curve adjustment layer before printing
  25. Check for colour casts in each block
  26. Make minor adjustments if necessary to correction curve
  27. This adjustment curve layer is used for correction before printing colour or black/white prints on this specific paper/ink/printer combination