-ProfileMaker Profile for Printing in Grayscale
To print black-and-white (B&W) images on a color printer, you can create an RGB or CMYK ICC profile. The main concern is reducing color casts in images, as grays are highly sensitive to casts. Two techniques are described below. Use these if you want to (1) print B&W images that are already in grayscale mode, or (2) to print color images as B&W without prior conversion to grayscale. When printing the above to an Epson or other printer that does not have perfectly neutral K ink, a slight color cast may still be present.
REDUCING COLOR IN THE PROFILE
This technique is useful for printing images that are already in grayscale mode. To reduce the color cast in a CMYK printer profile, select separation settings that provide high GCR levels. GCR reduces CMY colors where they add up to gray, thus reducing the possibility of a color cast. High GCR can be created with the following separation settings:
- GCR "Max K"
- CMYK Max 200%
EDITING OUT THE COLOR
In addition, and to print color images as grayscale, you can edit the color out of the profile using ProfileEditor. This works for both RGB and CMYK printer profiles:
1) Before starting, open a test photo in Photoshop for use as a thumbnail. Resample to 72 dpi, convert to LAB mode, and save with a different name.
2) Launch ProfileEditor and open your printer profile.
3) Select the profile direction, LAB-to-CMYK.
4) Open your test photo from Step 1. Its mode must be in the starting point of the editing direction (LAB mode).
5) Select the Global Correction tool, and in the dialog box, reduce Saturation all the way (-100).
6) Save the profile under a different name.
SAVING A GRAYSCALE PROFILE
Another way to create a grayscale profile in ProfileEditor is to save a the profile as Grayscale (File > Save As > Gray ICC Profile). This can only be done with CMYK profiles, not RGB. If your grayscale images print too dark, you can lighten the profile using the Gradations tool.
GRAYSCALE CONVERSION IN PHOTOSHOP
Several methods can be used to convert a color image to grayscale in Photoshop:
- Mode Grayscale. Open RGB or CMYK image, and convert to Grayscale (Image > Mode > Grayscale).
- Mode LAB. Convert the image to LAB mode (L* = luminance, a* = red-green, and b* = blue-yellow). Delete the a* and b* (color) channels, leaving the L* (luminance), which is grayscale. Then convert the image to Grayscale mode.
- Calculations. Blend color from channels in the image (Image > Calculations). E.g., to create a grayscale from an RGB image using the red and green channels, in the Calculations dialog box, select the blend mode as Normal, first channel red, and second channel green. The opacity is the percent of the first channel used in the blend. After the calculation, convert the image to Grayscale mode.