Question :

I often have color pictures (like photos) that I would like to print in grayscale, but I don’t have a grayscale printer.

What is the simplest way to do so ?

Answer :

Having a color printer is great, and the easiest way to print grayscale pictures is to just select the grayscale-option before printing :

• open the picture (ussually a .jpg) in Preview.app
• in the top-bar, go to File and select Print from the pulldown list ; or press the [CMD]+[P] key-combo on your keyboard
• in the pulldown window that opens, click on Preview and select Graphics from the pulldown menu
• then, at Color Mode, select “Grayscale” (instead of “Color”)
• then click the Print-button and see what comes out of your printer
• Note that if you would make a PDF now, that it’s not going to be a grayscale picture…

Sometimes this will do just fine, but often that isn’t enough, and you will need to do a few extra steps to get an acceptable result out of your printer :

• open the picture (usually a .jpg) in Preview.app
• click on the “Show Markup toolbar”-button (the circle with the pen-point in it, just left of the Search-bar top-right)
• first, crop the image if needed :
  • then, click on the DashedSquare-icon (top-left) and select the “Rectangular Selection” option
  • on the picture, select the area you want to use (click the top-left of the envisioned area, than botom-right) and the selection area will be displayed
  • if you need to, adjust the selection area by dragging it’s edges
  • then, in the top-bar, go to Tools and select Crop from the pulldown list ; or type the [CMD]+[K] key-combo on your keyboard
  • now the picture will be croped to the smaller ‘selection only’ size
• then, in the top-bar, go to Tools and select Adjust Color from the pulldown list ; or type the [CMD]+[ALT]+[C] key combo on your keyboard
• in the AdjusColor-window that opens there is a ‘histogram’ (a picture with red/green/blue (a.k.a. RGB) graphs) with an AutoLevels-button, a list of 9 sliders and a ResetAll-button below it
• attached to the base of the histogram, there are 3 slider-pointers (a.k.a. histogram-sliders)
• set the middle histogram-slider lower (a little to the left)
• then set the right histogram-slider lower (a little to the left)
• then set the Exposure-slider higher (a little to the right)
• set the Contrast-slider higher (a little to the right)
• set the Sepia-slider in the middle
• set the Sharpness-slider higher (a little to the right)
• see if the (color) picture’s look is now clearer …if not go back and adjust the sliders until it is a brighter picture with more detail
• then, in the top-bar, go to File and select Print from the pulldown list ; or press the [CMD]+[P] key-combo on your keyboard
• in the pulldown window that opens, click on Preview and select Graphics from the pulldown menu
• then, at Color Mode, select “Grayscale” (instead of “Color”)
• then click the Print-button

that’s it !

Note : if you would make a PDF now, that it’s going to be a color-picture, not a grayscale picture… if you need a grayscale picture digitally, you will need to use Photoshop  or something similar…

Important extra note : once the picture is a PDF, you can no longer adjust the colors

enjoy 😉