Converting RGB Files for Black & White Printing

This topic has been covered by countless writers. However, we have so many customers that ask about how to make a better black & white inkjet prints, we decided to tackle the question here.

An important note before starting. There are different ways to convert a file from color RGB to black & white RGB and this is only one of them. If you know a better way the we 1) applaud you and 2) ask that you email us how you do it.

Back Story

Inkjet printers are designed to accept and process an RGB file into CMYK for printing. If you send a CMKY file to an inkjet printer, the results will be less than optimal. So, this means we need to find a way to convert your color RGB file into an RGB file that looks B&W.

How Its Done

Open a color RGB or sRGB file in Photoshop. You can make saturation, levels, and curves adjustments now and/or after the conversion. Practice and see what works for your needs, preferences, and files.

Example RGB file opened in Photoshop

Now go to the Image Menu and then the Mode Menu and select Lab Color.

Now go to your channels pallet - this is usually a tab located in the layers pallet. Go to Photoshop help if you cannot locate these pallets.

At left is the channels pallett Click on the Alpha channel and drag it to the trash can icon at the bottom of the menu. This will delete the alpha channel. You image changes to black and white at this point. Go to the Image menu and then the Mode menu. Select Grayscale. Go back to the Image menu and the Mode menu again and change your image to RGB mode.

The result is a black & white image RGB file. Here are the benefits of this arrangement: Ability to print with an ICC profile Ability to change the tone of the image with a Color Balance layer Much more control over tonal range, levels, and curves You give your inkjet printer a file it can work with Here's a secret - Inkjet printers are not very good at printing black and white consistently! This will not be a shocking revelation to many users. B&W inkjet prints tend to be toned green or red. If this happens now, you can make adjusting color changes with your new RGB file. Return to Red River home page

Update on 1/19/05 From helpful customer Dave W.

Dave writes:

I convert Color RGB images to B&W by Clicking on IMAGE then on ADJUST then on CHANNEL MIXER. When that opens click on MONOCHROME in lower left. This converts to B&W. Then Slide Red Channel to around +60 and Your Green Channel slider to about +40. Leave Blue channel at 0. You can use any combination of Red and Green, but your Red & Green should add up to 100 for best results.. You can make more adjustments with the Contant Slider at the bottom. I use to use the method you describe in your newsletter, but found this method worked just as good and was easier.

Thanks for the input!