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.

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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.

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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 |
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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!
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