I'm really into the ColorLibrary colour separation profiles e.g. http://colorlibrary.ch/#blue-yellow

I wanted to use the blue and yellow one in a offset printed 2 colour book project, but as a student I don't have 40chf spare to purchase one. Does anyone has any ideas about how I would be able to achieve this effect myself? Tried googling but might be using the wrong terms. Any advice appreciated.


  • I must say that whoever made the page you linked to is not the brightest guy in the world. Man the page eats up your bandwidth like candy for almost no reason
    – joojaa
    Oct 12, 2017 at 18:09
  • 1
    Note thet 40 chf is not much money, if you spend severalhours waiting for an answer then 40 chf is a small sum
    – joojaa
    Oct 13, 2017 at 7:50
  • Take a look at this post: graphicdesign.stackexchange.com/questions/77703/…
    – Rafael
    Mar 13, 2018 at 17:30
  • Read the other responses before you comment! These processed images are based on the original hues, not just a greyscale image..
    – zackwww
    Jul 27, 2018 at 14:35

3 Answers 3


In photoshop: Image > mode > multichannel

Then, in your channels panel you can add, remove and adjust channels. As for the exact result, you have to experiment some based on your photograph and the desired result. Also, read through the documentation on the website you provided - even without buying the color library profiles, the principles are the same.

Edit: A small tutorial

Set your image mode to multichannel. Go to the channels panel, where you now have Cyan, Magenta and Yellow. Double click each one to change the color. Try picking spot colors from the color libraries instead of using the picker. Experiment with the number of channels and their solidity. I came a long way just by changing the magenta channel to grey and making cyan a little darker blue. And remember, what may work in one photo, might not work in every one. I haven't worked much in this mode, but my guess is that every photo needs a bit of work.


You can just convert your image to a duotone in Photoshop.

See Use duotones in Photoshop - Adobe Support...

  1. Convert your image to Grayscale (Image → Mode → Grayscale). You can use a Black & White adjustment layer first to control the conversion to grayscale if needs be.

  2. Convert your image to Duotone (Image → Mode → Duotone). Select the correct type for the number of colors you want to use, set those colors and adjust the curves for each color until your happy with the result. Duotones are single channel images so if you need to create the separations yourself...

  3. Convert your image to Multichannel mode (Image → Mode → Multichannel). This will separate your image in to the correct channels for each ink/plate/color.

A quick example...

enter image description here

Image 1: Original image

enter image description here

Image 2: Converting to Duotone

enter image description here

Image 3: Multichannel separations

Image source: https://www.pexels.com/photo/beautiful-blur-camera-capture-348528/

  • Thanks for the response but the ones in colorlibrary are different - they aren't just duotone based on a greyscale image, it's more complex and based on the original colours of the image - take a look back at the site - colorlibrary.ch/#blue-yellow
    – zackwww
    Oct 12, 2017 at 18:01
  • @zackwxyz dont accept posts that dont answer your question. Anyway your looking at differently spread tone.
    – joojaa
    Oct 12, 2017 at 18:10
  • @zackwxyz the output you get from ColorLibrary is the same as you get from what I explained; a multichannel file using colors other than CMYK (or whatever the input is). All the ColorLibrary profile does is do the channel adjustments etc for you.
    – Cai
    Oct 12, 2017 at 18:22
  • I don’t know how ColorLibrary converts the colors but this is the easiest way to do it without a profile
    – Cai
    Oct 12, 2017 at 18:22
  • sorry, new to the site, thought I was liking the response. yes you get a multichannel file using non CMYK colors but the output isn't the same visually. Thanks for your suggestion, but I was looking for how to do that specific method of separation. I think the other answer is closer to what I'm looking for but just trying to get my head around how to do it - not worked with channels before. Anyway, good to know that there are simple ways of achieving something similar, cheers.
    – zackwww
    Oct 12, 2017 at 18:34

One bad news. A lot of those images you are linking are not duotones... they are tritones. One Blue, yellow and black.

But let's see the color separations.

Using only one grayscale image is not good enough.

Take a look at this two posts:

Preparing design for duotone printing?

Printing photographs when job is a 2 spot color job

The basic idea is: take one "pure" channel, any of the RGB ones and use it as an ink. Use the opposite color.

On those two links I posted, I use one grayscale image as a base and one pure channel to do the "coloring".

But as you do not have a yellow channel I combined the Red and Green channel with multiply at the same time and used it as Blue. Then I used the blue as the yellow.

enter image description here

You also can tweak your CMYK color profile to reduce the amount of black used on the conversion.

Go to Edit>Color adjustments (May+Ctrl+K) And in the CMYK profile choose the enter image description herecustom profile. PLay with the settings there.

Then you can replace one ink with another color using multichannels.

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