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how to two color convertion?

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09876

Programmer
Nov 29, 2001
10
US
I have an artwork that has a blue logo and a Duotone image treated in Photoshop and then converted to CMYK. Now I need to convert this Illustrator (CMYK) artwork to two color job. How can I get this done in Illustrator CS?

Thanks,
 
. Before You Begin
Merge or Flatten Layers Into One

. Select a Portion of an Image with Channels

Although it literally takes one step to convert any color image to grayscale (Image, Greyscale), there's no guarantee that the result will be an attractive image. Professional photographers know that to get the best black-and-white print, you must use special black-and-white film; if you shoot an image in color and then print it in black and white, the image no longer contains the same points of drama and impact.

By separating a color image into channels, you have an opportunity to isolate each of the most dramatic elements of an image into a monochrome plane of its own. Sunlight bouncing off a subject, for example, shows greater reflectivity on some channels than on others. Low-level light bouncing off a colored object shows up as middle gray on one or two channels, black on the others. Those dark areas can provide both drama and balance in the final image. With the method you're about to see, you can pick and choose the lights and darks you want to create the perfect black-and-white image.

. Split the Color Image into Multiple Channels

Open your image and select Image, Split Channel, Split to HSL. Close the Hue and Saturation windows and save the Lightness window with the name Grayscale.

Change back to the color image, and select Image, Split Channel, Split to Close the Black channel and invert the Cyan, Magenta, and Yellow channels by selecting Adjust, Negative Image.

Analyze these three channels to determine which ones provide the most dramatic lights and darks; the Lightness channel (the renamed Grayscale image) will provide the middle grays. Close any windows you don't like, and the color image window as well, because you don't need it anymore.

. Add Light and Dark Layers As Desired

To borrow the dramatic lights from one of the channel images, activate that image and select Edit, Copy. Change to the Grayscale image. On the Layer palette, choose the topmost layer. Select Edit, Paste, Paste As New Layer to paste in the copied data. Change the Blend Mode of the new layer to Lighten for a nominal effect or to Screen for a bolder effect.

To borrow the darks from one of the channel images, follow the preceding instruction to copy and paste it as the top layer in the Grayscale image. Then change the Blend Mode to Darken for a nominal effect or to Multiply for a bolder effect.

Adjust the Opacity for each new layer to control how much of the light or dark effect it contributes to the final image. Repeat this step for as many channel layers as you care to add.

Tip - If the final product of your channel layering needs a contrast adjustment, add an adjustment layer to the top of the layers stack by selecting Layers, New Adjustment Layer, Levels.

. Merge and Clarify the Image

When you're satisfied with your layered result, select Layers, Merge, Merge All (Flatten). All the layers are merged into a single Background layer.

Finally, select Adjust, Brightness and Contrast, Clarify. Set the Strength of effect value to no higher than 3 and click OK. This setting brings back some of the intermediate gray values that the preceding adjustments and mergers tend to cancel out.

. View the Result

When you compare the image created using the Greyscale command with the one created through channel layering, you'll immediately notice a greater depth of shadows, midtones, and highlights. What layering in this manner gives you that ordinary grayscaling doesn't is the ability to retain the natural glowing edges and deep shadows that existed in the color version of this photograph.

Based on:
 
Hi bcastner,

First of all thanks for all the detail info. But Im wondering, are those instructions Adobe Illustrator CS?

Thanks,
 
That shows How to convert PART of an image to greyscale, and what I need is to create a two color PDF file from a Illustrator file so I can send to press.

Thanks,
 
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