Managing updates and revisions to both a full color version and a gray-scale version of the same image manually is not easy. Allow InDesign to offer (on import) either version. To do this, take advantage of a feature in Adobe Photoshop called Layer Comps.
The problem can be illustrated with a document that uses a full color version of a photo in one graphic frame and a black and white version of the photo in a second graphic frame. You could simply create a color version and save a copy as a black and white photo. However revisions and updates now require twice the work and twice the caution.
Instead, open the image in Photoshop. Save the image file as a Photoshop Document file. A PSD. By saving the tiff or jpeg or png as a PSD, InDesign will recognize the Layer Comp feature and allow you to make a choice as to which Layer Comp you’d like to apply when you import the file. Make sure to check the option to “Show Import Options”. This is a check-box that should be selected in the lower right area of the Place dialog box.
How do Layer Comps work? The quick answer is that Layer Comps are stored “states” of the settings you can apply to the Layers in a Photoshop Layer’s Panel. You can store the visibility, position and appearance properties of any layer in a Layer Comp.
In Photoshop the first task is to make sure the Adjustments panel is open (normally nested above the Layers panel). Click right next to the Scales (Color Balance) there is a small icon that looks like a box, split down the middle. One side is filled in. The other is not. This button creates a new Black and White Adjustment Layer.
Bring up the Layer Comps panel. You can open it from the Window menu in Photoshop. Click the Create New Layer Comp icon it is a button, in the lower left corner of the dialog box. Name the Layer Comp, perhaps calling it “Black and White version”. Make sure the Apply to Layers: Visibility check box is checked.
Return to the Layers panel. Uncheck the “indicates Layers visibility” switch. It looks like an open eye. This will hide the Black and White Adjustment Layer and remove the effect it has on the layer’s below. Thereby returning your image to full color. You’ll need to save this state of the Layers panel as a new Layer Comp. Click on the Create New Layer Comp button again. Give the Layer Comp a useful name, perhaps “Full Color Version”. Save the PSD file.
When you are ready to import the color version from within InDesign. Select the Place command, make sure the “Show Import Options” check box is checked. Import the PSD file. In the dialog box that opens, look in the lower right side, there will be a drop down menu with the Layer Comp versions available to choose. Choose the Layer Comp for the full color version.
Import the same file again, only this time choose the gray-scale version.
You can now update a single file at anytime back in Photoshop. The state of the layer comps will always be available on update and on import when you return to InDesign.