One of the first articles written on this site discussed the (mis)use of the Registration colour. In short, Registration is a unique colour that – upon output – appears on every colour separation, primarily for the purpose of prepress marks such as registration crosshairs or crop marks.

If used in general artwork as a design feature, it can create problems by:
- Causing ink saturation values to be beyond recommended levels (i.e. a Full colour print containing registration colour in the artwork will have a 400% saturation value, but the paper stock may recommend no more than 320%);
- Cause artwork to print on digital machines at a higher click rate, as the software believes the artwork is full colour process, despite containing what may only appear to be black and white artwork.
Unfortunately, because it looks like a black swatch in the swatches palette, it can easily be confused for black and inadvertently selected instead of a black swatch.
Worse still, it may have been chosen on purpose because it gives a “blacker” black when output to a desktop printer. I have a separate article discussing the creation of more appropriate Rich black colours here.
Why not just delete the colour?
Unfortunately, it isn’t possible. The colour is one of four default colours (as indicated by the square brackets around the colour name), and as such cannot be deleted, nor added to a folder by itself.
However, the colours can be moved, so to make sure I don’t select Registration by mistake, I put it at the top of the swatch list.

Is there a script that can help?
Yes there is a script that will warn a user that they’ve selected the Registration colour – and it’s made by Adobe too, but it isn’t directly shipped with InDesign, but is available as part of their scripting tutorial guide.
First, make sure the InDesign application is not running.
Next, download the zip file linked above and then navigate to the following file and open it in a text editor such as notepad or textwrangler:

Once the file is open, change the following two lines:
var myDocument = app.documents.add(); myDocument.eventListeners.add("afterSelectionAttributeChanged", myCheckForRegistration);
To the following one line:
app.eventListeners.add("afterSelectionAttributeChanged", myCheckForRegistration);
Then save the file into the startup scripts folder, keeping the .jsx file extension.

Relaunch InDesign. From here, create a new document and draw a rectangle and attempt to fill it with Registration colour. Note the dialog that appears:

From here, click OK. Unfortunately, the script does not remove the Registration colour, but it should now be apparent that it needs to be fixed. I think if a user sees this enough times, they will get the idea not to select the Registration colour.
Just for fun, the dialog that appears can be adjusted to your liking. This is done by adjusting the line:
alert("The Registration swatch is applied to some of the\robjects in the selection. Did you really intend to apply this swatch?");
Anything within the quotation marks can be changed. The \r denotes a line break between the heading of the dialog box and the dialog text. For example:
alert("Good Grief!\rYou know better than that! Go back and select the Black swatch instead!");
Will yield the following dialog box:

There must be a better way!
That said, it is my own opinion that there should be a way to hide or lock the Registration colour via the Swatches “hamburger icon” so that it can’t be inadvertently selected without toggling an associated unhide/unlock feature. As usual, I’m not the only one who has thought so, and if you would like to vote on the topic, please do so here.
Similarly, it would be great if crop marks could be set to a user defined colour, rather than the default of Registration. This is moreso the case for digital printing where there are differences in costs between black and white click rates and full colour click rates. Fuji’s XMF imposition software already has a feature that allows users to change the colour of any prepress mark from Registration to:
- Darkest Colour (based on ink density); or
- A given colour that is entered by the user.