How should one prepare a file for print on Adobe programs (Most likely using Indesign for this project) when the paper is coloured?
I want to make a poster with text and other elements but no background, so that the printer doesn't try to print the background colour?
Is the default background on Adobe programs "transparent" or white? Meaning how does it behave when printed? So this is all when making a PDF file for print.
The default paper colour in InDesign is set to white and will export to PDF as transparent. You can colour and preview your print on coloured paper by adjusting the [Paper] swatch:
Double click the [Paper] swatch in your swatches panel and set the desired paper colour.
Note that changing the [Paper] swatch has no effect on the output file being created. So the exported PDF will have a transparent background.
In full-colour process (CMYK) printing, there is no white ink involved in the process. So, areas that are white will just be bare paper. This has nothing to do with Adobe software really, and ultimately depends on the printing process, since CMYK printing is not the only option.
It is certainly possible to have white ink printed, to cover over a coloured paper, but you'd have to ask your printer specifically for that.
There are several parts here. The other answers had addressed one of those two parts. There is no "white" on a file... Unless you prepare one.
So I want to address the other part... what do you want? What type of "printing" method do you need? what is the design look like? Are the inks transparent? Is the paper suitable to be printed on that method?
If the ink is transparent, are the colors complementary? Are the inks spot inks?
Do you know how the design will look once printed?
There is a chance you need to simulate the print with transparent inks using "multiply" on a simulation of the paper.
And you could need to prepare an additional layer of a white background, that needs to be printed as a spot ink if the paper is too dark.
You open InDesign, you type 'Lorem Ipsum' in black on a new document, you print on a pink sheet of paper, you get a black 'Lorem Ipsum' on a pink paper.
There will be no white involved. What you see as a white background in InDesign is actually transparent when printing.
If this is some random design paper, then you may be stuck with improvisation on tonal changes. But everything is not as bad as it seems. Check if paper is coated (glossy, shiny, typically used for magazines or packaging) or uncoated (doesn't shine, typical office, newspaper, book paper). Both of these types are most important, because default color profiles for them are already out of package made. Depends in what part of the world you are, there is coated/uncoated color profiles for your region.
But, if you have branded paper, you can also ask printer or check paper manufacturer homepage for corresponding color profile as it would be more precise.
As example, here are ARCTIC PAPER ICC PROFILES
