Is it possible to import a 16 bit-TIFF into Illustrator and then export it as a PDF?

[Guest]

I am creating a file for print. Since I want to have an image in there with very subtle gradients, I have this image as a 16 bit TIFF to escape the restricted number of colours of 8 bit files. Now Illustrator notifies me that it can only import it as an 8 bit file. For the view I'm fine with that since my monitor has only 8 bits anyway but since the print is pretty large, those lines will be visible. Is there a way to get around that and let the image in the output PDF be 16 bit?

[Mylenium]

Regular print output doesn't even cover the full gamut of an 8 bit RGB file. Only printers with custom "photo" inks can achieve a higher gamut, but that's not even close to full 16 bit, either. So for what it's worth, your approach simply doesn't make any sense. For predictable output you have to convert the file with full color management instated and possibly pulling all the stops to create manual ink separations with respective dithering so when printed together they will render an acceptable gradation. In fact even if a PDF could be 16 bit, it would be useless without color management since a low-gamut device has no way of knowing how to translate those high-fidelity colors. There really are no shortcuts here and from what you describe, even your screen output could be totally incorrect if not tailored to accomodate the 16bit to 8bit conversion by ways of using proper color management. Of course you can bypass all of that if you intend on handing this off to a trustworthy print company who use those aforementioned large format photo quality inkjet printers, but otherwise dealing with this the hard, academic, technical way is inevitable. I would suggest you do a bit of reading on this.

Mylenium

[Guest]

Thanks for your support. However, the problem is not color management but the gradient. As far as I can tell, the steps in the gradient will be visible especially since it resembles clouds on a dark sky (which is the reason why I can't use a vector gradient). I don't mind if the color is a bit off but what I worry about is the stepping in the gradients.

[Sjaani]

Which version of Illustrator are you using? I've just placed a 16 and 32 bit image into AI and saved as pdf without any warnings.

I'm also curious why you're using Illustrator for this. It sounds like InDesign might be a better option if you have access to it.

[Ton Frederiks]

You don't get any warnings, but if you look at the Document Info panel, they are all 24 bits per pixel.