I have been thinking about this for years and figured that today is the right time to actually ask someone about this: is it possible to apply grain to colors or gradients in Illustrator or InDesign without having to rasterize the affected object?
Why I am asking: we have a simple color gradient header in our documents - light blue to darker blue. Adding some subtle grain to this would make it look noticably better. However, if the grain would need to be rasterized, the size of the resulting document (PDF) would start to jump by the megabytes just because of this, which I really want to avoid.
- InDesign, simple A4 document, 25% of the page covered by the gradient (made in Illustrator) without noise: 7 kB PDF
- The same document, same gradient, with the noise effect applied: 2.5 MB PDF
The examples above are using the print quality present in Distiller. Using the preset for the smallest file size does reduce the size of the PDF, but the results are really ugly and definitely far from anything we could use in business.
This would naturally be solvable if there would be some property of the colors in the gradient that would define their noisiness - so that the noise would be computed instead of rasterized. I have seen something similar for example in Affinity Designer. Is something like this possible within the Adobe ecosystem?